[DISCUSSION] IgniteFuture class future in Ignite-3.0.

[Andrew Mashenkov]

Hi Igniters,

I'd like to start a discussion about replacing our custom IgniteFuture
class with CompletableFuture - existed JDK class
or rework it's implementation (like some other products done) to a
composition of CompletionStage and Future interfaces.
or maybe other option if you have any ideas. Do you?

1. The first approach pros and cons are
+ Well-known JDK class
+ Already implemented
- It is a class, not an interface.
- Expose some potentially harmful methods like "complete()".

On the other side, it has copy() method to create defensive copy and
minimalCompletionStage() to restrict harmful method usage.
Thus, this look like an applicable solution, but we should be careful
exposing internal future to the outside.

2. The second approach is to implement our own interface like the next one:

interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
}

Pros and cons are
+ Our interfaces/classes contracts will expose an interface rather than
concrete implementation.
+ All methods are safe.
- Some implementation is required.
- CompletableStage has a method toCompletableFuture() and can be converted
to CompletableFuture. This should be supported.

However, we still could wrap CompletableFuture and don't bother about
creating a defensive copy.


Other project experience:
* Spotify uses CompletableFuture directly [1].
* Redis goes the second approach [2]
* Vertx explicitly extends CompletableFuture [3]. However, they have custom
future classes and a number of helpers that could be replaced with
CompletableStage. Maybe it is just a legacy.'

Any thoughts?

[1]
https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
[2]
https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
[3]
https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
--
Best regards,
Andrey V. Mashenkov

[Atri Sharma-2]

I would suggest using CompletableFuture -- I don't see a need for a custom
interface that is unique to us.

It also allows a lower barrier for new contributors for understanding
existing code

On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <[hidden email]>
wrote:

> Hi Igniters,
>
> I'd like to start a discussion about replacing our custom IgniteFuture
> class with CompletableFuture - existed JDK class
> or rework it's implementation (like some other products done) to a
> composition of CompletionStage and Future interfaces.
> or maybe other option if you have any ideas. Do you?
>
> 1. The first approach pros and cons are
> + Well-known JDK class
> + Already implemented
> - It is a class, not an interface.
> - Expose some potentially harmful methods like "complete()".
>
> On the other side, it has copy() method to create defensive copy and
> minimalCompletionStage() to restrict harmful method usage.
> Thus, this look like an applicable solution, but we should be careful
> exposing internal future to the outside.
>
> 2. The second approach is to implement our own interface like the next one:
>
> interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
> }
>
> Pros and cons are
> + Our interfaces/classes contracts will expose an interface rather than
> concrete implementation.
> + All methods are safe.
> - Some implementation is required.
> - CompletableStage has a method toCompletableFuture() and can be converted
> to CompletableFuture. This should be supported.
>
> However, we still could wrap CompletableFuture and don't bother about
> creating a defensive copy.
>
>
> Other project experience:
> * Spotify uses CompletableFuture directly [1].
> * Redis goes the second approach [2]
> * Vertx explicitly extends CompletableFuture [3]. However, they have custom
> future classes and a number of helpers that could be replaced with
> CompletableStage. Maybe it is just a legacy.'
>
> Any thoughts?
>
> [1]
>
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> [2]
>
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> [3]
>
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> --
> Best regards,
> Andrey V. Mashenkov
>

[Alexei Scherbakov]

I think both options are fine, but personally lean toward CompletableFuture.

чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:

> I would suggest using CompletableFuture -- I don't see a need for a custom
> interface that is unique to us.
>
> It also allows a lower barrier for new contributors for understanding
> existing code
>
> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <[hidden email]>
> wrote:
>
> > Hi Igniters,
> >
> > I'd like to start a discussion about replacing our custom IgniteFuture
> > class with CompletableFuture - existed JDK class
> > or rework it's implementation (like some other products done) to a
> > composition of CompletionStage and Future interfaces.
> > or maybe other option if you have any ideas. Do you?
> >
> > 1. The first approach pros and cons are
> > + Well-known JDK class
> > + Already implemented
> > - It is a class, not an interface.
> > - Expose some potentially harmful methods like "complete()".
> >
> > On the other side, it has copy() method to create defensive copy and
> > minimalCompletionStage() to restrict harmful method usage.
> > Thus, this look like an applicable solution, but we should be careful
> > exposing internal future to the outside.
> >
> > 2. The second approach is to implement our own interface like the next
> one:
> >
> > interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
> > }
> >
> > Pros and cons are
> > + Our interfaces/classes contracts will expose an interface rather than
> > concrete implementation.
> > + All methods are safe.
> > - Some implementation is required.
> > - CompletableStage has a method toCompletableFuture() and can be
> converted
> > to CompletableFuture. This should be supported.
> >
> > However, we still could wrap CompletableFuture and don't bother about
> > creating a defensive copy.
> >
> >
> > Other project experience:
> > * Spotify uses CompletableFuture directly [1].
> > * Redis goes the second approach [2]
> > * Vertx explicitly extends CompletableFuture [3]. However, they have
> custom
> > future classes and a number of helpers that could be replaced with
> > CompletableStage. Maybe it is just a legacy.'
> >
> > Any thoughts?
> >
> > [1]
> >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > [2]
> >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > [3]
> >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > --
> > Best regards,
> > Andrey V. Mashenkov
> >
>

--

Best regards,
Alexei Scherbakov

[Valentin Kulichenko]

Andrey,

Can you compile a full list of these risky methods, and elaborate on what
the risks are?

Generally, CompletableFuture is a much better option, because it's
standard. But we need to make sure it actually fits our needs and doesn't
do more harm than good.

-Val

On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
[hidden email]> wrote:

> I think both options are fine, but personally lean toward
> CompletableFuture.
>
> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
>
> > I would suggest using CompletableFuture -- I don't see a need for a
> custom
> > interface that is unique to us.
> >
> > It also allows a lower barrier for new contributors for understanding
> > existing code
> >
> > On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <[hidden email]
> >
> > wrote:
> >
> > > Hi Igniters,
> > >
> > > I'd like to start a discussion about replacing our custom IgniteFuture
> > > class with CompletableFuture - existed JDK class
> > > or rework it's implementation (like some other products done) to a
> > > composition of CompletionStage and Future interfaces.
> > > or maybe other option if you have any ideas. Do you?
> > >
> > > 1. The first approach pros and cons are
> > > + Well-known JDK class
> > > + Already implemented
> > > - It is a class, not an interface.
> > > - Expose some potentially harmful methods like "complete()".
> > >
> > > On the other side, it has copy() method to create defensive copy and
> > > minimalCompletionStage() to restrict harmful method usage.
> > > Thus, this look like an applicable solution, but we should be careful
> > > exposing internal future to the outside.
> > >
> > > 2. The second approach is to implement our own interface like the next
> > one:
> > >
> > > interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
> > > }
> > >
> > > Pros and cons are
> > > + Our interfaces/classes contracts will expose an interface rather than
> > > concrete implementation.
> > > + All methods are safe.
> > > - Some implementation is required.
> > > - CompletableStage has a method toCompletableFuture() and can be
> > converted
> > > to CompletableFuture. This should be supported.
> > >
> > > However, we still could wrap CompletableFuture and don't bother about
> > > creating a defensive copy.
> > >
> > >
> > > Other project experience:
> > > * Spotify uses CompletableFuture directly [1].
> > > * Redis goes the second approach [2]
> > > * Vertx explicitly extends CompletableFuture [3]. However, they have
> > custom
> > > future classes and a number of helpers that could be replaced with
> > > CompletableStage. Maybe it is just a legacy.'
> > >
> > > Any thoughts?
> > >
> > > [1]
> > >
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > [2]
> > >
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > [3]
> > >
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > --
> > > Best regards,
> > > Andrey V. Mashenkov
> > >
> >
>
>
> --
>
> Best regards,
> Alexei Scherbakov
>

[Alexey Kukushkin]

I do not like Java's CompletableFuture and prefer our own Future (revised
IgniteFuture).

My understanding of the Future (or Promise) pattern in general is having
two separate APIs:

   1. Server-side: create, set result, raise error, cancel from server.
   2. Client-side: get result, handle error, cancel from client

Java's CompletableFuture looks like both the client-side and
server-side API. The "Completeable" prefix in the name is already confusing
for a client since it cannot "complete" an operation, only a server can.

I would create our own IgniteFuture adding client-side functionality we
currently miss (like client-side cancellation).


пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
[hidden email]>:

> Andrey,
>
> Can you compile a full list of these risky methods, and elaborate on what
> the risks are?
>
> Generally, CompletableFuture is a much better option, because it's
> standard. But we need to make sure it actually fits our needs and doesn't
> do more harm than good.
>
> -Val
>
> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> [hidden email]> wrote:
>
> > I think both options are fine, but personally lean toward
> > CompletableFuture.
> >
> > чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
> >
> > > I would suggest using CompletableFuture -- I don't see a need for a
> > custom
> > > interface that is unique to us.
> > >
> > > It also allows a lower barrier for new contributors for understanding
> > > existing code
> > >
> > > On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> [hidden email]
> > >
> > > wrote:
> > >
> > > > Hi Igniters,
> > > >
> > > > I'd like to start a discussion about replacing our custom
> IgniteFuture
> > > > class with CompletableFuture - existed JDK class
> > > > or rework it's implementation (like some other products done) to a
> > > > composition of CompletionStage and Future interfaces.
> > > > or maybe other option if you have any ideas. Do you?
> > > >
> > > > 1. The first approach pros and cons are
> > > > + Well-known JDK class
> > > > + Already implemented
> > > > - It is a class, not an interface.
> > > > - Expose some potentially harmful methods like "complete()".
> > > >
> > > > On the other side, it has copy() method to create defensive copy and
> > > > minimalCompletionStage() to restrict harmful method usage.
> > > > Thus, this look like an applicable solution, but we should be careful
> > > > exposing internal future to the outside.
> > > >
> > > > 2. The second approach is to implement our own interface like the
> next
> > > one:
> > > >
> > > > interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
> > > > }
> > > >
> > > > Pros and cons are
> > > > + Our interfaces/classes contracts will expose an interface rather
> than
> > > > concrete implementation.
> > > > + All methods are safe.
> > > > - Some implementation is required.
> > > > - CompletableStage has a method toCompletableFuture() and can be
> > > converted
> > > > to CompletableFuture. This should be supported.
> > > >
> > > > However, we still could wrap CompletableFuture and don't bother about
> > > > creating a defensive copy.
> > > >
> > > >
> > > > Other project experience:
> > > > * Spotify uses CompletableFuture directly [1].
> > > > * Redis goes the second approach [2]
> > > > * Vertx explicitly extends CompletableFuture [3]. However, they have
> > > custom
> > > > future classes and a number of helpers that could be replaced with
> > > > CompletableStage. Maybe it is just a legacy.'
> > > >
> > > > Any thoughts?
> > > >
> > > > [1]
> > > >
> > > >
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > > [2]
> > > >
> > > >
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > > [3]
> > > >
> > > >
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > > --
> > > > Best regards,
> > > > Andrey V. Mashenkov
> > > >
> > >
> >
> >
> > --
> >
> > Best regards,
> > Alexei Scherbakov
> >
>

--
Best regards,
Alexey

[Pavel Tupitsyn]

On the one hand, I agree with Alexey.
CompletableFuture has complete* methods which should not be available to
the user code.
This can be solved with a simple interface like we do in Thin Client:
IgniteClientFuture<T> extends Future<T>, CompletionStage<T>


On the other hand:
- CompletionStage has toCompletableFuture anyway (rather weird)
- Other libraries use CompletableFuture and it seems to be fine
- Using CompletableFuture is the simplest approach


So I lean towards CompletableFuture too.

On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <[hidden email]>
wrote:

> I do not like Java's CompletableFuture and prefer our own Future (revised
> IgniteFuture).
>
> My understanding of the Future (or Promise) pattern in general is having
> two separate APIs:
>
>    1. Server-side: create, set result, raise error, cancel from server.
>    2. Client-side: get result, handle error, cancel from client
>
> Java's CompletableFuture looks like both the client-side and
> server-side API. The "Completeable" prefix in the name is already confusing
> for a client since it cannot "complete" an operation, only a server can.
>
> I would create our own IgniteFuture adding client-side functionality we
> currently miss (like client-side cancellation).
>
>
> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> [hidden email]>:
>
> > Andrey,
> >
> > Can you compile a full list of these risky methods, and elaborate on what
> > the risks are?
> >
> > Generally, CompletableFuture is a much better option, because it's
> > standard. But we need to make sure it actually fits our needs and doesn't
> > do more harm than good.
> >
> > -Val
> >
> > On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> > [hidden email]> wrote:
> >
> > > I think both options are fine, but personally lean toward
> > > CompletableFuture.
> > >
> > > чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
> > >
> > > > I would suggest using CompletableFuture -- I don't see a need for a
> > > custom
> > > > interface that is unique to us.
> > > >
> > > > It also allows a lower barrier for new contributors for understanding
> > > > existing code
> > > >
> > > > On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > [hidden email]
> > > >
> > > > wrote:
> > > >
> > > > > Hi Igniters,
> > > > >
> > > > > I'd like to start a discussion about replacing our custom
> > IgniteFuture
> > > > > class with CompletableFuture - existed JDK class
> > > > > or rework it's implementation (like some other products done) to a
> > > > > composition of CompletionStage and Future interfaces.
> > > > > or maybe other option if you have any ideas. Do you?
> > > > >
> > > > > 1. The first approach pros and cons are
> > > > > + Well-known JDK class
> > > > > + Already implemented
> > > > > - It is a class, not an interface.
> > > > > - Expose some potentially harmful methods like "complete()".
> > > > >
> > > > > On the other side, it has copy() method to create defensive copy
> and
> > > > > minimalCompletionStage() to restrict harmful method usage.
> > > > > Thus, this look like an applicable solution, but we should be
> careful
> > > > > exposing internal future to the outside.
> > > > >
> > > > > 2. The second approach is to implement our own interface like the
> > next
> > > > one:
> > > > >
> > > > > interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
> > > > > }
> > > > >
> > > > > Pros and cons are
> > > > > + Our interfaces/classes contracts will expose an interface rather
> > than
> > > > > concrete implementation.
> > > > > + All methods are safe.
> > > > > - Some implementation is required.
> > > > > - CompletableStage has a method toCompletableFuture() and can be
> > > > converted
> > > > > to CompletableFuture. This should be supported.
> > > > >
> > > > > However, we still could wrap CompletableFuture and don't bother
> about
> > > > > creating a defensive copy.
> > > > >
> > > > >
> > > > > Other project experience:
> > > > > * Spotify uses CompletableFuture directly [1].
> > > > > * Redis goes the second approach [2]
> > > > > * Vertx explicitly extends CompletableFuture [3]. However, they
> have
> > > > custom
> > > > > future classes and a number of helpers that could be replaced with
> > > > > CompletableStage. Maybe it is just a legacy.'
> > > > >
> > > > > Any thoughts?
> > > > >
> > > > > [1]
> > > > >
> > > > >
> > > >
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > > > [2]
> > > > >
> > > > >
> > > >
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > > > [3]
> > > > >
> > > > >
> > > >
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > > > --
> > > > > Best regards,
> > > > > Andrey V. Mashenkov
> > > > >
> > > >
> > >
> > >
> > > --
> > >
> > > Best regards,
> > > Alexei Scherbakov
> > >
> >
>
>
> --
> Best regards,
> Alexey
>

[Konstantin Orlov]

CompletableFuture seems a better option to me.

--
Regards,
Konstantin Orlov

> On 26 Mar 2021, at 11:07, Pavel Tupitsyn <[hidden email]> wrote:
>
> On the one hand, I agree with Alexey.
> CompletableFuture has complete* methods which should not be available to
> the user code.
> This can be solved with a simple interface like we do in Thin Client:
> IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
>
>
> On the other hand:
> - CompletionStage has toCompletableFuture anyway (rather weird)
> - Other libraries use CompletableFuture and it seems to be fine
> - Using CompletableFuture is the simplest approach
>
>
> So I lean towards CompletableFuture too.
>
> On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <[hidden email]>
> wrote:
>
>> I do not like Java's CompletableFuture and prefer our own Future (revised
>> IgniteFuture).
>>
>> My understanding of the Future (or Promise) pattern in general is having
>> two separate APIs:
>>
>>   1. Server-side: create, set result, raise error, cancel from server.
>>   2. Client-side: get result, handle error, cancel from client
>>
>> Java's CompletableFuture looks like both the client-side and
>> server-side API. The "Completeable" prefix in the name is already confusing
>> for a client since it cannot "complete" an operation, only a server can.
>>
>> I would create our own IgniteFuture adding client-side functionality we
>> currently miss (like client-side cancellation).
>>
>>
>> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
>> [hidden email]>:
>>
>>> Andrey,
>>>
>>> Can you compile a full list of these risky methods, and elaborate on what
>>> the risks are?
>>>
>>> Generally, CompletableFuture is a much better option, because it's
>>> standard. But we need to make sure it actually fits our needs and doesn't
>>> do more harm than good.
>>>
>>> -Val
>>>
>>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
>>> [hidden email]> wrote:
>>>
>>>> I think both options are fine, but personally lean toward
>>>> CompletableFuture.
>>>>
>>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
>>>>
>>>>> I would suggest using CompletableFuture -- I don't see a need for a
>>>> custom
>>>>> interface that is unique to us.
>>>>>
>>>>> It also allows a lower barrier for new contributors for understanding
>>>>> existing code
>>>>>
>>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
>>> [hidden email]
>>>>>
>>>>> wrote:
>>>>>
>>>>>> Hi Igniters,
>>>>>>
>>>>>> I'd like to start a discussion about replacing our custom
>>> IgniteFuture
>>>>>> class with CompletableFuture - existed JDK class
>>>>>> or rework it's implementation (like some other products done) to a
>>>>>> composition of CompletionStage and Future interfaces.
>>>>>> or maybe other option if you have any ideas. Do you?
>>>>>>
>>>>>> 1. The first approach pros and cons are
>>>>>> + Well-known JDK class
>>>>>> + Already implemented
>>>>>> - It is a class, not an interface.
>>>>>> - Expose some potentially harmful methods like "complete()".
>>>>>>
>>>>>> On the other side, it has copy() method to create defensive copy
>> and
>>>>>> minimalCompletionStage() to restrict harmful method usage.
>>>>>> Thus, this look like an applicable solution, but we should be
>> careful
>>>>>> exposing internal future to the outside.
>>>>>>
>>>>>> 2. The second approach is to implement our own interface like the
>>> next
>>>>> one:
>>>>>>
>>>>>> interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
>>>>>> }
>>>>>>
>>>>>> Pros and cons are
>>>>>> + Our interfaces/classes contracts will expose an interface rather
>>> than
>>>>>> concrete implementation.
>>>>>> + All methods are safe.
>>>>>> - Some implementation is required.
>>>>>> - CompletableStage has a method toCompletableFuture() and can be
>>>>> converted
>>>>>> to CompletableFuture. This should be supported.
>>>>>>
>>>>>> However, we still could wrap CompletableFuture and don't bother
>> about
>>>>>> creating a defensive copy.
>>>>>>
>>>>>>
>>>>>> Other project experience:
>>>>>> * Spotify uses CompletableFuture directly [1].
>>>>>> * Redis goes the second approach [2]
>>>>>> * Vertx explicitly extends CompletableFuture [3]. However, they
>> have
>>>>> custom
>>>>>> future classes and a number of helpers that could be replaced with
>>>>>> CompletableStage. Maybe it is just a legacy.'
>>>>>>
>>>>>> Any thoughts?
>>>>>>
>>>>>> [1]
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
>>>>>> [2]
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
>>>>>> [3]
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
>>>>>> --
>>>>>> Best regards,
>>>>>> Andrey V. Mashenkov
>>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> Best regards,
>>>> Alexei Scherbakov
>>>>
>>>
>>
>>
>> --
>> Best regards,
>> Alexey
>>

[Andrew Mashenkov]

Val,

The methods below shouldn't be accessible for user:
complete()
completeExceptionaly()

Returning CompletableFuture we must always make a copy to prevent the
original future from being completed by mistake.
I think it will NOT be enough to do that returing the future to the
end-user, but from every critical module to the outside of the module,
e.g. to plugins. The impact of disclosing ExchangeFuture,
PartitionReleaseFuture to plugins may be serious.

IgniteFuture<T> extends Future<T>, CompletionStage<T> which implementation
will just wrap CompletableFuture these issues will be resolved in natural
way.
In addition we can force toCompletableFuture() method to return a defensive
copy(), that resolves the last concern.


On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov <[hidden email]>
wrote:

> CompletableFuture seems a better option to me.
>
> --
> Regards,
> Konstantin Orlov
>
>
>
>
> > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <[hidden email]> wrote:
> >
> > On the one hand, I agree with Alexey.
> > CompletableFuture has complete* methods which should not be available to
> > the user code.
> > This can be solved with a simple interface like we do in Thin Client:
> > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
> >
> >
> > On the other hand:
> > - CompletionStage has toCompletableFuture anyway (rather weird)
> > - Other libraries use CompletableFuture and it seems to be fine
> > - Using CompletableFuture is the simplest approach
> >
> >
> > So I lean towards CompletableFuture too.
> >
> > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> [hidden email]>
> > wrote:
> >
> >> I do not like Java's CompletableFuture and prefer our own Future
> (revised
> >> IgniteFuture).
> >>
> >> My understanding of the Future (or Promise) pattern in general is having
> >> two separate APIs:
> >>
> >>   1. Server-side: create, set result, raise error, cancel from server.
> >>   2. Client-side: get result, handle error, cancel from client
> >>
> >> Java's CompletableFuture looks like both the client-side and
> >> server-side API. The "Completeable" prefix in the name is already
> confusing
> >> for a client since it cannot "complete" an operation, only a server can.
> >>
> >> I would create our own IgniteFuture adding client-side functionality we
> >> currently miss (like client-side cancellation).
> >>
> >>
> >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> >> [hidden email]>:
> >>
> >>> Andrey,
> >>>
> >>> Can you compile a full list of these risky methods, and elaborate on
> what
> >>> the risks are?
> >>>
> >>> Generally, CompletableFuture is a much better option, because it's
> >>> standard. But we need to make sure it actually fits our needs and
> doesn't
> >>> do more harm than good.
> >>>
> >>> -Val
> >>>
> >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> >>> [hidden email]> wrote:
> >>>
> >>>> I think both options are fine, but personally lean toward
> >>>> CompletableFuture.
> >>>>
> >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
> >>>>
> >>>>> I would suggest using CompletableFuture -- I don't see a need for a
> >>>> custom
> >>>>> interface that is unique to us.
> >>>>>
> >>>>> It also allows a lower barrier for new contributors for understanding
> >>>>> existing code
> >>>>>
> >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> >>> [hidden email]
> >>>>>
> >>>>> wrote:
> >>>>>
> >>>>>> Hi Igniters,
> >>>>>>
> >>>>>> I'd like to start a discussion about replacing our custom
> >>> IgniteFuture
> >>>>>> class with CompletableFuture - existed JDK class
> >>>>>> or rework it's implementation (like some other products done) to a
> >>>>>> composition of CompletionStage and Future interfaces.
> >>>>>> or maybe other option if you have any ideas. Do you?
> >>>>>>
> >>>>>> 1. The first approach pros and cons are
> >>>>>> + Well-known JDK class
> >>>>>> + Already implemented
> >>>>>> - It is a class, not an interface.
> >>>>>> - Expose some potentially harmful methods like "complete()".
> >>>>>>
> >>>>>> On the other side, it has copy() method to create defensive copy
> >> and
> >>>>>> minimalCompletionStage() to restrict harmful method usage.
> >>>>>> Thus, this look like an applicable solution, but we should be
> >> careful
> >>>>>> exposing internal future to the outside.
> >>>>>>
> >>>>>> 2. The second approach is to implement our own interface like the
> >>> next
> >>>>> one:
> >>>>>>
> >>>>>> interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
> >>>>>> }
> >>>>>>
> >>>>>> Pros and cons are
> >>>>>> + Our interfaces/classes contracts will expose an interface rather
> >>> than
> >>>>>> concrete implementation.
> >>>>>> + All methods are safe.
> >>>>>> - Some implementation is required.
> >>>>>> - CompletableStage has a method toCompletableFuture() and can be
> >>>>> converted
> >>>>>> to CompletableFuture. This should be supported.
> >>>>>>
> >>>>>> However, we still could wrap CompletableFuture and don't bother
> >> about
> >>>>>> creating a defensive copy.
> >>>>>>
> >>>>>>
> >>>>>> Other project experience:
> >>>>>> * Spotify uses CompletableFuture directly [1].
> >>>>>> * Redis goes the second approach [2]
> >>>>>> * Vertx explicitly extends CompletableFuture [3]. However, they
> >> have
> >>>>> custom
> >>>>>> future classes and a number of helpers that could be replaced with
> >>>>>> CompletableStage. Maybe it is just a legacy.'
> >>>>>>
> >>>>>> Any thoughts?
> >>>>>>
> >>>>>> [1]
> >>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> >>>>>> [2]
> >>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> >>>>>> [3]
> >>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> >>>>>> --
> >>>>>> Best regards,
> >>>>>> Andrey V. Mashenkov
> >>>>>>
> >>>>>
> >>>>
> >>>>
> >>>> --
> >>>>
> >>>> Best regards,
> >>>> Alexei Scherbakov
> >>>>
> >>>
> >>
> >>
> >> --
> >> Best regards,
> >> Alexey
> >>
>
>

--
Best regards,
Andrey V. Mashenkov

[Valentin Kulichenko]

Andrey,

I see. So in a nutshell, you're saying that we want to return a future that
the user's code is not allowed to complete. In this case, I think it's
clear that CompletableFuture is not what we need. We actually need a
NonCompletableFuture :)

My vote is for the custom interface.

-Val

On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov <[hidden email]>
wrote:

> Val,
>
> The methods below shouldn't be accessible for user:
> complete()
> completeExceptionaly()
>
> Returning CompletableFuture we must always make a copy to prevent the
> original future from being completed by mistake.
> I think it will NOT be enough to do that returing the future to the
> end-user, but from every critical module to the outside of the module,
> e.g. to plugins. The impact of disclosing ExchangeFuture,
> PartitionReleaseFuture to plugins may be serious.
>
> IgniteFuture<T> extends Future<T>, CompletionStage<T> which implementation
> will just wrap CompletableFuture these issues will be resolved in natural
> way.
> In addition we can force toCompletableFuture() method to return a defensive
> copy(), that resolves the last concern.
>
>
> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov <[hidden email]>
> wrote:
>
> > CompletableFuture seems a better option to me.
> >
> > --
> > Regards,
> > Konstantin Orlov
> >
> >
> >
> >
> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <[hidden email]> wrote:
> > >
> > > On the one hand, I agree with Alexey.
> > > CompletableFuture has complete* methods which should not be available
> to
> > > the user code.
> > > This can be solved with a simple interface like we do in Thin Client:
> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
> > >
> > >
> > > On the other hand:
> > > - CompletionStage has toCompletableFuture anyway (rather weird)
> > > - Other libraries use CompletableFuture and it seems to be fine
> > > - Using CompletableFuture is the simplest approach
> > >
> > >
> > > So I lean towards CompletableFuture too.
> > >
> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> > [hidden email]>
> > > wrote:
> > >
> > >> I do not like Java's CompletableFuture and prefer our own Future
> > (revised
> > >> IgniteFuture).
> > >>
> > >> My understanding of the Future (or Promise) pattern in general is
> having
> > >> two separate APIs:
> > >>
> > >>   1. Server-side: create, set result, raise error, cancel from server.
> > >>   2. Client-side: get result, handle error, cancel from client
> > >>
> > >> Java's CompletableFuture looks like both the client-side and
> > >> server-side API. The "Completeable" prefix in the name is already
> > confusing
> > >> for a client since it cannot "complete" an operation, only a server
> can.
> > >>
> > >> I would create our own IgniteFuture adding client-side functionality
> we
> > >> currently miss (like client-side cancellation).
> > >>
> > >>
> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> > >> [hidden email]>:
> > >>
> > >>> Andrey,
> > >>>
> > >>> Can you compile a full list of these risky methods, and elaborate on
> > what
> > >>> the risks are?
> > >>>
> > >>> Generally, CompletableFuture is a much better option, because it's
> > >>> standard. But we need to make sure it actually fits our needs and
> > doesn't
> > >>> do more harm than good.
> > >>>
> > >>> -Val
> > >>>
> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> > >>> [hidden email]> wrote:
> > >>>
> > >>>> I think both options are fine, but personally lean toward
> > >>>> CompletableFuture.
> > >>>>
> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
> > >>>>
> > >>>>> I would suggest using CompletableFuture -- I don't see a need for a
> > >>>> custom
> > >>>>> interface that is unique to us.
> > >>>>>
> > >>>>> It also allows a lower barrier for new contributors for
> understanding
> > >>>>> existing code
> > >>>>>
> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > >>> [hidden email]
> > >>>>>
> > >>>>> wrote:
> > >>>>>
> > >>>>>> Hi Igniters,
> > >>>>>>
> > >>>>>> I'd like to start a discussion about replacing our custom
> > >>> IgniteFuture
> > >>>>>> class with CompletableFuture - existed JDK class
> > >>>>>> or rework it's implementation (like some other products done) to a
> > >>>>>> composition of CompletionStage and Future interfaces.
> > >>>>>> or maybe other option if you have any ideas. Do you?
> > >>>>>>
> > >>>>>> 1. The first approach pros and cons are
> > >>>>>> + Well-known JDK class
> > >>>>>> + Already implemented
> > >>>>>> - It is a class, not an interface.
> > >>>>>> - Expose some potentially harmful methods like "complete()".
> > >>>>>>
> > >>>>>> On the other side, it has copy() method to create defensive copy
> > >> and
> > >>>>>> minimalCompletionStage() to restrict harmful method usage.
> > >>>>>> Thus, this look like an applicable solution, but we should be
> > >> careful
> > >>>>>> exposing internal future to the outside.
> > >>>>>>
> > >>>>>> 2. The second approach is to implement our own interface like the
> > >>> next
> > >>>>> one:
> > >>>>>>
> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>, Future<T> {
> > >>>>>> }
> > >>>>>>
> > >>>>>> Pros and cons are
> > >>>>>> + Our interfaces/classes contracts will expose an interface rather
> > >>> than
> > >>>>>> concrete implementation.
> > >>>>>> + All methods are safe.
> > >>>>>> - Some implementation is required.
> > >>>>>> - CompletableStage has a method toCompletableFuture() and can be
> > >>>>> converted
> > >>>>>> to CompletableFuture. This should be supported.
> > >>>>>>
> > >>>>>> However, we still could wrap CompletableFuture and don't bother
> > >> about
> > >>>>>> creating a defensive copy.
> > >>>>>>
> > >>>>>>
> > >>>>>> Other project experience:
> > >>>>>> * Spotify uses CompletableFuture directly [1].
> > >>>>>> * Redis goes the second approach [2]
> > >>>>>> * Vertx explicitly extends CompletableFuture [3]. However, they
> > >> have
> > >>>>> custom
> > >>>>>> future classes and a number of helpers that could be replaced with
> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> > >>>>>>
> > >>>>>> Any thoughts?
> > >>>>>>
> > >>>>>> [1]
> > >>>>>>
> > >>>>>>
> > >>>>>
> > >>>>
> > >>>
> > >>
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > >>>>>> [2]
> > >>>>>>
> > >>>>>>
> > >>>>>
> > >>>>
> > >>>
> > >>
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > >>>>>> [3]
> > >>>>>>
> > >>>>>>
> > >>>>>
> > >>>>
> > >>>
> > >>
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > >>>>>> --
> > >>>>>> Best regards,
> > >>>>>> Andrey V. Mashenkov
> > >>>>>>
> > >>>>>
> > >>>>
> > >>>>
> > >>>> --
> > >>>>
> > >>>> Best regards,
> > >>>> Alexei Scherbakov
> > >>>>
> > >>>
> > >>
> > >>
> > >> --
> > >> Best regards,
> > >> Alexey
> > >>
> >
> >
>
> --
> Best regards,
> Andrey V. Mashenkov
>

[Ivan Pavlukhin]

> The methods below shouldn't be accessible for user:
> complete()
> completeExceptionaly()

Folks, in case of user-facing API, do you think there is a real harm
in allowing a user to manually "complete" a future? I suppose a user
employs some post-processing for future results and potentially wants
to have control of these results as well. E.g. premature completion in
case when a result is no longer needed is possible usage.

Also I thinkg it might be a good time to ponder about Future/Promise
APIs in general. Why such API is our choice? Can we choose e.g.
Reactive API style instead?

2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <[hidden email]>:

> Andrey,
>
> I see. So in a nutshell, you're saying that we want to return a future that
> the user's code is not allowed to complete. In this case, I think it's
> clear that CompletableFuture is not what we need. We actually need a
> NonCompletableFuture :)
>
> My vote is for the custom interface.
>
> -Val
>
> On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> <[hidden email]>
> wrote:
>
>> Val,
>>
>> The methods below shouldn't be accessible for user:
>> complete()
>> completeExceptionaly()
>>
>> Returning CompletableFuture we must always make a copy to prevent the
>> original future from being completed by mistake.
>> I think it will NOT be enough to do that returing the future to the
>> end-user, but from every critical module to the outside of the module,
>> e.g. to plugins. The impact of disclosing ExchangeFuture,
>> PartitionReleaseFuture to plugins may be serious.
>>
>> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
>> implementation
>> will just wrap CompletableFuture these issues will be resolved in natural
>> way.
>> In addition we can force toCompletableFuture() method to return a
>> defensive
>> copy(), that resolves the last concern.
>>
>>
>> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov <[hidden email]>
>> wrote:
>>
>> > CompletableFuture seems a better option to me.
>> >
>> > --
>> > Regards,
>> > Konstantin Orlov
>> >
>> >
>> >
>> >
>> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <[hidden email]>
>> > > wrote:
>> > >
>> > > On the one hand, I agree with Alexey.
>> > > CompletableFuture has complete* methods which should not be available
>> to
>> > > the user code.
>> > > This can be solved with a simple interface like we do in Thin Client:
>> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
>> > >
>> > >
>> > > On the other hand:
>> > > - CompletionStage has toCompletableFuture anyway (rather weird)
>> > > - Other libraries use CompletableFuture and it seems to be fine
>> > > - Using CompletableFuture is the simplest approach
>> > >
>> > >
>> > > So I lean towards CompletableFuture too.
>> > >
>> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
>> > [hidden email]>
>> > > wrote:
>> > >
>> > >> I do not like Java's CompletableFuture and prefer our own Future
>> > (revised
>> > >> IgniteFuture).
>> > >>
>> > >> My understanding of the Future (or Promise) pattern in general is
>> having
>> > >> two separate APIs:
>> > >>
>> > >>   1. Server-side: create, set result, raise error, cancel from
>> > >> server.
>> > >>   2. Client-side: get result, handle error, cancel from client
>> > >>
>> > >> Java's CompletableFuture looks like both the client-side and
>> > >> server-side API. The "Completeable" prefix in the name is already
>> > confusing
>> > >> for a client since it cannot "complete" an operation, only a server
>> can.
>> > >>
>> > >> I would create our own IgniteFuture adding client-side functionality
>> we
>> > >> currently miss (like client-side cancellation).
>> > >>
>> > >>
>> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
>> > >> [hidden email]>:
>> > >>
>> > >>> Andrey,
>> > >>>
>> > >>> Can you compile a full list of these risky methods, and elaborate
>> > >>> on
>> > what
>> > >>> the risks are?
>> > >>>
>> > >>> Generally, CompletableFuture is a much better option, because it's
>> > >>> standard. But we need to make sure it actually fits our needs and
>> > doesn't
>> > >>> do more harm than good.
>> > >>>
>> > >>> -Val
>> > >>>
>> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
>> > >>> [hidden email]> wrote:
>> > >>>
>> > >>>> I think both options are fine, but personally lean toward
>> > >>>> CompletableFuture.
>> > >>>>
>> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
>> > >>>>
>> > >>>>> I would suggest using CompletableFuture -- I don't see a need for
>> > >>>>> a
>> > >>>> custom
>> > >>>>> interface that is unique to us.
>> > >>>>>
>> > >>>>> It also allows a lower barrier for new contributors for
>> understanding
>> > >>>>> existing code
>> > >>>>>
>> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
>> > >>> [hidden email]
>> > >>>>>
>> > >>>>> wrote:
>> > >>>>>
>> > >>>>>> Hi Igniters,
>> > >>>>>>
>> > >>>>>> I'd like to start a discussion about replacing our custom
>> > >>> IgniteFuture
>> > >>>>>> class with CompletableFuture - existed JDK class
>> > >>>>>> or rework it's implementation (like some other products done) to
>> > >>>>>> a
>> > >>>>>> composition of CompletionStage and Future interfaces.
>> > >>>>>> or maybe other option if you have any ideas. Do you?
>> > >>>>>>
>> > >>>>>> 1. The first approach pros and cons are
>> > >>>>>> + Well-known JDK class
>> > >>>>>> + Already implemented
>> > >>>>>> - It is a class, not an interface.
>> > >>>>>> - Expose some potentially harmful methods like "complete()".
>> > >>>>>>
>> > >>>>>> On the other side, it has copy() method to create defensive copy
>> > >> and
>> > >>>>>> minimalCompletionStage() to restrict harmful method usage.
>> > >>>>>> Thus, this look like an applicable solution, but we should be
>> > >> careful
>> > >>>>>> exposing internal future to the outside.
>> > >>>>>>
>> > >>>>>> 2. The second approach is to implement our own interface like
>> > >>>>>> the
>> > >>> next
>> > >>>>> one:
>> > >>>>>>
>> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>, Future<T>
>> > >>>>>> {
>> > >>>>>> }
>> > >>>>>>
>> > >>>>>> Pros and cons are
>> > >>>>>> + Our interfaces/classes contracts will expose an interface
>> > >>>>>> rather
>> > >>> than
>> > >>>>>> concrete implementation.
>> > >>>>>> + All methods are safe.
>> > >>>>>> - Some implementation is required.
>> > >>>>>> - CompletableStage has a method toCompletableFuture() and can be
>> > >>>>> converted
>> > >>>>>> to CompletableFuture. This should be supported.
>> > >>>>>>
>> > >>>>>> However, we still could wrap CompletableFuture and don't bother
>> > >> about
>> > >>>>>> creating a defensive copy.
>> > >>>>>>
>> > >>>>>>
>> > >>>>>> Other project experience:
>> > >>>>>> * Spotify uses CompletableFuture directly [1].
>> > >>>>>> * Redis goes the second approach [2]
>> > >>>>>> * Vertx explicitly extends CompletableFuture [3]. However, they
>> > >> have
>> > >>>>> custom
>> > >>>>>> future classes and a number of helpers that could be replaced
>> > >>>>>> with
>> > >>>>>> CompletableStage. Maybe it is just a legacy.'
>> > >>>>>>
>> > >>>>>> Any thoughts?
>> > >>>>>>
>> > >>>>>> [1]
>> > >>>>>>
>> > >>>>>>
>> > >>>>>
>> > >>>>
>> > >>>
>> > >>
>> >
>> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
>> > >>>>>> [2]
>> > >>>>>>
>> > >>>>>>
>> > >>>>>
>> > >>>>
>> > >>>
>> > >>
>> >
>> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
>> > >>>>>> [3]
>> > >>>>>>
>> > >>>>>>
>> > >>>>>
>> > >>>>
>> > >>>
>> > >>
>> >
>> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
>> > >>>>>> --
>> > >>>>>> Best regards,
>> > >>>>>> Andrey V. Mashenkov
>> > >>>>>>
>> > >>>>>
>> > >>>>
>> > >>>>
>> > >>>> --
>> > >>>>
>> > >>>> Best regards,
>> > >>>> Alexei Scherbakov
>> > >>>>
>> > >>>
>> > >>
>> > >>
>> > >> --
>> > >> Best regards,
>> > >> Alexey
>> > >>
>> >
>> >
>>
>> --
>> Best regards,
>> Andrey V. Mashenkov
>>
>

--

Best regards,
Ivan Pavlukhin

[Valentin Kulichenko]

Ivan,

It's not really about the "harm", but more about "what should we do if this
method is called?". Imagine the following code:

CompletableFuture<String> fut = cache.getAsync(key);
fut.complete("something");

What should happen in this case?

The point is that currently a future returned from any of Ignite's async
operations is supposed to be completed with a value only by Ignite itself,
not by the user. If we follow the same approach in Ignite 3, returning
CompletableFuture is surely wrong in my view.

At the same time, if we take a fundamentally different route with the async
APIs, this whole discussion might become irrelevant. For example, can you
elaborate on your thinking around the reactive API? Do you have any
specifics in mind?

-Val

On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <[hidden email]> wrote:

> > The methods below shouldn't be accessible for user:
> > complete()
> > completeExceptionaly()
>
> Folks, in case of user-facing API, do you think there is a real harm
> in allowing a user to manually "complete" a future? I suppose a user
> employs some post-processing for future results and potentially wants
> to have control of these results as well. E.g. premature completion in
> case when a result is no longer needed is possible usage.
>
> Also I thinkg it might be a good time to ponder about Future/Promise
> APIs in general. Why such API is our choice? Can we choose e.g.
> Reactive API style instead?
>
> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> [hidden email]>:
> > Andrey,
> >
> > I see. So in a nutshell, you're saying that we want to return a future
> that
> > the user's code is not allowed to complete. In this case, I think it's
> > clear that CompletableFuture is not what we need. We actually need a
> > NonCompletableFuture :)
> >
> > My vote is for the custom interface.
> >
> > -Val
> >
> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> > <[hidden email]>
> > wrote:
> >
> >> Val,
> >>
> >> The methods below shouldn't be accessible for user:
> >> complete()
> >> completeExceptionaly()
> >>
> >> Returning CompletableFuture we must always make a copy to prevent the
> >> original future from being completed by mistake.
> >> I think it will NOT be enough to do that returing the future to the
> >> end-user, but from every critical module to the outside of the module,
> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> >> PartitionReleaseFuture to plugins may be serious.
> >>
> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
> >> implementation
> >> will just wrap CompletableFuture these issues will be resolved in
> natural
> >> way.
> >> In addition we can force toCompletableFuture() method to return a
> >> defensive
> >> copy(), that resolves the last concern.
> >>
> >>
> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov <[hidden email]>
> >> wrote:
> >>
> >> > CompletableFuture seems a better option to me.
> >> >
> >> > --
> >> > Regards,
> >> > Konstantin Orlov
> >> >
> >> >
> >> >
> >> >
> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <[hidden email]>
> >> > > wrote:
> >> > >
> >> > > On the one hand, I agree with Alexey.
> >> > > CompletableFuture has complete* methods which should not be
> available
> >> to
> >> > > the user code.
> >> > > This can be solved with a simple interface like we do in Thin
> Client:
> >> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
> >> > >
> >> > >
> >> > > On the other hand:
> >> > > - CompletionStage has toCompletableFuture anyway (rather weird)
> >> > > - Other libraries use CompletableFuture and it seems to be fine
> >> > > - Using CompletableFuture is the simplest approach
> >> > >
> >> > >
> >> > > So I lean towards CompletableFuture too.
> >> > >
> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> >> > [hidden email]>
> >> > > wrote:
> >> > >
> >> > >> I do not like Java's CompletableFuture and prefer our own Future
> >> > (revised
> >> > >> IgniteFuture).
> >> > >>
> >> > >> My understanding of the Future (or Promise) pattern in general is
> >> having
> >> > >> two separate APIs:
> >> > >>
> >> > >>   1. Server-side: create, set result, raise error, cancel from
> >> > >> server.
> >> > >>   2. Client-side: get result, handle error, cancel from client
> >> > >>
> >> > >> Java's CompletableFuture looks like both the client-side and
> >> > >> server-side API. The "Completeable" prefix in the name is already
> >> > confusing
> >> > >> for a client since it cannot "complete" an operation, only a server
> >> can.
> >> > >>
> >> > >> I would create our own IgniteFuture adding client-side
> functionality
> >> we
> >> > >> currently miss (like client-side cancellation).
> >> > >>
> >> > >>
> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> >> > >> [hidden email]>:
> >> > >>
> >> > >>> Andrey,
> >> > >>>
> >> > >>> Can you compile a full list of these risky methods, and elaborate
> >> > >>> on
> >> > what
> >> > >>> the risks are?
> >> > >>>
> >> > >>> Generally, CompletableFuture is a much better option, because it's
> >> > >>> standard. But we need to make sure it actually fits our needs and
> >> > doesn't
> >> > >>> do more harm than good.
> >> > >>>
> >> > >>> -Val
> >> > >>>
> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> >> > >>> [hidden email]> wrote:
> >> > >>>
> >> > >>>> I think both options are fine, but personally lean toward
> >> > >>>> CompletableFuture.
> >> > >>>>
> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
> >> > >>>>
> >> > >>>>> I would suggest using CompletableFuture -- I don't see a need
> for
> >> > >>>>> a
> >> > >>>> custom
> >> > >>>>> interface that is unique to us.
> >> > >>>>>
> >> > >>>>> It also allows a lower barrier for new contributors for
> >> understanding
> >> > >>>>> existing code
> >> > >>>>>
> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> >> > >>> [hidden email]
> >> > >>>>>
> >> > >>>>> wrote:
> >> > >>>>>
> >> > >>>>>> Hi Igniters,
> >> > >>>>>>
> >> > >>>>>> I'd like to start a discussion about replacing our custom
> >> > >>> IgniteFuture
> >> > >>>>>> class with CompletableFuture - existed JDK class
> >> > >>>>>> or rework it's implementation (like some other products done)
> to
> >> > >>>>>> a
> >> > >>>>>> composition of CompletionStage and Future interfaces.
> >> > >>>>>> or maybe other option if you have any ideas. Do you?
> >> > >>>>>>
> >> > >>>>>> 1. The first approach pros and cons are
> >> > >>>>>> + Well-known JDK class
> >> > >>>>>> + Already implemented
> >> > >>>>>> - It is a class, not an interface.
> >> > >>>>>> - Expose some potentially harmful methods like "complete()".
> >> > >>>>>>
> >> > >>>>>> On the other side, it has copy() method to create defensive
> copy
> >> > >> and
> >> > >>>>>> minimalCompletionStage() to restrict harmful method usage.
> >> > >>>>>> Thus, this look like an applicable solution, but we should be
> >> > >> careful
> >> > >>>>>> exposing internal future to the outside.
> >> > >>>>>>
> >> > >>>>>> 2. The second approach is to implement our own interface like
> >> > >>>>>> the
> >> > >>> next
> >> > >>>>> one:
> >> > >>>>>>
> >> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>,
> Future<T>
> >> > >>>>>> {
> >> > >>>>>> }
> >> > >>>>>>
> >> > >>>>>> Pros and cons are
> >> > >>>>>> + Our interfaces/classes contracts will expose an interface
> >> > >>>>>> rather
> >> > >>> than
> >> > >>>>>> concrete implementation.
> >> > >>>>>> + All methods are safe.
> >> > >>>>>> - Some implementation is required.
> >> > >>>>>> - CompletableStage has a method toCompletableFuture() and can
> be
> >> > >>>>> converted
> >> > >>>>>> to CompletableFuture. This should be supported.
> >> > >>>>>>
> >> > >>>>>> However, we still could wrap CompletableFuture and don't bother
> >> > >> about
> >> > >>>>>> creating a defensive copy.
> >> > >>>>>>
> >> > >>>>>>
> >> > >>>>>> Other project experience:
> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> >> > >>>>>> * Redis goes the second approach [2]
> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3]. However, they
> >> > >> have
> >> > >>>>> custom
> >> > >>>>>> future classes and a number of helpers that could be replaced
> >> > >>>>>> with
> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> >> > >>>>>>
> >> > >>>>>> Any thoughts?
> >> > >>>>>>
> >> > >>>>>> [1]
> >> > >>>>>>
> >> > >>>>>>
> >> > >>>>>
> >> > >>>>
> >> > >>>
> >> > >>
> >> >
> >>
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> >> > >>>>>> [2]
> >> > >>>>>>
> >> > >>>>>>
> >> > >>>>>
> >> > >>>>
> >> > >>>
> >> > >>
> >> >
> >>
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> >> > >>>>>> [3]
> >> > >>>>>>
> >> > >>>>>>
> >> > >>>>>
> >> > >>>>
> >> > >>>
> >> > >>
> >> >
> >>
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> >> > >>>>>> --
> >> > >>>>>> Best regards,
> >> > >>>>>> Andrey V. Mashenkov
> >> > >>>>>>
> >> > >>>>>
> >> > >>>>
> >> > >>>>
> >> > >>>> --
> >> > >>>>
> >> > >>>> Best regards,
> >> > >>>> Alexei Scherbakov
> >> > >>>>
> >> > >>>
> >> > >>
> >> > >>
> >> > >> --
> >> > >> Best regards,
> >> > >> Alexey
> >> > >>
> >> >
> >> >
> >>
> >> --
> >> Best regards,
> >> Andrey V. Mashenkov
> >>
> >
>
>
> --
>
> Best regards,
> Ivan Pavlukhin
>

[Ivan Pavlukhin]

Val,

There were enough hype around Reactive programming past years. I
remind a lot of talks about RxJava. And I suppose it worth to consider
it. But it requires some time to study modern trends to make a choice.
So far I am not ready to facilitate Reactive API for Ignite 3.

Regarding CompletableFuture.

> The point is that currently a future returned from any of Ignite's async
> operations is supposed to be completed with a value only by Ignite itself,
> not by the user. If we follow the same approach in Ignite 3, returning
> CompletableFuture is surely wrong in my view.

My first thoughts was similar. But later I thought what a user would
like do with returned future. And one of cases I imagined was a case
of alternative result. E.g. a user uses Ignite and another data source
in his application. He wants to use a value arrived faster. He
combines 2 futures like CompletableFuture.anyOf(...). Consequently
even if we prohibit CompletableFuture.complete(...) explicitly then it
will be possible to create a combination that will allow premature
future completion. After all generally CompletableFuture is a
placeholder for async computaion result and if a user wants to
substitute result returned from Ignite why should we disallow him to
do it?

Also I found one more suspicious thing with CompletableFuture. As it
is a concrete class it implements a cancel() method. And as I see the
implementation does not try to cancel underlying computations. Is not
it a problem?

2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <[hidden email]>:

> Ivan,
>
> It's not really about the "harm", but more about "what should we do if this
> method is called?". Imagine the following code:
>
> CompletableFuture<String> fut = cache.getAsync(key);
> fut.complete("something");
>
> What should happen in this case?
>
> The point is that currently a future returned from any of Ignite's async
> operations is supposed to be completed with a value only by Ignite itself,
> not by the user. If we follow the same approach in Ignite 3, returning
> CompletableFuture is surely wrong in my view.
>
> At the same time, if we take a fundamentally different route with the async
> APIs, this whole discussion might become irrelevant. For example, can you
> elaborate on your thinking around the reactive API? Do you have any
> specifics in mind?
>
> -Val
>
> On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <[hidden email]> wrote:
>
>> > The methods below shouldn't be accessible for user:
>> > complete()
>> > completeExceptionaly()
>>
>> Folks, in case of user-facing API, do you think there is a real harm
>> in allowing a user to manually "complete" a future? I suppose a user
>> employs some post-processing for future results and potentially wants
>> to have control of these results as well. E.g. premature completion in
>> case when a result is no longer needed is possible usage.
>>
>> Also I thinkg it might be a good time to ponder about Future/Promise
>> APIs in general. Why such API is our choice? Can we choose e.g.
>> Reactive API style instead?
>>
>> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
>> [hidden email]>:
>> > Andrey,
>> >
>> > I see. So in a nutshell, you're saying that we want to return a future
>> that
>> > the user's code is not allowed to complete. In this case, I think it's
>> > clear that CompletableFuture is not what we need. We actually need a
>> > NonCompletableFuture :)
>> >
>> > My vote is for the custom interface.
>> >
>> > -Val
>> >
>> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
>> > <[hidden email]>
>> > wrote:
>> >
>> >> Val,
>> >>
>> >> The methods below shouldn't be accessible for user:
>> >> complete()
>> >> completeExceptionaly()
>> >>
>> >> Returning CompletableFuture we must always make a copy to prevent the
>> >> original future from being completed by mistake.
>> >> I think it will NOT be enough to do that returing the future to the
>> >> end-user, but from every critical module to the outside of the module,
>> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
>> >> PartitionReleaseFuture to plugins may be serious.
>> >>
>> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
>> >> implementation
>> >> will just wrap CompletableFuture these issues will be resolved in
>> natural
>> >> way.
>> >> In addition we can force toCompletableFuture() method to return a
>> >> defensive
>> >> copy(), that resolves the last concern.
>> >>
>> >>
>> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
>> >> <[hidden email]>
>> >> wrote:
>> >>
>> >> > CompletableFuture seems a better option to me.
>> >> >
>> >> > --
>> >> > Regards,
>> >> > Konstantin Orlov
>> >> >
>> >> >
>> >> >
>> >> >
>> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <[hidden email]>
>> >> > > wrote:
>> >> > >
>> >> > > On the one hand, I agree with Alexey.
>> >> > > CompletableFuture has complete* methods which should not be
>> available
>> >> to
>> >> > > the user code.
>> >> > > This can be solved with a simple interface like we do in Thin
>> Client:
>> >> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
>> >> > >
>> >> > >
>> >> > > On the other hand:
>> >> > > - CompletionStage has toCompletableFuture anyway (rather weird)
>> >> > > - Other libraries use CompletableFuture and it seems to be fine
>> >> > > - Using CompletableFuture is the simplest approach
>> >> > >
>> >> > >
>> >> > > So I lean towards CompletableFuture too.
>> >> > >
>> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
>> >> > [hidden email]>
>> >> > > wrote:
>> >> > >
>> >> > >> I do not like Java's CompletableFuture and prefer our own Future
>> >> > (revised
>> >> > >> IgniteFuture).
>> >> > >>
>> >> > >> My understanding of the Future (or Promise) pattern in general is
>> >> having
>> >> > >> two separate APIs:
>> >> > >>
>> >> > >>   1. Server-side: create, set result, raise error, cancel from
>> >> > >> server.
>> >> > >>   2. Client-side: get result, handle error, cancel from client
>> >> > >>
>> >> > >> Java's CompletableFuture looks like both the client-side and
>> >> > >> server-side API. The "Completeable" prefix in the name is already
>> >> > confusing
>> >> > >> for a client since it cannot "complete" an operation, only a
>> >> > >> server
>> >> can.
>> >> > >>
>> >> > >> I would create our own IgniteFuture adding client-side
>> functionality
>> >> we
>> >> > >> currently miss (like client-side cancellation).
>> >> > >>
>> >> > >>
>> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
>> >> > >> [hidden email]>:
>> >> > >>
>> >> > >>> Andrey,
>> >> > >>>
>> >> > >>> Can you compile a full list of these risky methods, and
>> >> > >>> elaborate
>> >> > >>> on
>> >> > what
>> >> > >>> the risks are?
>> >> > >>>
>> >> > >>> Generally, CompletableFuture is a much better option, because
>> >> > >>> it's
>> >> > >>> standard. But we need to make sure it actually fits our needs
>> >> > >>> and
>> >> > doesn't
>> >> > >>> do more harm than good.
>> >> > >>>
>> >> > >>> -Val
>> >> > >>>
>> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
>> >> > >>> [hidden email]> wrote:
>> >> > >>>
>> >> > >>>> I think both options are fine, but personally lean toward
>> >> > >>>> CompletableFuture.
>> >> > >>>>
>> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
>> >> > >>>>
>> >> > >>>>> I would suggest using CompletableFuture -- I don't see a need
>> for
>> >> > >>>>> a
>> >> > >>>> custom
>> >> > >>>>> interface that is unique to us.
>> >> > >>>>>
>> >> > >>>>> It also allows a lower barrier for new contributors for
>> >> understanding
>> >> > >>>>> existing code
>> >> > >>>>>
>> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
>> >> > >>> [hidden email]
>> >> > >>>>>
>> >> > >>>>> wrote:
>> >> > >>>>>
>> >> > >>>>>> Hi Igniters,
>> >> > >>>>>>
>> >> > >>>>>> I'd like to start a discussion about replacing our custom
>> >> > >>> IgniteFuture
>> >> > >>>>>> class with CompletableFuture - existed JDK class
>> >> > >>>>>> or rework it's implementation (like some other products done)
>> to
>> >> > >>>>>> a
>> >> > >>>>>> composition of CompletionStage and Future interfaces.
>> >> > >>>>>> or maybe other option if you have any ideas. Do you?
>> >> > >>>>>>
>> >> > >>>>>> 1. The first approach pros and cons are
>> >> > >>>>>> + Well-known JDK class
>> >> > >>>>>> + Already implemented
>> >> > >>>>>> - It is a class, not an interface.
>> >> > >>>>>> - Expose some potentially harmful methods like "complete()".
>> >> > >>>>>>
>> >> > >>>>>> On the other side, it has copy() method to create defensive
>> copy
>> >> > >> and
>> >> > >>>>>> minimalCompletionStage() to restrict harmful method usage.
>> >> > >>>>>> Thus, this look like an applicable solution, but we should be
>> >> > >> careful
>> >> > >>>>>> exposing internal future to the outside.
>> >> > >>>>>>
>> >> > >>>>>> 2. The second approach is to implement our own interface like
>> >> > >>>>>> the
>> >> > >>> next
>> >> > >>>>> one:
>> >> > >>>>>>
>> >> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>,
>> Future<T>
>> >> > >>>>>> {
>> >> > >>>>>> }
>> >> > >>>>>>
>> >> > >>>>>> Pros and cons are
>> >> > >>>>>> + Our interfaces/classes contracts will expose an interface
>> >> > >>>>>> rather
>> >> > >>> than
>> >> > >>>>>> concrete implementation.
>> >> > >>>>>> + All methods are safe.
>> >> > >>>>>> - Some implementation is required.
>> >> > >>>>>> - CompletableStage has a method toCompletableFuture() and can
>> be
>> >> > >>>>> converted
>> >> > >>>>>> to CompletableFuture. This should be supported.
>> >> > >>>>>>
>> >> > >>>>>> However, we still could wrap CompletableFuture and don't
>> >> > >>>>>> bother
>> >> > >> about
>> >> > >>>>>> creating a defensive copy.
>> >> > >>>>>>
>> >> > >>>>>>
>> >> > >>>>>> Other project experience:
>> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
>> >> > >>>>>> * Redis goes the second approach [2]
>> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3]. However,
>> >> > >>>>>> they
>> >> > >> have
>> >> > >>>>> custom
>> >> > >>>>>> future classes and a number of helpers that could be replaced
>> >> > >>>>>> with
>> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
>> >> > >>>>>>
>> >> > >>>>>> Any thoughts?
>> >> > >>>>>>
>> >> > >>>>>> [1]
>> >> > >>>>>>
>> >> > >>>>>>
>> >> > >>>>>
>> >> > >>>>
>> >> > >>>
>> >> > >>
>> >> >
>> >>
>> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
>> >> > >>>>>> [2]
>> >> > >>>>>>
>> >> > >>>>>>
>> >> > >>>>>
>> >> > >>>>
>> >> > >>>
>> >> > >>
>> >> >
>> >>
>> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
>> >> > >>>>>> [3]
>> >> > >>>>>>
>> >> > >>>>>>
>> >> > >>>>>
>> >> > >>>>
>> >> > >>>
>> >> > >>
>> >> >
>> >>
>> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
>> >> > >>>>>> --
>> >> > >>>>>> Best regards,
>> >> > >>>>>> Andrey V. Mashenkov
>> >> > >>>>>>
>> >> > >>>>>
>> >> > >>>>
>> >> > >>>>
>> >> > >>>> --
>> >> > >>>>
>> >> > >>>> Best regards,
>> >> > >>>> Alexei Scherbakov
>> >> > >>>>
>> >> > >>>
>> >> > >>
>> >> > >>
>> >> > >> --
>> >> > >> Best regards,
>> >> > >> Alexey
>> >> > >>
>> >> >
>> >> >
>> >>
>> >> --
>> >> Best regards,
>> >> Andrey V. Mashenkov
>> >>
>> >
>>
>>
>> --
>>
>> Best regards,
>> Ivan Pavlukhin
>>
>

--

Best regards,
Ivan Pavlukhin

[Alexey Goncharuk]

Ivan,

My concern with the concept of a user completing the future returned from
Ignite public API is that it is unclear how to interpret this action (this
backs Val's message).
Let's say a user started a compute with fut = compute.runAsync(task); and
now calls fut.complete(someVal); Does this mean that Ignite no longer needs
to execute the task? If the task is currently running, does it need to be
canceled?

Using CompletableFuture.anyOf() is a good instrument in this case because
it makes the 'first future wins' contract explicit in the code. Besides
that, the point regarding the cancel() method is valid, and we will need
some custom mechanics to cancel a computation, so a custom interface that
simply extends both Future and CompletableStage seems reasonable to me.

--AG

пн, 29 мар. 2021 г. в 09:12, Ivan Pavlukhin <[hidden email]>:

> Val,
>
> There were enough hype around Reactive programming past years. I
> remind a lot of talks about RxJava. And I suppose it worth to consider
> it. But it requires some time to study modern trends to make a choice.
> So far I am not ready to facilitate Reactive API for Ignite 3.
>
> Regarding CompletableFuture.
>
> > The point is that currently a future returned from any of Ignite's async
> > operations is supposed to be completed with a value only by Ignite
> itself,
> > not by the user. If we follow the same approach in Ignite 3, returning
> > CompletableFuture is surely wrong in my view.
>
> My first thoughts was similar. But later I thought what a user would
> like do with returned future. And one of cases I imagined was a case
> of alternative result. E.g. a user uses Ignite and another data source
> in his application. He wants to use a value arrived faster. He
> combines 2 futures like CompletableFuture.anyOf(...). Consequently
> even if we prohibit CompletableFuture.complete(...) explicitly then it
> will be possible to create a combination that will allow premature
> future completion. After all generally CompletableFuture is a
> placeholder for async computaion result and if a user wants to
> substitute result returned from Ignite why should we disallow him to
> do it?
>
> Also I found one more suspicious thing with CompletableFuture. As it
> is a concrete class it implements a cancel() method. And as I see the
> implementation does not try to cancel underlying computations. Is not
> it a problem?
>
> 2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <
> [hidden email]>:
> > Ivan,
> >
> > It's not really about the "harm", but more about "what should we do if
> this
> > method is called?". Imagine the following code:
> >
> > CompletableFuture<String> fut = cache.getAsync(key);
> > fut.complete("something");
> >
> > What should happen in this case?
> >
> > The point is that currently a future returned from any of Ignite's async
> > operations is supposed to be completed with a value only by Ignite
> itself,
> > not by the user. If we follow the same approach in Ignite 3, returning
> > CompletableFuture is surely wrong in my view.
> >
> > At the same time, if we take a fundamentally different route with the
> async
> > APIs, this whole discussion might become irrelevant. For example, can you
> > elaborate on your thinking around the reactive API? Do you have any
> > specifics in mind?
> >
> > -Val
> >
> > On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <[hidden email]>
> wrote:
> >
> >> > The methods below shouldn't be accessible for user:
> >> > complete()
> >> > completeExceptionaly()
> >>
> >> Folks, in case of user-facing API, do you think there is a real harm
> >> in allowing a user to manually "complete" a future? I suppose a user
> >> employs some post-processing for future results and potentially wants
> >> to have control of these results as well. E.g. premature completion in
> >> case when a result is no longer needed is possible usage.
> >>
> >> Also I thinkg it might be a good time to ponder about Future/Promise
> >> APIs in general. Why such API is our choice? Can we choose e.g.
> >> Reactive API style instead?
> >>
> >> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> >> [hidden email]>:
> >> > Andrey,
> >> >
> >> > I see. So in a nutshell, you're saying that we want to return a future
> >> that
> >> > the user's code is not allowed to complete. In this case, I think it's
> >> > clear that CompletableFuture is not what we need. We actually need a
> >> > NonCompletableFuture :)
> >> >
> >> > My vote is for the custom interface.
> >> >
> >> > -Val
> >> >
> >> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> >> > <[hidden email]>
> >> > wrote:
> >> >
> >> >> Val,
> >> >>
> >> >> The methods below shouldn't be accessible for user:
> >> >> complete()
> >> >> completeExceptionaly()
> >> >>
> >> >> Returning CompletableFuture we must always make a copy to prevent the
> >> >> original future from being completed by mistake.
> >> >> I think it will NOT be enough to do that returing the future to the
> >> >> end-user, but from every critical module to the outside of the
> module,
> >> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> >> >> PartitionReleaseFuture to plugins may be serious.
> >> >>
> >> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
> >> >> implementation
> >> >> will just wrap CompletableFuture these issues will be resolved in
> >> natural
> >> >> way.
> >> >> In addition we can force toCompletableFuture() method to return a
> >> >> defensive
> >> >> copy(), that resolves the last concern.
> >> >>
> >> >>
> >> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
> >> >> <[hidden email]>
> >> >> wrote:
> >> >>
> >> >> > CompletableFuture seems a better option to me.
> >> >> >
> >> >> > --
> >> >> > Regards,
> >> >> > Konstantin Orlov
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <[hidden email]>
> >> >> > > wrote:
> >> >> > >
> >> >> > > On the one hand, I agree with Alexey.
> >> >> > > CompletableFuture has complete* methods which should not be
> >> available
> >> >> to
> >> >> > > the user code.
> >> >> > > This can be solved with a simple interface like we do in Thin
> >> Client:
> >> >> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
> >> >> > >
> >> >> > >
> >> >> > > On the other hand:
> >> >> > > - CompletionStage has toCompletableFuture anyway (rather weird)
> >> >> > > - Other libraries use CompletableFuture and it seems to be fine
> >> >> > > - Using CompletableFuture is the simplest approach
> >> >> > >
> >> >> > >
> >> >> > > So I lean towards CompletableFuture too.
> >> >> > >
> >> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> >> >> > [hidden email]>
> >> >> > > wrote:
> >> >> > >
> >> >> > >> I do not like Java's CompletableFuture and prefer our own Future
> >> >> > (revised
> >> >> > >> IgniteFuture).
> >> >> > >>
> >> >> > >> My understanding of the Future (or Promise) pattern in general
> is
> >> >> having
> >> >> > >> two separate APIs:
> >> >> > >>
> >> >> > >>   1. Server-side: create, set result, raise error, cancel from
> >> >> > >> server.
> >> >> > >>   2. Client-side: get result, handle error, cancel from client
> >> >> > >>
> >> >> > >> Java's CompletableFuture looks like both the client-side and
> >> >> > >> server-side API. The "Completeable" prefix in the name is
> already
> >> >> > confusing
> >> >> > >> for a client since it cannot "complete" an operation, only a
> >> >> > >> server
> >> >> can.
> >> >> > >>
> >> >> > >> I would create our own IgniteFuture adding client-side
> >> functionality
> >> >> we
> >> >> > >> currently miss (like client-side cancellation).
> >> >> > >>
> >> >> > >>
> >> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> >> >> > >> [hidden email]>:
> >> >> > >>
> >> >> > >>> Andrey,
> >> >> > >>>
> >> >> > >>> Can you compile a full list of these risky methods, and
> >> >> > >>> elaborate
> >> >> > >>> on
> >> >> > what
> >> >> > >>> the risks are?
> >> >> > >>>
> >> >> > >>> Generally, CompletableFuture is a much better option, because
> >> >> > >>> it's
> >> >> > >>> standard. But we need to make sure it actually fits our needs
> >> >> > >>> and
> >> >> > doesn't
> >> >> > >>> do more harm than good.
> >> >> > >>>
> >> >> > >>> -Val
> >> >> > >>>
> >> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> >> >> > >>> [hidden email]> wrote:
> >> >> > >>>
> >> >> > >>>> I think both options are fine, but personally lean toward
> >> >> > >>>> CompletableFuture.
> >> >> > >>>>
> >> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
> >> >> > >>>>
> >> >> > >>>>> I would suggest using CompletableFuture -- I don't see a need
> >> for
> >> >> > >>>>> a
> >> >> > >>>> custom
> >> >> > >>>>> interface that is unique to us.
> >> >> > >>>>>
> >> >> > >>>>> It also allows a lower barrier for new contributors for
> >> >> understanding
> >> >> > >>>>> existing code
> >> >> > >>>>>
> >> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> >> >> > >>> [hidden email]
> >> >> > >>>>>
> >> >> > >>>>> wrote:
> >> >> > >>>>>
> >> >> > >>>>>> Hi Igniters,
> >> >> > >>>>>>
> >> >> > >>>>>> I'd like to start a discussion about replacing our custom
> >> >> > >>> IgniteFuture
> >> >> > >>>>>> class with CompletableFuture - existed JDK class
> >> >> > >>>>>> or rework it's implementation (like some other products
> done)
> >> to
> >> >> > >>>>>> a
> >> >> > >>>>>> composition of CompletionStage and Future interfaces.
> >> >> > >>>>>> or maybe other option if you have any ideas. Do you?
> >> >> > >>>>>>
> >> >> > >>>>>> 1. The first approach pros and cons are
> >> >> > >>>>>> + Well-known JDK class
> >> >> > >>>>>> + Already implemented
> >> >> > >>>>>> - It is a class, not an interface.
> >> >> > >>>>>> - Expose some potentially harmful methods like "complete()".
> >> >> > >>>>>>
> >> >> > >>>>>> On the other side, it has copy() method to create defensive
> >> copy
> >> >> > >> and
> >> >> > >>>>>> minimalCompletionStage() to restrict harmful method usage.
> >> >> > >>>>>> Thus, this look like an applicable solution, but we should
> be
> >> >> > >> careful
> >> >> > >>>>>> exposing internal future to the outside.
> >> >> > >>>>>>
> >> >> > >>>>>> 2. The second approach is to implement our own interface
> like
> >> >> > >>>>>> the
> >> >> > >>> next
> >> >> > >>>>> one:
> >> >> > >>>>>>
> >> >> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>,
> >> Future<T>
> >> >> > >>>>>> {
> >> >> > >>>>>> }
> >> >> > >>>>>>
> >> >> > >>>>>> Pros and cons are
> >> >> > >>>>>> + Our interfaces/classes contracts will expose an interface
> >> >> > >>>>>> rather
> >> >> > >>> than
> >> >> > >>>>>> concrete implementation.
> >> >> > >>>>>> + All methods are safe.
> >> >> > >>>>>> - Some implementation is required.
> >> >> > >>>>>> - CompletableStage has a method toCompletableFuture() and
> can
> >> be
> >> >> > >>>>> converted
> >> >> > >>>>>> to CompletableFuture. This should be supported.
> >> >> > >>>>>>
> >> >> > >>>>>> However, we still could wrap CompletableFuture and don't
> >> >> > >>>>>> bother
> >> >> > >> about
> >> >> > >>>>>> creating a defensive copy.
> >> >> > >>>>>>
> >> >> > >>>>>>
> >> >> > >>>>>> Other project experience:
> >> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> >> >> > >>>>>> * Redis goes the second approach [2]
> >> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3]. However,
> >> >> > >>>>>> they
> >> >> > >> have
> >> >> > >>>>> custom
> >> >> > >>>>>> future classes and a number of helpers that could be
> replaced
> >> >> > >>>>>> with
> >> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> >> >> > >>>>>>
> >> >> > >>>>>> Any thoughts?
> >> >> > >>>>>>
> >> >> > >>>>>> [1]
> >> >> > >>>>>>
> >> >> > >>>>>>
> >> >> > >>>>>
> >> >> > >>>>
> >> >> > >>>
> >> >> > >>
> >> >> >
> >> >>
> >>
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> >> >> > >>>>>> [2]
> >> >> > >>>>>>
> >> >> > >>>>>>
> >> >> > >>>>>
> >> >> > >>>>
> >> >> > >>>
> >> >> > >>
> >> >> >
> >> >>
> >>
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> >> >> > >>>>>> [3]
> >> >> > >>>>>>
> >> >> > >>>>>>
> >> >> > >>>>>
> >> >> > >>>>
> >> >> > >>>
> >> >> > >>
> >> >> >
> >> >>
> >>
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> >> >> > >>>>>> --
> >> >> > >>>>>> Best regards,
> >> >> > >>>>>> Andrey V. Mashenkov
> >> >> > >>>>>>
> >> >> > >>>>>
> >> >> > >>>>
> >> >> > >>>>
> >> >> > >>>> --
> >> >> > >>>>
> >> >> > >>>> Best regards,
> >> >> > >>>> Alexei Scherbakov
> >> >> > >>>>
> >> >> > >>>
> >> >> > >>
> >> >> > >>
> >> >> > >> --
> >> >> > >> Best regards,
> >> >> > >> Alexey
> >> >> > >>
> >> >> >
> >> >> >
> >> >>
> >> >> --
> >> >> Best regards,
> >> >> Andrey V. Mashenkov
> >> >>
> >> >
> >>
> >>
> >> --
> >>
> >> Best regards,
> >> Ivan Pavlukhin
> >>
> >
>
>
> --
>
> Best regards,
> Ivan Pavlukhin
>

[Andrew Mashenkov]

Guys,

I want to remember there is one more point to pay attention to.
Extending Future and CompletableStage is more than just prevents unexpected
behavior if a user completed the future.

First of all, it helps us to write safer code as we won't a method contract
exposed such methods as to a user as to a developer.
If you look at Ignite-2 code, you may found a number of places where we
return e.g. exchange futures or partition release futures.
Assume the impact if we will return CompletableFuture instead, which can be
completed in 3-rd party plugin by mistake?

The suggested approach allows us to don't bother if a CompletableFuture has
to be wrapped or not.


On Tue, Mar 30, 2021 at 12:22 PM Alexey Goncharuk <
[hidden email]> wrote:

> Ivan,
>
> My concern with the concept of a user completing the future returned from
> Ignite public API is that it is unclear how to interpret this action (this
> backs Val's message).
> Let's say a user started a compute with fut = compute.runAsync(task); and
> now calls fut.complete(someVal); Does this mean that Ignite no longer needs
> to execute the task? If the task is currently running, does it need to be
> canceled?
>
> Using CompletableFuture.anyOf() is a good instrument in this case because
> it makes the 'first future wins' contract explicit in the code. Besides
> that, the point regarding the cancel() method is valid, and we will need
> some custom mechanics to cancel a computation, so a custom interface that
> simply extends both Future and CompletableStage seems reasonable to me.
>
> --AG
>
> пн, 29 мар. 2021 г. в 09:12, Ivan Pavlukhin <[hidden email]>:
>
> > Val,
> >
> > There were enough hype around Reactive programming past years. I
> > remind a lot of talks about RxJava. And I suppose it worth to consider
> > it. But it requires some time to study modern trends to make a choice.
> > So far I am not ready to facilitate Reactive API for Ignite 3.
> >
> > Regarding CompletableFuture.
> >
> > > The point is that currently a future returned from any of Ignite's
> async
> > > operations is supposed to be completed with a value only by Ignite
> > itself,
> > > not by the user. If we follow the same approach in Ignite 3, returning
> > > CompletableFuture is surely wrong in my view.
> >
> > My first thoughts was similar. But later I thought what a user would
> > like do with returned future. And one of cases I imagined was a case
> > of alternative result. E.g. a user uses Ignite and another data source
> > in his application. He wants to use a value arrived faster. He
> > combines 2 futures like CompletableFuture.anyOf(...). Consequently
> > even if we prohibit CompletableFuture.complete(...) explicitly then it
> > will be possible to create a combination that will allow premature
> > future completion. After all generally CompletableFuture is a
> > placeholder for async computaion result and if a user wants to
> > substitute result returned from Ignite why should we disallow him to
> > do it?
> >
> > Also I found one more suspicious thing with CompletableFuture. As it
> > is a concrete class it implements a cancel() method. And as I see the
> > implementation does not try to cancel underlying computations. Is not
> > it a problem?
> >
> > 2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <
> > [hidden email]>:
> > > Ivan,
> > >
> > > It's not really about the "harm", but more about "what should we do if
> > this
> > > method is called?". Imagine the following code:
> > >
> > > CompletableFuture<String> fut = cache.getAsync(key);
> > > fut.complete("something");
> > >
> > > What should happen in this case?
> > >
> > > The point is that currently a future returned from any of Ignite's
> async
> > > operations is supposed to be completed with a value only by Ignite
> > itself,
> > > not by the user. If we follow the same approach in Ignite 3, returning
> > > CompletableFuture is surely wrong in my view.
> > >
> > > At the same time, if we take a fundamentally different route with the
> > async
> > > APIs, this whole discussion might become irrelevant. For example, can
> you
> > > elaborate on your thinking around the reactive API? Do you have any
> > > specifics in mind?
> > >
> > > -Val
> > >
> > > On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <[hidden email]>
> > wrote:
> > >
> > >> > The methods below shouldn't be accessible for user:
> > >> > complete()
> > >> > completeExceptionaly()
> > >>
> > >> Folks, in case of user-facing API, do you think there is a real harm
> > >> in allowing a user to manually "complete" a future? I suppose a user
> > >> employs some post-processing for future results and potentially wants
> > >> to have control of these results as well. E.g. premature completion in
> > >> case when a result is no longer needed is possible usage.
> > >>
> > >> Also I thinkg it might be a good time to ponder about Future/Promise
> > >> APIs in general. Why such API is our choice? Can we choose e.g.
> > >> Reactive API style instead?
> > >>
> > >> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> > >> [hidden email]>:
> > >> > Andrey,
> > >> >
> > >> > I see. So in a nutshell, you're saying that we want to return a
> future
> > >> that
> > >> > the user's code is not allowed to complete. In this case, I think
> it's
> > >> > clear that CompletableFuture is not what we need. We actually need a
> > >> > NonCompletableFuture :)
> > >> >
> > >> > My vote is for the custom interface.
> > >> >
> > >> > -Val
> > >> >
> > >> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> > >> > <[hidden email]>
> > >> > wrote:
> > >> >
> > >> >> Val,
> > >> >>
> > >> >> The methods below shouldn't be accessible for user:
> > >> >> complete()
> > >> >> completeExceptionaly()
> > >> >>
> > >> >> Returning CompletableFuture we must always make a copy to prevent
> the
> > >> >> original future from being completed by mistake.
> > >> >> I think it will NOT be enough to do that returing the future to the
> > >> >> end-user, but from every critical module to the outside of the
> > module,
> > >> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> > >> >> PartitionReleaseFuture to plugins may be serious.
> > >> >>
> > >> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
> > >> >> implementation
> > >> >> will just wrap CompletableFuture these issues will be resolved in
> > >> natural
> > >> >> way.
> > >> >> In addition we can force toCompletableFuture() method to return a
> > >> >> defensive
> > >> >> copy(), that resolves the last concern.
> > >> >>
> > >> >>
> > >> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
> > >> >> <[hidden email]>
> > >> >> wrote:
> > >> >>
> > >> >> > CompletableFuture seems a better option to me.
> > >> >> >
> > >> >> > --
> > >> >> > Regards,
> > >> >> > Konstantin Orlov
> > >> >> >
> > >> >> >
> > >> >> >
> > >> >> >
> > >> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <[hidden email]
> >
> > >> >> > > wrote:
> > >> >> > >
> > >> >> > > On the one hand, I agree with Alexey.
> > >> >> > > CompletableFuture has complete* methods which should not be
> > >> available
> > >> >> to
> > >> >> > > the user code.
> > >> >> > > This can be solved with a simple interface like we do in Thin
> > >> Client:
> > >> >> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
> > >> >> > >
> > >> >> > >
> > >> >> > > On the other hand:
> > >> >> > > - CompletionStage has toCompletableFuture anyway (rather weird)
> > >> >> > > - Other libraries use CompletableFuture and it seems to be fine
> > >> >> > > - Using CompletableFuture is the simplest approach
> > >> >> > >
> > >> >> > >
> > >> >> > > So I lean towards CompletableFuture too.
> > >> >> > >
> > >> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> > >> >> > [hidden email]>
> > >> >> > > wrote:
> > >> >> > >
> > >> >> > >> I do not like Java's CompletableFuture and prefer our own
> Future
> > >> >> > (revised
> > >> >> > >> IgniteFuture).
> > >> >> > >>
> > >> >> > >> My understanding of the Future (or Promise) pattern in general
> > is
> > >> >> having
> > >> >> > >> two separate APIs:
> > >> >> > >>
> > >> >> > >>   1. Server-side: create, set result, raise error, cancel from
> > >> >> > >> server.
> > >> >> > >>   2. Client-side: get result, handle error, cancel from client
> > >> >> > >>
> > >> >> > >> Java's CompletableFuture looks like both the client-side and
> > >> >> > >> server-side API. The "Completeable" prefix in the name is
> > already
> > >> >> > confusing
> > >> >> > >> for a client since it cannot "complete" an operation, only a
> > >> >> > >> server
> > >> >> can.
> > >> >> > >>
> > >> >> > >> I would create our own IgniteFuture adding client-side
> > >> functionality
> > >> >> we
> > >> >> > >> currently miss (like client-side cancellation).
> > >> >> > >>
> > >> >> > >>
> > >> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> > >> >> > >> [hidden email]>:
> > >> >> > >>
> > >> >> > >>> Andrey,
> > >> >> > >>>
> > >> >> > >>> Can you compile a full list of these risky methods, and
> > >> >> > >>> elaborate
> > >> >> > >>> on
> > >> >> > what
> > >> >> > >>> the risks are?
> > >> >> > >>>
> > >> >> > >>> Generally, CompletableFuture is a much better option, because
> > >> >> > >>> it's
> > >> >> > >>> standard. But we need to make sure it actually fits our needs
> > >> >> > >>> and
> > >> >> > doesn't
> > >> >> > >>> do more harm than good.
> > >> >> > >>>
> > >> >> > >>> -Val
> > >> >> > >>>
> > >> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> > >> >> > >>> [hidden email]> wrote:
> > >> >> > >>>
> > >> >> > >>>> I think both options are fine, but personally lean toward
> > >> >> > >>>> CompletableFuture.
> > >> >> > >>>>
> > >> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]>:
> > >> >> > >>>>
> > >> >> > >>>>> I would suggest using CompletableFuture -- I don't see a
> need
> > >> for
> > >> >> > >>>>> a
> > >> >> > >>>> custom
> > >> >> > >>>>> interface that is unique to us.
> > >> >> > >>>>>
> > >> >> > >>>>> It also allows a lower barrier for new contributors for
> > >> >> understanding
> > >> >> > >>>>> existing code
> > >> >> > >>>>>
> > >> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > >> >> > >>> [hidden email]
> > >> >> > >>>>>
> > >> >> > >>>>> wrote:
> > >> >> > >>>>>
> > >> >> > >>>>>> Hi Igniters,
> > >> >> > >>>>>>
> > >> >> > >>>>>> I'd like to start a discussion about replacing our custom
> > >> >> > >>> IgniteFuture
> > >> >> > >>>>>> class with CompletableFuture - existed JDK class
> > >> >> > >>>>>> or rework it's implementation (like some other products
> > done)
> > >> to
> > >> >> > >>>>>> a
> > >> >> > >>>>>> composition of CompletionStage and Future interfaces.
> > >> >> > >>>>>> or maybe other option if you have any ideas. Do you?
> > >> >> > >>>>>>
> > >> >> > >>>>>> 1. The first approach pros and cons are
> > >> >> > >>>>>> + Well-known JDK class
> > >> >> > >>>>>> + Already implemented
> > >> >> > >>>>>> - It is a class, not an interface.
> > >> >> > >>>>>> - Expose some potentially harmful methods like
> "complete()".
> > >> >> > >>>>>>
> > >> >> > >>>>>> On the other side, it has copy() method to create
> defensive
> > >> copy
> > >> >> > >> and
> > >> >> > >>>>>> minimalCompletionStage() to restrict harmful method usage.
> > >> >> > >>>>>> Thus, this look like an applicable solution, but we should
> > be
> > >> >> > >> careful
> > >> >> > >>>>>> exposing internal future to the outside.
> > >> >> > >>>>>>
> > >> >> > >>>>>> 2. The second approach is to implement our own interface
> > like
> > >> >> > >>>>>> the
> > >> >> > >>> next
> > >> >> > >>>>> one:
> > >> >> > >>>>>>
> > >> >> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>,
> > >> Future<T>
> > >> >> > >>>>>> {
> > >> >> > >>>>>> }
> > >> >> > >>>>>>
> > >> >> > >>>>>> Pros and cons are
> > >> >> > >>>>>> + Our interfaces/classes contracts will expose an
> interface
> > >> >> > >>>>>> rather
> > >> >> > >>> than
> > >> >> > >>>>>> concrete implementation.
> > >> >> > >>>>>> + All methods are safe.
> > >> >> > >>>>>> - Some implementation is required.
> > >> >> > >>>>>> - CompletableStage has a method toCompletableFuture() and
> > can
> > >> be
> > >> >> > >>>>> converted
> > >> >> > >>>>>> to CompletableFuture. This should be supported.
> > >> >> > >>>>>>
> > >> >> > >>>>>> However, we still could wrap CompletableFuture and don't
> > >> >> > >>>>>> bother
> > >> >> > >> about
> > >> >> > >>>>>> creating a defensive copy.
> > >> >> > >>>>>>
> > >> >> > >>>>>>
> > >> >> > >>>>>> Other project experience:
> > >> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> > >> >> > >>>>>> * Redis goes the second approach [2]
> > >> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3]. However,
> > >> >> > >>>>>> they
> > >> >> > >> have
> > >> >> > >>>>> custom
> > >> >> > >>>>>> future classes and a number of helpers that could be
> > replaced
> > >> >> > >>>>>> with
> > >> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> > >> >> > >>>>>>
> > >> >> > >>>>>> Any thoughts?
> > >> >> > >>>>>>
> > >> >> > >>>>>> [1]
> > >> >> > >>>>>>
> > >> >> > >>>>>>
> > >> >> > >>>>>
> > >> >> > >>>>
> > >> >> > >>>
> > >> >> > >>
> > >> >> >
> > >> >>
> > >>
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > >> >> > >>>>>> [2]
> > >> >> > >>>>>>
> > >> >> > >>>>>>
> > >> >> > >>>>>
> > >> >> > >>>>
> > >> >> > >>>
> > >> >> > >>
> > >> >> >
> > >> >>
> > >>
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > >> >> > >>>>>> [3]
> > >> >> > >>>>>>
> > >> >> > >>>>>>
> > >> >> > >>>>>
> > >> >> > >>>>
> > >> >> > >>>
> > >> >> > >>
> > >> >> >
> > >> >>
> > >>
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > >> >> > >>>>>> --
> > >> >> > >>>>>> Best regards,
> > >> >> > >>>>>> Andrey V. Mashenkov
> > >> >> > >>>>>>
> > >> >> > >>>>>
> > >> >> > >>>>
> > >> >> > >>>>
> > >> >> > >>>> --
> > >> >> > >>>>
> > >> >> > >>>> Best regards,
> > >> >> > >>>> Alexei Scherbakov
> > >> >> > >>>>
> > >> >> > >>>
> > >> >> > >>
> > >> >> > >>
> > >> >> > >> --
> > >> >> > >> Best regards,
> > >> >> > >> Alexey
> > >> >> > >>
> > >> >> >
> > >> >> >
> > >> >>
> > >> >> --
> > >> >> Best regards,
> > >> >> Andrey V. Mashenkov
> > >> >>
> > >> >
> > >>
> > >>
> > >> --
> > >>
> > >> Best regards,
> > >> Ivan Pavlukhin
> > >>
> > >
> >
> >
> > --
> >
> > Best regards,
> > Ivan Pavlukhin
> >
>

--
Best regards,
Andrey V. Mashenkov

[Denis Garus]

Hello!

> Let's say a user started a compute with fut = compute.runAsync(task);
> and now calls fut.complete(someVal); Does this mean that Ignite no longer
needs to execute the task?
> If the task is currently running, does it need to be canceled?

Yes, this case looks like Ignite should cancel computations because a user
wants to complete the future. Why not?
If there will be an opportunity to cancel a future, why is it a bad option
to finish a future through a complete() method?

> If you look at Ignite-2 code, you may found a number of places where we
return e.g. exchange futures or partition release futures.
> Assume the impact if we will return CompletableFuture instead, which can
be completed in 3-rd party plugin by mistake?

If exchange futures or partition release futures can be returned to 3-rd
party plugin by mistake, it is poor encapsulation.
And if it will be IgniteFuter rather than CompletedFuture, anyway, this can
harm.

вт, 30 мар. 2021 г. в 13:14, Andrey Mashenkov <[hidden email]>:

> Guys,
>
> I want to remember there is one more point to pay attention to.
> Extending Future and CompletableStage is more than just prevents unexpected
> behavior if a user completed the future.
>
> First of all, it helps us to write safer code as we won't a method contract
> exposed such methods as to a user as to a developer.
> If you look at Ignite-2 code, you may found a number of places where we
> return e.g. exchange futures or partition release futures.
> Assume the impact if we will return CompletableFuture instead, which can be
> completed in 3-rd party plugin by mistake?
>
> The suggested approach allows us to don't bother if a CompletableFuture has
> to be wrapped or not.
>
>
> On Tue, Mar 30, 2021 at 12:22 PM Alexey Goncharuk <
> [hidden email]> wrote:
>
> > Ivan,
> >
> > My concern with the concept of a user completing the future returned from
> > Ignite public API is that it is unclear how to interpret this action
> (this
> > backs Val's message).
> > Let's say a user started a compute with fut = compute.runAsync(task); and
> > now calls fut.complete(someVal); Does this mean that Ignite no longer
> needs
> > to execute the task? If the task is currently running, does it need to be
> > canceled?
> >
> > Using CompletableFuture.anyOf() is a good instrument in this case because
> > it makes the 'first future wins' contract explicit in the code. Besides
> > that, the point regarding the cancel() method is valid, and we will need
> > some custom mechanics to cancel a computation, so a custom interface that
> > simply extends both Future and CompletableStage seems reasonable to me.
> >
> > --AG
> >
> > пн, 29 мар. 2021 г. в 09:12, Ivan Pavlukhin <[hidden email]>:
> >
> > > Val,
> > >
> > > There were enough hype around Reactive programming past years. I
> > > remind a lot of talks about RxJava. And I suppose it worth to consider
> > > it. But it requires some time to study modern trends to make a choice.
> > > So far I am not ready to facilitate Reactive API for Ignite 3.
> > >
> > > Regarding CompletableFuture.
> > >
> > > > The point is that currently a future returned from any of Ignite's
> > async
> > > > operations is supposed to be completed with a value only by Ignite
> > > itself,
> > > > not by the user. If we follow the same approach in Ignite 3,
> returning
> > > > CompletableFuture is surely wrong in my view.
> > >
> > > My first thoughts was similar. But later I thought what a user would
> > > like do with returned future. And one of cases I imagined was a case
> > > of alternative result. E.g. a user uses Ignite and another data source
> > > in his application. He wants to use a value arrived faster. He
> > > combines 2 futures like CompletableFuture.anyOf(...). Consequently
> > > even if we prohibit CompletableFuture.complete(...) explicitly then it
> > > will be possible to create a combination that will allow premature
> > > future completion. After all generally CompletableFuture is a
> > > placeholder for async computaion result and if a user wants to
> > > substitute result returned from Ignite why should we disallow him to
> > > do it?
> > >
> > > Also I found one more suspicious thing with CompletableFuture. As it
> > > is a concrete class it implements a cancel() method. And as I see the
> > > implementation does not try to cancel underlying computations. Is not
> > > it a problem?
> > >
> > > 2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <
> > > [hidden email]>:
> > > > Ivan,
> > > >
> > > > It's not really about the "harm", but more about "what should we do
> if
> > > this
> > > > method is called?". Imagine the following code:
> > > >
> > > > CompletableFuture<String> fut = cache.getAsync(key);
> > > > fut.complete("something");
> > > >
> > > > What should happen in this case?
> > > >
> > > > The point is that currently a future returned from any of Ignite's
> > async
> > > > operations is supposed to be completed with a value only by Ignite
> > > itself,
> > > > not by the user. If we follow the same approach in Ignite 3,
> returning
> > > > CompletableFuture is surely wrong in my view.
> > > >
> > > > At the same time, if we take a fundamentally different route with the
> > > async
> > > > APIs, this whole discussion might become irrelevant. For example, can
> > you
> > > > elaborate on your thinking around the reactive API? Do you have any
> > > > specifics in mind?
> > > >
> > > > -Val
> > > >
> > > > On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <[hidden email]>
> > > wrote:
> > > >
> > > >> > The methods below shouldn't be accessible for user:
> > > >> > complete()
> > > >> > completeExceptionaly()
> > > >>
> > > >> Folks, in case of user-facing API, do you think there is a real harm
> > > >> in allowing a user to manually "complete" a future? I suppose a user
> > > >> employs some post-processing for future results and potentially
> wants
> > > >> to have control of these results as well. E.g. premature completion
> in
> > > >> case when a result is no longer needed is possible usage.
> > > >>
> > > >> Also I thinkg it might be a good time to ponder about Future/Promise
> > > >> APIs in general. Why such API is our choice? Can we choose e.g.
> > > >> Reactive API style instead?
> > > >>
> > > >> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> > > >> [hidden email]>:
> > > >> > Andrey,
> > > >> >
> > > >> > I see. So in a nutshell, you're saying that we want to return a
> > future
> > > >> that
> > > >> > the user's code is not allowed to complete. In this case, I think
> > it's
> > > >> > clear that CompletableFuture is not what we need. We actually
> need a
> > > >> > NonCompletableFuture :)
> > > >> >
> > > >> > My vote is for the custom interface.
> > > >> >
> > > >> > -Val
> > > >> >
> > > >> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> > > >> > <[hidden email]>
> > > >> > wrote:
> > > >> >
> > > >> >> Val,
> > > >> >>
> > > >> >> The methods below shouldn't be accessible for user:
> > > >> >> complete()
> > > >> >> completeExceptionaly()
> > > >> >>
> > > >> >> Returning CompletableFuture we must always make a copy to prevent
> > the
> > > >> >> original future from being completed by mistake.
> > > >> >> I think it will NOT be enough to do that returing the future to
> the
> > > >> >> end-user, but from every critical module to the outside of the
> > > module,
> > > >> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> > > >> >> PartitionReleaseFuture to plugins may be serious.
> > > >> >>
> > > >> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
> > > >> >> implementation
> > > >> >> will just wrap CompletableFuture these issues will be resolved in
> > > >> natural
> > > >> >> way.
> > > >> >> In addition we can force toCompletableFuture() method to return a
> > > >> >> defensive
> > > >> >> copy(), that resolves the last concern.
> > > >> >>
> > > >> >>
> > > >> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
> > > >> >> <[hidden email]>
> > > >> >> wrote:
> > > >> >>
> > > >> >> > CompletableFuture seems a better option to me.
> > > >> >> >
> > > >> >> > --
> > > >> >> > Regards,
> > > >> >> > Konstantin Orlov
> > > >> >> >
> > > >> >> >
> > > >> >> >
> > > >> >> >
> > > >> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <
> [hidden email]
> > >
> > > >> >> > > wrote:
> > > >> >> > >
> > > >> >> > > On the one hand, I agree with Alexey.
> > > >> >> > > CompletableFuture has complete* methods which should not be
> > > >> available
> > > >> >> to
> > > >> >> > > the user code.
> > > >> >> > > This can be solved with a simple interface like we do in Thin
> > > >> Client:
> > > >> >> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
> > > >> >> > >
> > > >> >> > >
> > > >> >> > > On the other hand:
> > > >> >> > > - CompletionStage has toCompletableFuture anyway (rather
> weird)
> > > >> >> > > - Other libraries use CompletableFuture and it seems to be
> fine
> > > >> >> > > - Using CompletableFuture is the simplest approach
> > > >> >> > >
> > > >> >> > >
> > > >> >> > > So I lean towards CompletableFuture too.
> > > >> >> > >
> > > >> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> > > >> >> > [hidden email]>
> > > >> >> > > wrote:
> > > >> >> > >
> > > >> >> > >> I do not like Java's CompletableFuture and prefer our own
> > Future
> > > >> >> > (revised
> > > >> >> > >> IgniteFuture).
> > > >> >> > >>
> > > >> >> > >> My understanding of the Future (or Promise) pattern in
> general
> > > is
> > > >> >> having
> > > >> >> > >> two separate APIs:
> > > >> >> > >>
> > > >> >> > >>   1. Server-side: create, set result, raise error, cancel
> from
> > > >> >> > >> server.
> > > >> >> > >>   2. Client-side: get result, handle error, cancel from
> client
> > > >> >> > >>
> > > >> >> > >> Java's CompletableFuture looks like both the client-side and
> > > >> >> > >> server-side API. The "Completeable" prefix in the name is
> > > already
> > > >> >> > confusing
> > > >> >> > >> for a client since it cannot "complete" an operation, only a
> > > >> >> > >> server
> > > >> >> can.
> > > >> >> > >>
> > > >> >> > >> I would create our own IgniteFuture adding client-side
> > > >> functionality
> > > >> >> we
> > > >> >> > >> currently miss (like client-side cancellation).
> > > >> >> > >>
> > > >> >> > >>
> > > >> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> > > >> >> > >> [hidden email]>:
> > > >> >> > >>
> > > >> >> > >>> Andrey,
> > > >> >> > >>>
> > > >> >> > >>> Can you compile a full list of these risky methods, and
> > > >> >> > >>> elaborate
> > > >> >> > >>> on
> > > >> >> > what
> > > >> >> > >>> the risks are?
> > > >> >> > >>>
> > > >> >> > >>> Generally, CompletableFuture is a much better option,
> because
> > > >> >> > >>> it's
> > > >> >> > >>> standard. But we need to make sure it actually fits our
> needs
> > > >> >> > >>> and
> > > >> >> > doesn't
> > > >> >> > >>> do more harm than good.
> > > >> >> > >>>
> > > >> >> > >>> -Val
> > > >> >> > >>>
> > > >> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> > > >> >> > >>> [hidden email]> wrote:
> > > >> >> > >>>
> > > >> >> > >>>> I think both options are fine, but personally lean toward
> > > >> >> > >>>> CompletableFuture.
> > > >> >> > >>>>
> > > >> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <[hidden email]
> >:
> > > >> >> > >>>>
> > > >> >> > >>>>> I would suggest using CompletableFuture -- I don't see a
> > need
> > > >> for
> > > >> >> > >>>>> a
> > > >> >> > >>>> custom
> > > >> >> > >>>>> interface that is unique to us.
> > > >> >> > >>>>>
> > > >> >> > >>>>> It also allows a lower barrier for new contributors for
> > > >> >> understanding
> > > >> >> > >>>>> existing code
> > > >> >> > >>>>>
> > > >> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > > >> >> > >>> [hidden email]
> > > >> >> > >>>>>
> > > >> >> > >>>>> wrote:
> > > >> >> > >>>>>
> > > >> >> > >>>>>> Hi Igniters,
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> I'd like to start a discussion about replacing our
> custom
> > > >> >> > >>> IgniteFuture
> > > >> >> > >>>>>> class with CompletableFuture - existed JDK class
> > > >> >> > >>>>>> or rework it's implementation (like some other products
> > > done)
> > > >> to
> > > >> >> > >>>>>> a
> > > >> >> > >>>>>> composition of CompletionStage and Future interfaces.
> > > >> >> > >>>>>> or maybe other option if you have any ideas. Do you?
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> 1. The first approach pros and cons are
> > > >> >> > >>>>>> + Well-known JDK class
> > > >> >> > >>>>>> + Already implemented
> > > >> >> > >>>>>> - It is a class, not an interface.
> > > >> >> > >>>>>> - Expose some potentially harmful methods like
> > "complete()".
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> On the other side, it has copy() method to create
> > defensive
> > > >> copy
> > > >> >> > >> and
> > > >> >> > >>>>>> minimalCompletionStage() to restrict harmful method
> usage.
> > > >> >> > >>>>>> Thus, this look like an applicable solution, but we
> should
> > > be
> > > >> >> > >> careful
> > > >> >> > >>>>>> exposing internal future to the outside.
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> 2. The second approach is to implement our own interface
> > > like
> > > >> >> > >>>>>> the
> > > >> >> > >>> next
> > > >> >> > >>>>> one:
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>,
> > > >> Future<T>
> > > >> >> > >>>>>> {
> > > >> >> > >>>>>> }
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> Pros and cons are
> > > >> >> > >>>>>> + Our interfaces/classes contracts will expose an
> > interface
> > > >> >> > >>>>>> rather
> > > >> >> > >>> than
> > > >> >> > >>>>>> concrete implementation.
> > > >> >> > >>>>>> + All methods are safe.
> > > >> >> > >>>>>> - Some implementation is required.
> > > >> >> > >>>>>> - CompletableStage has a method toCompletableFuture()
> and
> > > can
> > > >> be
> > > >> >> > >>>>> converted
> > > >> >> > >>>>>> to CompletableFuture. This should be supported.
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> However, we still could wrap CompletableFuture and don't
> > > >> >> > >>>>>> bother
> > > >> >> > >> about
> > > >> >> > >>>>>> creating a defensive copy.
> > > >> >> > >>>>>>
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> Other project experience:
> > > >> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> > > >> >> > >>>>>> * Redis goes the second approach [2]
> > > >> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3].
> However,
> > > >> >> > >>>>>> they
> > > >> >> > >> have
> > > >> >> > >>>>> custom
> > > >> >> > >>>>>> future classes and a number of helpers that could be
> > > replaced
> > > >> >> > >>>>>> with
> > > >> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> Any thoughts?
> > > >> >> > >>>>>>
> > > >> >> > >>>>>> [1]
> > > >> >> > >>>>>>
> > > >> >> > >>>>>>
> > > >> >> > >>>>>
> > > >> >> > >>>>
> > > >> >> > >>>
> > > >> >> > >>
> > > >> >> >
> > > >> >>
> > > >>
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > >> >> > >>>>>> [2]
> > > >> >> > >>>>>>
> > > >> >> > >>>>>>
> > > >> >> > >>>>>
> > > >> >> > >>>>
> > > >> >> > >>>
> > > >> >> > >>
> > > >> >> >
> > > >> >>
> > > >>
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > >> >> > >>>>>> [3]
> > > >> >> > >>>>>>
> > > >> >> > >>>>>>
> > > >> >> > >>>>>
> > > >> >> > >>>>
> > > >> >> > >>>
> > > >> >> > >>
> > > >> >> >
> > > >> >>
> > > >>
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > >> >> > >>>>>> --
> > > >> >> > >>>>>> Best regards,
> > > >> >> > >>>>>> Andrey V. Mashenkov
> > > >> >> > >>>>>>
> > > >> >> > >>>>>
> > > >> >> > >>>>
> > > >> >> > >>>>
> > > >> >> > >>>> --
> > > >> >> > >>>>
> > > >> >> > >>>> Best regards,
> > > >> >> > >>>> Alexei Scherbakov
> > > >> >> > >>>>
> > > >> >> > >>>
> > > >> >> > >>
> > > >> >> > >>
> > > >> >> > >> --
> > > >> >> > >> Best regards,
> > > >> >> > >> Alexey
> > > >> >> > >>
> > > >> >> >
> > > >> >> >
> > > >> >>
> > > >> >> --
> > > >> >> Best regards,
> > > >> >> Andrey V. Mashenkov
> > > >> >>
> > > >> >
> > > >>
> > > >>
> > > >> --
> > > >>
> > > >> Best regards,
> > > >> Ivan Pavlukhin
> > > >>
> > > >
> > >
> > >
> > > --
> > >
> > > Best regards,
> > > Ivan Pavlukhin
> > >
> >
>
>
> --
> Best regards,
> Andrey V. Mashenkov
>

[Andrew Mashenkov]

>
> Yes, this case looks like Ignite should cancel computations because a user
> wants to complete the future. Why not?
> If there will be an opportunity to cancel a future, why is it a bad option
> to finish a future through a complete() method?

Future has cancel() method for this.
Completing future from outside will never respect other subscribers that
may expect other guatantees.

>
> If exchange futures or partition release futures can be returned to 3-rd
> party plugin by mistake, it is poor encapsulation.
> And if it will be IgniteFuter rather than CompletedFuture, anyway, this can
> harm.
>
IgniteFuture contract will not have complete() or similar methods, but we a
free to pass any implementation.
Obviously, if a user casts the future to CompletableFuture or uses a
reflection to access IgniteFutureImpl hidden methods -
that means the user breaks the contract and CompletableFuture defensive
copy will not help either.


On Tue, Mar 30, 2021 at 2:28 PM Denis Garus <[hidden email]> wrote:

> Hello!
>
> > Let's say a user started a compute with fut = compute.runAsync(task);
> > and now calls fut.complete(someVal); Does this mean that Ignite no longer
> needs to execute the task?
> > If the task is currently running, does it need to be canceled?
>
> Yes, this case looks like Ignite should cancel computations because a user
> wants to complete the future. Why not?
> If there will be an opportunity to cancel a future, why is it a bad option
> to finish a future through a complete() method?
>
> > If you look at Ignite-2 code, you may found a number of places where we
> return e.g. exchange futures or partition release futures.
> > Assume the impact if we will return CompletableFuture instead, which can
> be completed in 3-rd party plugin by mistake?
>
> If exchange futures or partition release futures can be returned to 3-rd
> party plugin by mistake, it is poor encapsulation.
> And if it will be IgniteFuter rather than CompletedFuture, anyway, this can
> harm.
>
> вт, 30 мар. 2021 г. в 13:14, Andrey Mashenkov <[hidden email]
> >:
>
> > Guys,
> >
> > I want to remember there is one more point to pay attention to.
> > Extending Future and CompletableStage is more than just prevents
> unexpected
> > behavior if a user completed the future.
> >
> > First of all, it helps us to write safer code as we won't a method
> contract
> > exposed such methods as to a user as to a developer.
> > If you look at Ignite-2 code, you may found a number of places where we
> > return e.g. exchange futures or partition release futures.
> > Assume the impact if we will return CompletableFuture instead, which can
> be
> > completed in 3-rd party plugin by mistake?
> >
> > The suggested approach allows us to don't bother if a CompletableFuture
> has
> > to be wrapped or not.
> >
> >
> > On Tue, Mar 30, 2021 at 12:22 PM Alexey Goncharuk <
> > [hidden email]> wrote:
> >
> > > Ivan,
> > >
> > > My concern with the concept of a user completing the future returned
> from
> > > Ignite public API is that it is unclear how to interpret this action
> > (this
> > > backs Val's message).
> > > Let's say a user started a compute with fut = compute.runAsync(task);
> and
> > > now calls fut.complete(someVal); Does this mean that Ignite no longer
> > needs
> > > to execute the task? If the task is currently running, does it need to
> be
> > > canceled?
> > >
> > > Using CompletableFuture.anyOf() is a good instrument in this case
> because
> > > it makes the 'first future wins' contract explicit in the code. Besides
> > > that, the point regarding the cancel() method is valid, and we will
> need
> > > some custom mechanics to cancel a computation, so a custom interface
> that
> > > simply extends both Future and CompletableStage seems reasonable to me.
> > >
> > > --AG
> > >
> > > пн, 29 мар. 2021 г. в 09:12, Ivan Pavlukhin <[hidden email]>:
> > >
> > > > Val,
> > > >
> > > > There were enough hype around Reactive programming past years. I
> > > > remind a lot of talks about RxJava. And I suppose it worth to
> consider
> > > > it. But it requires some time to study modern trends to make a
> choice.
> > > > So far I am not ready to facilitate Reactive API for Ignite 3.
> > > >
> > > > Regarding CompletableFuture.
> > > >
> > > > > The point is that currently a future returned from any of Ignite's
> > > async
> > > > > operations is supposed to be completed with a value only by Ignite
> > > > itself,
> > > > > not by the user. If we follow the same approach in Ignite 3,
> > returning
> > > > > CompletableFuture is surely wrong in my view.
> > > >
> > > > My first thoughts was similar. But later I thought what a user would
> > > > like do with returned future. And one of cases I imagined was a case
> > > > of alternative result. E.g. a user uses Ignite and another data
> source
> > > > in his application. He wants to use a value arrived faster. He
> > > > combines 2 futures like CompletableFuture.anyOf(...). Consequently
> > > > even if we prohibit CompletableFuture.complete(...) explicitly then
> it
> > > > will be possible to create a combination that will allow premature
> > > > future completion. After all generally CompletableFuture is a
> > > > placeholder for async computaion result and if a user wants to
> > > > substitute result returned from Ignite why should we disallow him to
> > > > do it?
> > > >
> > > > Also I found one more suspicious thing with CompletableFuture. As it
> > > > is a concrete class it implements a cancel() method. And as I see the
> > > > implementation does not try to cancel underlying computations. Is not
> > > > it a problem?
> > > >
> > > > 2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <
> > > > [hidden email]>:
> > > > > Ivan,
> > > > >
> > > > > It's not really about the "harm", but more about "what should we do
> > if
> > > > this
> > > > > method is called?". Imagine the following code:
> > > > >
> > > > > CompletableFuture<String> fut = cache.getAsync(key);
> > > > > fut.complete("something");
> > > > >
> > > > > What should happen in this case?
> > > > >
> > > > > The point is that currently a future returned from any of Ignite's
> > > async
> > > > > operations is supposed to be completed with a value only by Ignite
> > > > itself,
> > > > > not by the user. If we follow the same approach in Ignite 3,
> > returning
> > > > > CompletableFuture is surely wrong in my view.
> > > > >
> > > > > At the same time, if we take a fundamentally different route with
> the
> > > > async
> > > > > APIs, this whole discussion might become irrelevant. For example,
> can
> > > you
> > > > > elaborate on your thinking around the reactive API? Do you have any
> > > > > specifics in mind?
> > > > >
> > > > > -Val
> > > > >
> > > > > On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <
> [hidden email]>
> > > > wrote:
> > > > >
> > > > >> > The methods below shouldn't be accessible for user:
> > > > >> > complete()
> > > > >> > completeExceptionaly()
> > > > >>
> > > > >> Folks, in case of user-facing API, do you think there is a real
> harm
> > > > >> in allowing a user to manually "complete" a future? I suppose a
> user
> > > > >> employs some post-processing for future results and potentially
> > wants
> > > > >> to have control of these results as well. E.g. premature
> completion
> > in
> > > > >> case when a result is no longer needed is possible usage.
> > > > >>
> > > > >> Also I thinkg it might be a good time to ponder about
> Future/Promise
> > > > >> APIs in general. Why such API is our choice? Can we choose e.g.
> > > > >> Reactive API style instead?
> > > > >>
> > > > >> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> > > > >> [hidden email]>:
> > > > >> > Andrey,
> > > > >> >
> > > > >> > I see. So in a nutshell, you're saying that we want to return a
> > > future
> > > > >> that
> > > > >> > the user's code is not allowed to complete. In this case, I
> think
> > > it's
> > > > >> > clear that CompletableFuture is not what we need. We actually
> > need a
> > > > >> > NonCompletableFuture :)
> > > > >> >
> > > > >> > My vote is for the custom interface.
> > > > >> >
> > > > >> > -Val
> > > > >> >
> > > > >> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> > > > >> > <[hidden email]>
> > > > >> > wrote:
> > > > >> >
> > > > >> >> Val,
> > > > >> >>
> > > > >> >> The methods below shouldn't be accessible for user:
> > > > >> >> complete()
> > > > >> >> completeExceptionaly()
> > > > >> >>
> > > > >> >> Returning CompletableFuture we must always make a copy to
> prevent
> > > the
> > > > >> >> original future from being completed by mistake.
> > > > >> >> I think it will NOT be enough to do that returing the future to
> > the
> > > > >> >> end-user, but from every critical module to the outside of the
> > > > module,
> > > > >> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> > > > >> >> PartitionReleaseFuture to plugins may be serious.
> > > > >> >>
> > > > >> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
> > > > >> >> implementation
> > > > >> >> will just wrap CompletableFuture these issues will be resolved
> in
> > > > >> natural
> > > > >> >> way.
> > > > >> >> In addition we can force toCompletableFuture() method to
> return a
> > > > >> >> defensive
> > > > >> >> copy(), that resolves the last concern.
> > > > >> >>
> > > > >> >>
> > > > >> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
> > > > >> >> <[hidden email]>
> > > > >> >> wrote:
> > > > >> >>
> > > > >> >> > CompletableFuture seems a better option to me.
> > > > >> >> >
> > > > >> >> > --
> > > > >> >> > Regards,
> > > > >> >> > Konstantin Orlov
> > > > >> >> >
> > > > >> >> >
> > > > >> >> >
> > > > >> >> >
> > > > >> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <
> > [hidden email]
> > > >
> > > > >> >> > > wrote:
> > > > >> >> > >
> > > > >> >> > > On the one hand, I agree with Alexey.
> > > > >> >> > > CompletableFuture has complete* methods which should not be
> > > > >> available
> > > > >> >> to
> > > > >> >> > > the user code.
> > > > >> >> > > This can be solved with a simple interface like we do in
> Thin
> > > > >> Client:
> > > > >> >> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
> > > > >> >> > >
> > > > >> >> > >
> > > > >> >> > > On the other hand:
> > > > >> >> > > - CompletionStage has toCompletableFuture anyway (rather
> > weird)
> > > > >> >> > > - Other libraries use CompletableFuture and it seems to be
> > fine
> > > > >> >> > > - Using CompletableFuture is the simplest approach
> > > > >> >> > >
> > > > >> >> > >
> > > > >> >> > > So I lean towards CompletableFuture too.
> > > > >> >> > >
> > > > >> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> > > > >> >> > [hidden email]>
> > > > >> >> > > wrote:
> > > > >> >> > >
> > > > >> >> > >> I do not like Java's CompletableFuture and prefer our own
> > > Future
> > > > >> >> > (revised
> > > > >> >> > >> IgniteFuture).
> > > > >> >> > >>
> > > > >> >> > >> My understanding of the Future (or Promise) pattern in
> > general
> > > > is
> > > > >> >> having
> > > > >> >> > >> two separate APIs:
> > > > >> >> > >>
> > > > >> >> > >>   1. Server-side: create, set result, raise error, cancel
> > from
> > > > >> >> > >> server.
> > > > >> >> > >>   2. Client-side: get result, handle error, cancel from
> > client
> > > > >> >> > >>
> > > > >> >> > >> Java's CompletableFuture looks like both the client-side
> and
> > > > >> >> > >> server-side API. The "Completeable" prefix in the name is
> > > > already
> > > > >> >> > confusing
> > > > >> >> > >> for a client since it cannot "complete" an operation,
> only a
> > > > >> >> > >> server
> > > > >> >> can.
> > > > >> >> > >>
> > > > >> >> > >> I would create our own IgniteFuture adding client-side
> > > > >> functionality
> > > > >> >> we
> > > > >> >> > >> currently miss (like client-side cancellation).
> > > > >> >> > >>
> > > > >> >> > >>
> > > > >> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> > > > >> >> > >> [hidden email]>:
> > > > >> >> > >>
> > > > >> >> > >>> Andrey,
> > > > >> >> > >>>
> > > > >> >> > >>> Can you compile a full list of these risky methods, and
> > > > >> >> > >>> elaborate
> > > > >> >> > >>> on
> > > > >> >> > what
> > > > >> >> > >>> the risks are?
> > > > >> >> > >>>
> > > > >> >> > >>> Generally, CompletableFuture is a much better option,
> > because
> > > > >> >> > >>> it's
> > > > >> >> > >>> standard. But we need to make sure it actually fits our
> > needs
> > > > >> >> > >>> and
> > > > >> >> > doesn't
> > > > >> >> > >>> do more harm than good.
> > > > >> >> > >>>
> > > > >> >> > >>> -Val
> > > > >> >> > >>>
> > > > >> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> > > > >> >> > >>> [hidden email]> wrote:
> > > > >> >> > >>>
> > > > >> >> > >>>> I think both options are fine, but personally lean
> toward
> > > > >> >> > >>>> CompletableFuture.
> > > > >> >> > >>>>
> > > > >> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <
> [hidden email]
> > >:
> > > > >> >> > >>>>
> > > > >> >> > >>>>> I would suggest using CompletableFuture -- I don't see
> a
> > > need
> > > > >> for
> > > > >> >> > >>>>> a
> > > > >> >> > >>>> custom
> > > > >> >> > >>>>> interface that is unique to us.
> > > > >> >> > >>>>>
> > > > >> >> > >>>>> It also allows a lower barrier for new contributors for
> > > > >> >> understanding
> > > > >> >> > >>>>> existing code
> > > > >> >> > >>>>>
> > > > >> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > > > >> >> > >>> [hidden email]
> > > > >> >> > >>>>>
> > > > >> >> > >>>>> wrote:
> > > > >> >> > >>>>>
> > > > >> >> > >>>>>> Hi Igniters,
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> I'd like to start a discussion about replacing our
> > custom
> > > > >> >> > >>> IgniteFuture
> > > > >> >> > >>>>>> class with CompletableFuture - existed JDK class
> > > > >> >> > >>>>>> or rework it's implementation (like some other
> products
> > > > done)
> > > > >> to
> > > > >> >> > >>>>>> a
> > > > >> >> > >>>>>> composition of CompletionStage and Future interfaces.
> > > > >> >> > >>>>>> or maybe other option if you have any ideas. Do you?
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> 1. The first approach pros and cons are
> > > > >> >> > >>>>>> + Well-known JDK class
> > > > >> >> > >>>>>> + Already implemented
> > > > >> >> > >>>>>> - It is a class, not an interface.
> > > > >> >> > >>>>>> - Expose some potentially harmful methods like
> > > "complete()".
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> On the other side, it has copy() method to create
> > > defensive
> > > > >> copy
> > > > >> >> > >> and
> > > > >> >> > >>>>>> minimalCompletionStage() to restrict harmful method
> > usage.
> > > > >> >> > >>>>>> Thus, this look like an applicable solution, but we
> > should
> > > > be
> > > > >> >> > >> careful
> > > > >> >> > >>>>>> exposing internal future to the outside.
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> 2. The second approach is to implement our own
> interface
> > > > like
> > > > >> >> > >>>>>> the
> > > > >> >> > >>> next
> > > > >> >> > >>>>> one:
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>,
> > > > >> Future<T>
> > > > >> >> > >>>>>> {
> > > > >> >> > >>>>>> }
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> Pros and cons are
> > > > >> >> > >>>>>> + Our interfaces/classes contracts will expose an
> > > interface
> > > > >> >> > >>>>>> rather
> > > > >> >> > >>> than
> > > > >> >> > >>>>>> concrete implementation.
> > > > >> >> > >>>>>> + All methods are safe.
> > > > >> >> > >>>>>> - Some implementation is required.
> > > > >> >> > >>>>>> - CompletableStage has a method toCompletableFuture()
> > and
> > > > can
> > > > >> be
> > > > >> >> > >>>>> converted
> > > > >> >> > >>>>>> to CompletableFuture. This should be supported.
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> However, we still could wrap CompletableFuture and
> don't
> > > > >> >> > >>>>>> bother
> > > > >> >> > >> about
> > > > >> >> > >>>>>> creating a defensive copy.
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> Other project experience:
> > > > >> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> > > > >> >> > >>>>>> * Redis goes the second approach [2]
> > > > >> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3].
> > However,
> > > > >> >> > >>>>>> they
> > > > >> >> > >> have
> > > > >> >> > >>>>> custom
> > > > >> >> > >>>>>> future classes and a number of helpers that could be
> > > > replaced
> > > > >> >> > >>>>>> with
> > > > >> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> Any thoughts?
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> [1]
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>
> > > > >> >> > >>
> > > > >> >> >
> > > > >> >>
> > > > >>
> > > >
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > > >> >> > >>>>>> [2]
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>
> > > > >> >> > >>
> > > > >> >> >
> > > > >> >>
> > > > >>
> > > >
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > > >> >> > >>>>>> [3]
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>
> > > > >> >> > >>
> > > > >> >> >
> > > > >> >>
> > > > >>
> > > >
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > > >> >> > >>>>>> --
> > > > >> >> > >>>>>> Best regards,
> > > > >> >> > >>>>>> Andrey V. Mashenkov
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>> --
> > > > >> >> > >>>>
> > > > >> >> > >>>> Best regards,
> > > > >> >> > >>>> Alexei Scherbakov
> > > > >> >> > >>>>
> > > > >> >> > >>>
> > > > >> >> > >>
> > > > >> >> > >>
> > > > >> >> > >> --
> > > > >> >> > >> Best regards,
> > > > >> >> > >> Alexey
> > > > >> >> > >>
> > > > >> >> >
> > > > >> >> >
> > > > >> >>
> > > > >> >> --
> > > > >> >> Best regards,
> > > > >> >> Andrey V. Mashenkov
> > > > >> >>
> > > > >> >
> > > > >>
> > > > >>
> > > > >> --
> > > > >>
> > > > >> Best regards,
> > > > >> Ivan Pavlukhin
> > > > >>
> > > > >
> > > >
> > > >
> > > > --
> > > >
> > > > Best regards,
> > > > Ivan Pavlukhin
> > > >
> > >
> >
> >
> > --
> > Best regards,
> > Andrey V. Mashenkov
> >
>

--
Best regards,
Andrey V. Mashenkov

[Atri Sharma-2]

IMO the only way Ignite should cancel computations is iff cancel method is
invoked, not implicitly if complete is invoked.

On Tue, 30 Mar 2021 at 4:58 PM, Denis Garus <[hidden email]> wrote:

> Hello!
>
> > Let's say a user started a compute with fut = compute.runAsync(task);
> > and now calls fut.complete(someVal); Does this mean that Ignite no longer
> needs to execute the task?
> > If the task is currently running, does it need to be canceled?
>
> Yes, this case looks like Ignite should cancel computations because a user
> wants to complete the future. Why not?
> If there will be an opportunity to cancel a future, why is it a bad option
> to finish a future through a complete() method?
>
> > If you look at Ignite-2 code, you may found a number of places where we
> return e.g. exchange futures or partition release futures.
> > Assume the impact if we will return CompletableFuture instead, which can
> be completed in 3-rd party plugin by mistake?
>
> If exchange futures or partition release futures can be returned to 3-rd
> party plugin by mistake, it is poor encapsulation.
> And if it will be IgniteFuter rather than CompletedFuture, anyway, this can
> harm.
>
> вт, 30 мар. 2021 г. в 13:14, Andrey Mashenkov <[hidden email]
> >:
>
> > Guys,
> >
> > I want to remember there is one more point to pay attention to.
> > Extending Future and CompletableStage is more than just prevents
> unexpected
> > behavior if a user completed the future.
> >
> > First of all, it helps us to write safer code as we won't a method
> contract
> > exposed such methods as to a user as to a developer.
> > If you look at Ignite-2 code, you may found a number of places where we
> > return e.g. exchange futures or partition release futures.
> > Assume the impact if we will return CompletableFuture instead, which can
> be
> > completed in 3-rd party plugin by mistake?
> >
> > The suggested approach allows us to don't bother if a CompletableFuture
> has
> > to be wrapped or not.
> >
> >
> > On Tue, Mar 30, 2021 at 12:22 PM Alexey Goncharuk <
> > [hidden email]> wrote:
> >
> > > Ivan,
> > >
> > > My concern with the concept of a user completing the future returned
> from
> > > Ignite public API is that it is unclear how to interpret this action
> > (this
> > > backs Val's message).
> > > Let's say a user started a compute with fut = compute.runAsync(task);
> and
> > > now calls fut.complete(someVal); Does this mean that Ignite no longer
> > needs
> > > to execute the task? If the task is currently running, does it need to
> be
> > > canceled?
> > >
> > > Using CompletableFuture.anyOf() is a good instrument in this case
> because
> > > it makes the 'first future wins' contract explicit in the code. Besides
> > > that, the point regarding the cancel() method is valid, and we will
> need
> > > some custom mechanics to cancel a computation, so a custom interface
> that
> > > simply extends both Future and CompletableStage seems reasonable to me.
> > >
> > > --AG
> > >
> > > пн, 29 мар. 2021 г. в 09:12, Ivan Pavlukhin <[hidden email]>:
> > >
> > > > Val,
> > > >
> > > > There were enough hype around Reactive programming past years. I
> > > > remind a lot of talks about RxJava. And I suppose it worth to
> consider
> > > > it. But it requires some time to study modern trends to make a
> choice.
> > > > So far I am not ready to facilitate Reactive API for Ignite 3.
> > > >
> > > > Regarding CompletableFuture.
> > > >
> > > > > The point is that currently a future returned from any of Ignite's
> > > async
> > > > > operations is supposed to be completed with a value only by Ignite
> > > > itself,
> > > > > not by the user. If we follow the same approach in Ignite 3,
> > returning
> > > > > CompletableFuture is surely wrong in my view.
> > > >
> > > > My first thoughts was similar. But later I thought what a user would
> > > > like do with returned future. And one of cases I imagined was a case
> > > > of alternative result. E.g. a user uses Ignite and another data
> source
> > > > in his application. He wants to use a value arrived faster. He
> > > > combines 2 futures like CompletableFuture.anyOf(...). Consequently
> > > > even if we prohibit CompletableFuture.complete(...) explicitly then
> it
> > > > will be possible to create a combination that will allow premature
> > > > future completion. After all generally CompletableFuture is a
> > > > placeholder for async computaion result and if a user wants to
> > > > substitute result returned from Ignite why should we disallow him to
> > > > do it?
> > > >
> > > > Also I found one more suspicious thing with CompletableFuture. As it
> > > > is a concrete class it implements a cancel() method. And as I see the
> > > > implementation does not try to cancel underlying computations. Is not
> > > > it a problem?
> > > >
> > > > 2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <
> > > > [hidden email]>:
> > > > > Ivan,
> > > > >
> > > > > It's not really about the "harm", but more about "what should we do
> > if
> > > > this
> > > > > method is called?". Imagine the following code:
> > > > >
> > > > > CompletableFuture<String> fut = cache.getAsync(key);
> > > > > fut.complete("something");
> > > > >
> > > > > What should happen in this case?
> > > > >
> > > > > The point is that currently a future returned from any of Ignite's
> > > async
> > > > > operations is supposed to be completed with a value only by Ignite
> > > > itself,
> > > > > not by the user. If we follow the same approach in Ignite 3,
> > returning
> > > > > CompletableFuture is surely wrong in my view.
> > > > >
> > > > > At the same time, if we take a fundamentally different route with
> the
> > > > async
> > > > > APIs, this whole discussion might become irrelevant. For example,
> can
> > > you
> > > > > elaborate on your thinking around the reactive API? Do you have any
> > > > > specifics in mind?
> > > > >
> > > > > -Val
> > > > >
> > > > > On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <
> [hidden email]>
> > > > wrote:
> > > > >
> > > > >> > The methods below shouldn't be accessible for user:
> > > > >> > complete()
> > > > >> > completeExceptionaly()
> > > > >>
> > > > >> Folks, in case of user-facing API, do you think there is a real
> harm
> > > > >> in allowing a user to manually "complete" a future? I suppose a
> user
> > > > >> employs some post-processing for future results and potentially
> > wants
> > > > >> to have control of these results as well. E.g. premature
> completion
> > in
> > > > >> case when a result is no longer needed is possible usage.
> > > > >>
> > > > >> Also I thinkg it might be a good time to ponder about
> Future/Promise
> > > > >> APIs in general. Why such API is our choice? Can we choose e.g.
> > > > >> Reactive API style instead?
> > > > >>
> > > > >> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> > > > >> [hidden email]>:
> > > > >> > Andrey,
> > > > >> >
> > > > >> > I see. So in a nutshell, you're saying that we want to return a
> > > future
> > > > >> that
> > > > >> > the user's code is not allowed to complete. In this case, I
> think
> > > it's
> > > > >> > clear that CompletableFuture is not what we need. We actually
> > need a
> > > > >> > NonCompletableFuture :)
> > > > >> >
> > > > >> > My vote is for the custom interface.
> > > > >> >
> > > > >> > -Val
> > > > >> >
> > > > >> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> > > > >> > <[hidden email]>
> > > > >> > wrote:
> > > > >> >
> > > > >> >> Val,
> > > > >> >>
> > > > >> >> The methods below shouldn't be accessible for user:
> > > > >> >> complete()
> > > > >> >> completeExceptionaly()
> > > > >> >>
> > > > >> >> Returning CompletableFuture we must always make a copy to
> prevent
> > > the
> > > > >> >> original future from being completed by mistake.
> > > > >> >> I think it will NOT be enough to do that returing the future to
> > the
> > > > >> >> end-user, but from every critical module to the outside of the
> > > > module,
> > > > >> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> > > > >> >> PartitionReleaseFuture to plugins may be serious.
> > > > >> >>
> > > > >> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
> > > > >> >> implementation
> > > > >> >> will just wrap CompletableFuture these issues will be resolved
> in
> > > > >> natural
> > > > >> >> way.
> > > > >> >> In addition we can force toCompletableFuture() method to
> return a
> > > > >> >> defensive
> > > > >> >> copy(), that resolves the last concern.
> > > > >> >>
> > > > >> >>
> > > > >> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
> > > > >> >> <[hidden email]>
> > > > >> >> wrote:
> > > > >> >>
> > > > >> >> > CompletableFuture seems a better option to me.
> > > > >> >> >
> > > > >> >> > --
> > > > >> >> > Regards,
> > > > >> >> > Konstantin Orlov
> > > > >> >> >
> > > > >> >> >
> > > > >> >> >
> > > > >> >> >
> > > > >> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <
> > [hidden email]
> > > >
> > > > >> >> > > wrote:
> > > > >> >> > >
> > > > >> >> > > On the one hand, I agree with Alexey.
> > > > >> >> > > CompletableFuture has complete* methods which should not be
> > > > >> available
> > > > >> >> to
> > > > >> >> > > the user code.
> > > > >> >> > > This can be solved with a simple interface like we do in
> Thin
> > > > >> Client:
> > > > >> >> > > IgniteClientFuture<T> extends Future<T>, CompletionStage<T>
> > > > >> >> > >
> > > > >> >> > >
> > > > >> >> > > On the other hand:
> > > > >> >> > > - CompletionStage has toCompletableFuture anyway (rather
> > weird)
> > > > >> >> > > - Other libraries use CompletableFuture and it seems to be
> > fine
> > > > >> >> > > - Using CompletableFuture is the simplest approach
> > > > >> >> > >
> > > > >> >> > >
> > > > >> >> > > So I lean towards CompletableFuture too.
> > > > >> >> > >
> > > > >> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> > > > >> >> > [hidden email]>
> > > > >> >> > > wrote:
> > > > >> >> > >
> > > > >> >> > >> I do not like Java's CompletableFuture and prefer our own
> > > Future
> > > > >> >> > (revised
> > > > >> >> > >> IgniteFuture).
> > > > >> >> > >>
> > > > >> >> > >> My understanding of the Future (or Promise) pattern in
> > general
> > > > is
> > > > >> >> having
> > > > >> >> > >> two separate APIs:
> > > > >> >> > >>
> > > > >> >> > >>   1. Server-side: create, set result, raise error, cancel
> > from
> > > > >> >> > >> server.
> > > > >> >> > >>   2. Client-side: get result, handle error, cancel from
> > client
> > > > >> >> > >>
> > > > >> >> > >> Java's CompletableFuture looks like both the client-side
> and
> > > > >> >> > >> server-side API. The "Completeable" prefix in the name is
> > > > already
> > > > >> >> > confusing
> > > > >> >> > >> for a client since it cannot "complete" an operation,
> only a
> > > > >> >> > >> server
> > > > >> >> can.
> > > > >> >> > >>
> > > > >> >> > >> I would create our own IgniteFuture adding client-side
> > > > >> functionality
> > > > >> >> we
> > > > >> >> > >> currently miss (like client-side cancellation).
> > > > >> >> > >>
> > > > >> >> > >>
> > > > >> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> > > > >> >> > >> [hidden email]>:
> > > > >> >> > >>
> > > > >> >> > >>> Andrey,
> > > > >> >> > >>>
> > > > >> >> > >>> Can you compile a full list of these risky methods, and
> > > > >> >> > >>> elaborate
> > > > >> >> > >>> on
> > > > >> >> > what
> > > > >> >> > >>> the risks are?
> > > > >> >> > >>>
> > > > >> >> > >>> Generally, CompletableFuture is a much better option,
> > because
> > > > >> >> > >>> it's
> > > > >> >> > >>> standard. But we need to make sure it actually fits our
> > needs
> > > > >> >> > >>> and
> > > > >> >> > doesn't
> > > > >> >> > >>> do more harm than good.
> > > > >> >> > >>>
> > > > >> >> > >>> -Val
> > > > >> >> > >>>
> > > > >> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> > > > >> >> > >>> [hidden email]> wrote:
> > > > >> >> > >>>
> > > > >> >> > >>>> I think both options are fine, but personally lean
> toward
> > > > >> >> > >>>> CompletableFuture.
> > > > >> >> > >>>>
> > > > >> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <
> [hidden email]
> > >:
> > > > >> >> > >>>>
> > > > >> >> > >>>>> I would suggest using CompletableFuture -- I don't see
> a
> > > need
> > > > >> for
> > > > >> >> > >>>>> a
> > > > >> >> > >>>> custom
> > > > >> >> > >>>>> interface that is unique to us.
> > > > >> >> > >>>>>
> > > > >> >> > >>>>> It also allows a lower barrier for new contributors for
> > > > >> >> understanding
> > > > >> >> > >>>>> existing code
> > > > >> >> > >>>>>
> > > > >> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > > > >> >> > >>> [hidden email]
> > > > >> >> > >>>>>
> > > > >> >> > >>>>> wrote:
> > > > >> >> > >>>>>
> > > > >> >> > >>>>>> Hi Igniters,
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> I'd like to start a discussion about replacing our
> > custom
> > > > >> >> > >>> IgniteFuture
> > > > >> >> > >>>>>> class with CompletableFuture - existed JDK class
> > > > >> >> > >>>>>> or rework it's implementation (like some other
> products
> > > > done)
> > > > >> to
> > > > >> >> > >>>>>> a
> > > > >> >> > >>>>>> composition of CompletionStage and Future interfaces.
> > > > >> >> > >>>>>> or maybe other option if you have any ideas. Do you?
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> 1. The first approach pros and cons are
> > > > >> >> > >>>>>> + Well-known JDK class
> > > > >> >> > >>>>>> + Already implemented
> > > > >> >> > >>>>>> - It is a class, not an interface.
> > > > >> >> > >>>>>> - Expose some potentially harmful methods like
> > > "complete()".
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> On the other side, it has copy() method to create
> > > defensive
> > > > >> copy
> > > > >> >> > >> and
> > > > >> >> > >>>>>> minimalCompletionStage() to restrict harmful method
> > usage.
> > > > >> >> > >>>>>> Thus, this look like an applicable solution, but we
> > should
> > > > be
> > > > >> >> > >> careful
> > > > >> >> > >>>>>> exposing internal future to the outside.
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> 2. The second approach is to implement our own
> interface
> > > > like
> > > > >> >> > >>>>>> the
> > > > >> >> > >>> next
> > > > >> >> > >>>>> one:
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> interface IgniteFuture<T> extends CompletableStage<T>,
> > > > >> Future<T>
> > > > >> >> > >>>>>> {
> > > > >> >> > >>>>>> }
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> Pros and cons are
> > > > >> >> > >>>>>> + Our interfaces/classes contracts will expose an
> > > interface
> > > > >> >> > >>>>>> rather
> > > > >> >> > >>> than
> > > > >> >> > >>>>>> concrete implementation.
> > > > >> >> > >>>>>> + All methods are safe.
> > > > >> >> > >>>>>> - Some implementation is required.
> > > > >> >> > >>>>>> - CompletableStage has a method toCompletableFuture()
> > and
> > > > can
> > > > >> be
> > > > >> >> > >>>>> converted
> > > > >> >> > >>>>>> to CompletableFuture. This should be supported.
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> However, we still could wrap CompletableFuture and
> don't
> > > > >> >> > >>>>>> bother
> > > > >> >> > >> about
> > > > >> >> > >>>>>> creating a defensive copy.
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> Other project experience:
> > > > >> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> > > > >> >> > >>>>>> * Redis goes the second approach [2]
> > > > >> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3].
> > However,
> > > > >> >> > >>>>>> they
> > > > >> >> > >> have
> > > > >> >> > >>>>> custom
> > > > >> >> > >>>>>> future classes and a number of helpers that could be
> > > > replaced
> > > > >> >> > >>>>>> with
> > > > >> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> Any thoughts?
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>> [1]
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>
> > > > >> >> > >>
> > > > >> >> >
> > > > >> >>
> > > > >>
> > > >
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > > >> >> > >>>>>> [2]
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>
> > > > >> >> > >>
> > > > >> >> >
> > > > >> >>
> > > > >>
> > > >
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > > >> >> > >>>>>> [3]
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>
> > > > >> >> > >>
> > > > >> >> >
> > > > >> >>
> > > > >>
> > > >
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > > >> >> > >>>>>> --
> > > > >> >> > >>>>>> Best regards,
> > > > >> >> > >>>>>> Andrey V. Mashenkov
> > > > >> >> > >>>>>>
> > > > >> >> > >>>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>>
> > > > >> >> > >>>> --
> > > > >> >> > >>>>
> > > > >> >> > >>>> Best regards,
> > > > >> >> > >>>> Alexei Scherbakov
> > > > >> >> > >>>>
> > > > >> >> > >>>
> > > > >> >> > >>
> > > > >> >> > >>
> > > > >> >> > >> --
> > > > >> >> > >> Best regards,
> > > > >> >> > >> Alexey
> > > > >> >> > >>
> > > > >> >> >
> > > > >> >> >
> > > > >> >>
> > > > >> >> --
> > > > >> >> Best regards,
> > > > >> >> Andrey V. Mashenkov
> > > > >> >>
> > > > >> >
> > > > >>
> > > > >>
> > > > >> --
> > > > >>
> > > > >> Best regards,
> > > > >> Ivan Pavlukhin
> > > > >>
> > > > >
> > > >
> > > >
> > > > --
> > > >
> > > > Best regards,
> > > > Ivan Pavlukhin
> > > >
> > >
> >
> >
> > --
> > Best regards,
> > Andrey V. Mashenkov
> >
>

--
Regards,

Atri
Apache Concerted

[Denis Garus]

> Completing future from outside will never respect other subscribers that
> may expect other guatantees.

For example, if we talk about public API like IgniteCache, what subscribers
may expect other guatantees?
IMHO, the best solution is to get the well-known standard interface to a
user, and he will be happy.

But when we talk about internal classes like "exchange future" they could
be custom futures if convenient.

вт, 30 мар. 2021 г. в 15:25, Atri Sharma <[hidden email]>:

> IMO the only way Ignite should cancel computations is iff cancel method is
> invoked, not implicitly if complete is invoked.
>
> On Tue, 30 Mar 2021 at 4:58 PM, Denis Garus <[hidden email]> wrote:
>
> > Hello!
> >
> > > Let's say a user started a compute with fut = compute.runAsync(task);
> > > and now calls fut.complete(someVal); Does this mean that Ignite no
> longer
> > needs to execute the task?
> > > If the task is currently running, does it need to be canceled?
> >
> > Yes, this case looks like Ignite should cancel computations because a
> user
> > wants to complete the future. Why not?
> > If there will be an opportunity to cancel a future, why is it a bad
> option
> > to finish a future through a complete() method?
> >
> > > If you look at Ignite-2 code, you may found a number of places where we
> > return e.g. exchange futures or partition release futures.
> > > Assume the impact if we will return CompletableFuture instead, which
> can
> > be completed in 3-rd party plugin by mistake?
> >
> > If exchange futures or partition release futures can be returned to 3-rd
> > party plugin by mistake, it is poor encapsulation.
> > And if it will be IgniteFuter rather than CompletedFuture, anyway, this
> can
> > harm.
> >
> > вт, 30 мар. 2021 г. в 13:14, Andrey Mashenkov <
> [hidden email]
> > >:
> >
> > > Guys,
> > >
> > > I want to remember there is one more point to pay attention to.
> > > Extending Future and CompletableStage is more than just prevents
> > unexpected
> > > behavior if a user completed the future.
> > >
> > > First of all, it helps us to write safer code as we won't a method
> > contract
> > > exposed such methods as to a user as to a developer.
> > > If you look at Ignite-2 code, you may found a number of places where we
> > > return e.g. exchange futures or partition release futures.
> > > Assume the impact if we will return CompletableFuture instead, which
> can
> > be
> > > completed in 3-rd party plugin by mistake?
> > >
> > > The suggested approach allows us to don't bother if a CompletableFuture
> > has
> > > to be wrapped or not.
> > >
> > >
> > > On Tue, Mar 30, 2021 at 12:22 PM Alexey Goncharuk <
> > > [hidden email]> wrote:
> > >
> > > > Ivan,
> > > >
> > > > My concern with the concept of a user completing the future returned
> > from
> > > > Ignite public API is that it is unclear how to interpret this action
> > > (this
> > > > backs Val's message).
> > > > Let's say a user started a compute with fut = compute.runAsync(task);
> > and
> > > > now calls fut.complete(someVal); Does this mean that Ignite no longer
> > > needs
> > > > to execute the task? If the task is currently running, does it need
> to
> > be
> > > > canceled?
> > > >
> > > > Using CompletableFuture.anyOf() is a good instrument in this case
> > because
> > > > it makes the 'first future wins' contract explicit in the code.
> Besides
> > > > that, the point regarding the cancel() method is valid, and we will
> > need
> > > > some custom mechanics to cancel a computation, so a custom interface
> > that
> > > > simply extends both Future and CompletableStage seems reasonable to
> me.
> > > >
> > > > --AG
> > > >
> > > > пн, 29 мар. 2021 г. в 09:12, Ivan Pavlukhin <[hidden email]>:
> > > >
> > > > > Val,
> > > > >
> > > > > There were enough hype around Reactive programming past years. I
> > > > > remind a lot of talks about RxJava. And I suppose it worth to
> > consider
> > > > > it. But it requires some time to study modern trends to make a
> > choice.
> > > > > So far I am not ready to facilitate Reactive API for Ignite 3.
> > > > >
> > > > > Regarding CompletableFuture.
> > > > >
> > > > > > The point is that currently a future returned from any of
> Ignite's
> > > > async
> > > > > > operations is supposed to be completed with a value only by
> Ignite
> > > > > itself,
> > > > > > not by the user. If we follow the same approach in Ignite 3,
> > > returning
> > > > > > CompletableFuture is surely wrong in my view.
> > > > >
> > > > > My first thoughts was similar. But later I thought what a user
> would
> > > > > like do with returned future. And one of cases I imagined was a
> case
> > > > > of alternative result. E.g. a user uses Ignite and another data
> > source
> > > > > in his application. He wants to use a value arrived faster. He
> > > > > combines 2 futures like CompletableFuture.anyOf(...). Consequently
> > > > > even if we prohibit CompletableFuture.complete(...) explicitly then
> > it
> > > > > will be possible to create a combination that will allow premature
> > > > > future completion. After all generally CompletableFuture is a
> > > > > placeholder for async computaion result and if a user wants to
> > > > > substitute result returned from Ignite why should we disallow him
> to
> > > > > do it?
> > > > >
> > > > > Also I found one more suspicious thing with CompletableFuture. As
> it
> > > > > is a concrete class it implements a cancel() method. And as I see
> the
> > > > > implementation does not try to cancel underlying computations. Is
> not
> > > > > it a problem?
> > > > >
> > > > > 2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <
> > > > > [hidden email]>:
> > > > > > Ivan,
> > > > > >
> > > > > > It's not really about the "harm", but more about "what should we
> do
> > > if
> > > > > this
> > > > > > method is called?". Imagine the following code:
> > > > > >
> > > > > > CompletableFuture<String> fut = cache.getAsync(key);
> > > > > > fut.complete("something");
> > > > > >
> > > > > > What should happen in this case?
> > > > > >
> > > > > > The point is that currently a future returned from any of
> Ignite's
> > > > async
> > > > > > operations is supposed to be completed with a value only by
> Ignite
> > > > > itself,
> > > > > > not by the user. If we follow the same approach in Ignite 3,
> > > returning
> > > > > > CompletableFuture is surely wrong in my view.
> > > > > >
> > > > > > At the same time, if we take a fundamentally different route with
> > the
> > > > > async
> > > > > > APIs, this whole discussion might become irrelevant. For example,
> > can
> > > > you
> > > > > > elaborate on your thinking around the reactive API? Do you have
> any
> > > > > > specifics in mind?
> > > > > >
> > > > > > -Val
> > > > > >
> > > > > > On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <
> > [hidden email]>
> > > > > wrote:
> > > > > >
> > > > > >> > The methods below shouldn't be accessible for user:
> > > > > >> > complete()
> > > > > >> > completeExceptionaly()
> > > > > >>
> > > > > >> Folks, in case of user-facing API, do you think there is a real
> > harm
> > > > > >> in allowing a user to manually "complete" a future? I suppose a
> > user
> > > > > >> employs some post-processing for future results and potentially
> > > wants
> > > > > >> to have control of these results as well. E.g. premature
> > completion
> > > in
> > > > > >> case when a result is no longer needed is possible usage.
> > > > > >>
> > > > > >> Also I thinkg it might be a good time to ponder about
> > Future/Promise
> > > > > >> APIs in general. Why such API is our choice? Can we choose e.g.
> > > > > >> Reactive API style instead?
> > > > > >>
> > > > > >> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> > > > > >> [hidden email]>:
> > > > > >> > Andrey,
> > > > > >> >
> > > > > >> > I see. So in a nutshell, you're saying that we want to return
> a
> > > > future
> > > > > >> that
> > > > > >> > the user's code is not allowed to complete. In this case, I
> > think
> > > > it's
> > > > > >> > clear that CompletableFuture is not what we need. We actually
> > > need a
> > > > > >> > NonCompletableFuture :)
> > > > > >> >
> > > > > >> > My vote is for the custom interface.
> > > > > >> >
> > > > > >> > -Val
> > > > > >> >
> > > > > >> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> > > > > >> > <[hidden email]>
> > > > > >> > wrote:
> > > > > >> >
> > > > > >> >> Val,
> > > > > >> >>
> > > > > >> >> The methods below shouldn't be accessible for user:
> > > > > >> >> complete()
> > > > > >> >> completeExceptionaly()
> > > > > >> >>
> > > > > >> >> Returning CompletableFuture we must always make a copy to
> > prevent
> > > > the
> > > > > >> >> original future from being completed by mistake.
> > > > > >> >> I think it will NOT be enough to do that returing the future
> to
> > > the
> > > > > >> >> end-user, but from every critical module to the outside of
> the
> > > > > module,
> > > > > >> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> > > > > >> >> PartitionReleaseFuture to plugins may be serious.
> > > > > >> >>
> > > > > >> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
> > > > > >> >> implementation
> > > > > >> >> will just wrap CompletableFuture these issues will be
> resolved
> > in
> > > > > >> natural
> > > > > >> >> way.
> > > > > >> >> In addition we can force toCompletableFuture() method to
> > return a
> > > > > >> >> defensive
> > > > > >> >> copy(), that resolves the last concern.
> > > > > >> >>
> > > > > >> >>
> > > > > >> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
> > > > > >> >> <[hidden email]>
> > > > > >> >> wrote:
> > > > > >> >>
> > > > > >> >> > CompletableFuture seems a better option to me.
> > > > > >> >> >
> > > > > >> >> > --
> > > > > >> >> > Regards,
> > > > > >> >> > Konstantin Orlov
> > > > > >> >> >
> > > > > >> >> >
> > > > > >> >> >
> > > > > >> >> >
> > > > > >> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <
> > > [hidden email]
> > > > >
> > > > > >> >> > > wrote:
> > > > > >> >> > >
> > > > > >> >> > > On the one hand, I agree with Alexey.
> > > > > >> >> > > CompletableFuture has complete* methods which should not
> be
> > > > > >> available
> > > > > >> >> to
> > > > > >> >> > > the user code.
> > > > > >> >> > > This can be solved with a simple interface like we do in
> > Thin
> > > > > >> Client:
> > > > > >> >> > > IgniteClientFuture<T> extends Future<T>,
> CompletionStage<T>
> > > > > >> >> > >
> > > > > >> >> > >
> > > > > >> >> > > On the other hand:
> > > > > >> >> > > - CompletionStage has toCompletableFuture anyway (rather
> > > weird)
> > > > > >> >> > > - Other libraries use CompletableFuture and it seems to
> be
> > > fine
> > > > > >> >> > > - Using CompletableFuture is the simplest approach
> > > > > >> >> > >
> > > > > >> >> > >
> > > > > >> >> > > So I lean towards CompletableFuture too.
> > > > > >> >> > >
> > > > > >> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> > > > > >> >> > [hidden email]>
> > > > > >> >> > > wrote:
> > > > > >> >> > >
> > > > > >> >> > >> I do not like Java's CompletableFuture and prefer our
> own
> > > > Future
> > > > > >> >> > (revised
> > > > > >> >> > >> IgniteFuture).
> > > > > >> >> > >>
> > > > > >> >> > >> My understanding of the Future (or Promise) pattern in
> > > general
> > > > > is
> > > > > >> >> having
> > > > > >> >> > >> two separate APIs:
> > > > > >> >> > >>
> > > > > >> >> > >>   1. Server-side: create, set result, raise error,
> cancel
> > > from
> > > > > >> >> > >> server.
> > > > > >> >> > >>   2. Client-side: get result, handle error, cancel from
> > > client
> > > > > >> >> > >>
> > > > > >> >> > >> Java's CompletableFuture looks like both the client-side
> > and
> > > > > >> >> > >> server-side API. The "Completeable" prefix in the name
> is
> > > > > already
> > > > > >> >> > confusing
> > > > > >> >> > >> for a client since it cannot "complete" an operation,
> > only a
> > > > > >> >> > >> server
> > > > > >> >> can.
> > > > > >> >> > >>
> > > > > >> >> > >> I would create our own IgniteFuture adding client-side
> > > > > >> functionality
> > > > > >> >> we
> > > > > >> >> > >> currently miss (like client-side cancellation).
> > > > > >> >> > >>
> > > > > >> >> > >>
> > > > > >> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> > > > > >> >> > >> [hidden email]>:
> > > > > >> >> > >>
> > > > > >> >> > >>> Andrey,
> > > > > >> >> > >>>
> > > > > >> >> > >>> Can you compile a full list of these risky methods, and
> > > > > >> >> > >>> elaborate
> > > > > >> >> > >>> on
> > > > > >> >> > what
> > > > > >> >> > >>> the risks are?
> > > > > >> >> > >>>
> > > > > >> >> > >>> Generally, CompletableFuture is a much better option,
> > > because
> > > > > >> >> > >>> it's
> > > > > >> >> > >>> standard. But we need to make sure it actually fits our
> > > needs
> > > > > >> >> > >>> and
> > > > > >> >> > doesn't
> > > > > >> >> > >>> do more harm than good.
> > > > > >> >> > >>>
> > > > > >> >> > >>> -Val
> > > > > >> >> > >>>
> > > > > >> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> > > > > >> >> > >>> [hidden email]> wrote:
> > > > > >> >> > >>>
> > > > > >> >> > >>>> I think both options are fine, but personally lean
> > toward
> > > > > >> >> > >>>> CompletableFuture.
> > > > > >> >> > >>>>
> > > > > >> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <
> > [hidden email]
> > > >:
> > > > > >> >> > >>>>
> > > > > >> >> > >>>>> I would suggest using CompletableFuture -- I don't
> see
> > a
> > > > need
> > > > > >> for
> > > > > >> >> > >>>>> a
> > > > > >> >> > >>>> custom
> > > > > >> >> > >>>>> interface that is unique to us.
> > > > > >> >> > >>>>>
> > > > > >> >> > >>>>> It also allows a lower barrier for new contributors
> for
> > > > > >> >> understanding
> > > > > >> >> > >>>>> existing code
> > > > > >> >> > >>>>>
> > > > > >> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > > > > >> >> > >>> [hidden email]
> > > > > >> >> > >>>>>
> > > > > >> >> > >>>>> wrote:
> > > > > >> >> > >>>>>
> > > > > >> >> > >>>>>> Hi Igniters,
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> I'd like to start a discussion about replacing our
> > > custom
> > > > > >> >> > >>> IgniteFuture
> > > > > >> >> > >>>>>> class with CompletableFuture - existed JDK class
> > > > > >> >> > >>>>>> or rework it's implementation (like some other
> > products
> > > > > done)
> > > > > >> to
> > > > > >> >> > >>>>>> a
> > > > > >> >> > >>>>>> composition of CompletionStage and Future
> interfaces.
> > > > > >> >> > >>>>>> or maybe other option if you have any ideas. Do you?
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> 1. The first approach pros and cons are
> > > > > >> >> > >>>>>> + Well-known JDK class
> > > > > >> >> > >>>>>> + Already implemented
> > > > > >> >> > >>>>>> - It is a class, not an interface.
> > > > > >> >> > >>>>>> - Expose some potentially harmful methods like
> > > > "complete()".
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> On the other side, it has copy() method to create
> > > > defensive
> > > > > >> copy
> > > > > >> >> > >> and
> > > > > >> >> > >>>>>> minimalCompletionStage() to restrict harmful method
> > > usage.
> > > > > >> >> > >>>>>> Thus, this look like an applicable solution, but we
> > > should
> > > > > be
> > > > > >> >> > >> careful
> > > > > >> >> > >>>>>> exposing internal future to the outside.
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> 2. The second approach is to implement our own
> > interface
> > > > > like
> > > > > >> >> > >>>>>> the
> > > > > >> >> > >>> next
> > > > > >> >> > >>>>> one:
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> interface IgniteFuture<T> extends
> CompletableStage<T>,
> > > > > >> Future<T>
> > > > > >> >> > >>>>>> {
> > > > > >> >> > >>>>>> }
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> Pros and cons are
> > > > > >> >> > >>>>>> + Our interfaces/classes contracts will expose an
> > > > interface
> > > > > >> >> > >>>>>> rather
> > > > > >> >> > >>> than
> > > > > >> >> > >>>>>> concrete implementation.
> > > > > >> >> > >>>>>> + All methods are safe.
> > > > > >> >> > >>>>>> - Some implementation is required.
> > > > > >> >> > >>>>>> - CompletableStage has a method
> toCompletableFuture()
> > > and
> > > > > can
> > > > > >> be
> > > > > >> >> > >>>>> converted
> > > > > >> >> > >>>>>> to CompletableFuture. This should be supported.
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> However, we still could wrap CompletableFuture and
> > don't
> > > > > >> >> > >>>>>> bother
> > > > > >> >> > >> about
> > > > > >> >> > >>>>>> creating a defensive copy.
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> Other project experience:
> > > > > >> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> > > > > >> >> > >>>>>> * Redis goes the second approach [2]
> > > > > >> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3].
> > > However,
> > > > > >> >> > >>>>>> they
> > > > > >> >> > >> have
> > > > > >> >> > >>>>> custom
> > > > > >> >> > >>>>>> future classes and a number of helpers that could be
> > > > > replaced
> > > > > >> >> > >>>>>> with
> > > > > >> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> Any thoughts?
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>> [1]
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>
> > > > > >> >> > >>>>
> > > > > >> >> > >>>
> > > > > >> >> > >>
> > > > > >> >> >
> > > > > >> >>
> > > > > >>
> > > > >
> > > >
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > > > >> >> > >>>>>> [2]
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>
> > > > > >> >> > >>>>
> > > > > >> >> > >>>
> > > > > >> >> > >>
> > > > > >> >> >
> > > > > >> >>
> > > > > >>
> > > > >
> > > >
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > > > >> >> > >>>>>> [3]
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>
> > > > > >> >> > >>>>
> > > > > >> >> > >>>
> > > > > >> >> > >>
> > > > > >> >> >
> > > > > >> >>
> > > > > >>
> > > > >
> > > >
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > > > >> >> > >>>>>> --
> > > > > >> >> > >>>>>> Best regards,
> > > > > >> >> > >>>>>> Andrey V. Mashenkov
> > > > > >> >> > >>>>>>
> > > > > >> >> > >>>>>
> > > > > >> >> > >>>>
> > > > > >> >> > >>>>
> > > > > >> >> > >>>> --
> > > > > >> >> > >>>>
> > > > > >> >> > >>>> Best regards,
> > > > > >> >> > >>>> Alexei Scherbakov
> > > > > >> >> > >>>>
> > > > > >> >> > >>>
> > > > > >> >> > >>
> > > > > >> >> > >>
> > > > > >> >> > >> --
> > > > > >> >> > >> Best regards,
> > > > > >> >> > >> Alexey
> > > > > >> >> > >>
> > > > > >> >> >
> > > > > >> >> >
> > > > > >> >>
> > > > > >> >> --
> > > > > >> >> Best regards,
> > > > > >> >> Andrey V. Mashenkov
> > > > > >> >>
> > > > > >> >
> > > > > >>
> > > > > >>
> > > > > >> --
> > > > > >>
> > > > > >> Best regards,
> > > > > >> Ivan Pavlukhin
> > > > > >>
> > > > > >
> > > > >
> > > > >
> > > > > --
> > > > >
> > > > > Best regards,
> > > > > Ivan Pavlukhin
> > > > >
> > > >
> > >
> > >
> > > --
> > > Best regards,
> > > Andrey V. Mashenkov
> > >
> >
> --
> Regards,
>
> Atri
> Apache Concerted
>

[Valentin Kulichenko]

These are actually some interesting points. As I'm thinking more about
this, I'm leaning towards changing my opinion and voting for the
CompletableFuture. Here is my reasoning.

First, it's important to keep in mind that CompletableFuture is not an
interface that we will implement, it's an implemented class. Therefore,
some of the concerns around complete() and cancel() method are not really
relevant -- it's not up to us how these methods behave, they're already
implemented.

Second, CompletableFuture does provide some useful functionality (anyOf is
one of the examples). I can even envision users wanting to complete the
future under certain circumstances, e.g. after a timeout, using
the completeOnTimeout method. Stripping them from such functionality, which
they are used to, is most likely a bad idea.

And finally, we can have an IgniteFuture that extends CompletableFuture.
This might be useful if want the cancel() operation to cancel the
underlying operation. This way we keep all the functionality of
CompletableFuture while keeping a certain amount of flexibility for
specific cases.

Thoughts?

-Val


On Tue, Mar 30, 2021 at 5:36 AM Denis Garus <[hidden email]> wrote:

> > Completing future from outside will never respect other subscribers that
> > may expect other guatantees.
>
> For example, if we talk about public API like IgniteCache, what subscribers
> may expect other guatantees?
> IMHO, the best solution is to get the well-known standard interface to a
> user, and he will be happy.
>
> But when we talk about internal classes like "exchange future" they could
> be custom futures if convenient.
>
> вт, 30 мар. 2021 г. в 15:25, Atri Sharma <[hidden email]>:
>
> > IMO the only way Ignite should cancel computations is iff cancel method
> is
> > invoked, not implicitly if complete is invoked.
> >
> > On Tue, 30 Mar 2021 at 4:58 PM, Denis Garus <[hidden email]> wrote:
> >
> > > Hello!
> > >
> > > > Let's say a user started a compute with fut = compute.runAsync(task);
> > > > and now calls fut.complete(someVal); Does this mean that Ignite no
> > longer
> > > needs to execute the task?
> > > > If the task is currently running, does it need to be canceled?
> > >
> > > Yes, this case looks like Ignite should cancel computations because a
> > user
> > > wants to complete the future. Why not?
> > > If there will be an opportunity to cancel a future, why is it a bad
> > option
> > > to finish a future through a complete() method?
> > >
> > > > If you look at Ignite-2 code, you may found a number of places where
> we
> > > return e.g. exchange futures or partition release futures.
> > > > Assume the impact if we will return CompletableFuture instead, which
> > can
> > > be completed in 3-rd party plugin by mistake?
> > >
> > > If exchange futures or partition release futures can be returned to
> 3-rd
> > > party plugin by mistake, it is poor encapsulation.
> > > And if it will be IgniteFuter rather than CompletedFuture, anyway, this
> > can
> > > harm.
> > >
> > > вт, 30 мар. 2021 г. в 13:14, Andrey Mashenkov <
> > [hidden email]
> > > >:
> > >
> > > > Guys,
> > > >
> > > > I want to remember there is one more point to pay attention to.
> > > > Extending Future and CompletableStage is more than just prevents
> > > unexpected
> > > > behavior if a user completed the future.
> > > >
> > > > First of all, it helps us to write safer code as we won't a method
> > > contract
> > > > exposed such methods as to a user as to a developer.
> > > > If you look at Ignite-2 code, you may found a number of places where
> we
> > > > return e.g. exchange futures or partition release futures.
> > > > Assume the impact if we will return CompletableFuture instead, which
> > can
> > > be
> > > > completed in 3-rd party plugin by mistake?
> > > >
> > > > The suggested approach allows us to don't bother if a
> CompletableFuture
> > > has
> > > > to be wrapped or not.
> > > >
> > > >
> > > > On Tue, Mar 30, 2021 at 12:22 PM Alexey Goncharuk <
> > > > [hidden email]> wrote:
> > > >
> > > > > Ivan,
> > > > >
> > > > > My concern with the concept of a user completing the future
> returned
> > > from
> > > > > Ignite public API is that it is unclear how to interpret this
> action
> > > > (this
> > > > > backs Val's message).
> > > > > Let's say a user started a compute with fut =
> compute.runAsync(task);
> > > and
> > > > > now calls fut.complete(someVal); Does this mean that Ignite no
> longer
> > > > needs
> > > > > to execute the task? If the task is currently running, does it need
> > to
> > > be
> > > > > canceled?
> > > > >
> > > > > Using CompletableFuture.anyOf() is a good instrument in this case
> > > because
> > > > > it makes the 'first future wins' contract explicit in the code.
> > Besides
> > > > > that, the point regarding the cancel() method is valid, and we will
> > > need
> > > > > some custom mechanics to cancel a computation, so a custom
> interface
> > > that
> > > > > simply extends both Future and CompletableStage seems reasonable to
> > me.
> > > > >
> > > > > --AG
> > > > >
> > > > > пн, 29 мар. 2021 г. в 09:12, Ivan Pavlukhin <[hidden email]>:
> > > > >
> > > > > > Val,
> > > > > >
> > > > > > There were enough hype around Reactive programming past years. I
> > > > > > remind a lot of talks about RxJava. And I suppose it worth to
> > > consider
> > > > > > it. But it requires some time to study modern trends to make a
> > > choice.
> > > > > > So far I am not ready to facilitate Reactive API for Ignite 3.
> > > > > >
> > > > > > Regarding CompletableFuture.
> > > > > >
> > > > > > > The point is that currently a future returned from any of
> > Ignite's
> > > > > async
> > > > > > > operations is supposed to be completed with a value only by
> > Ignite
> > > > > > itself,
> > > > > > > not by the user. If we follow the same approach in Ignite 3,
> > > > returning
> > > > > > > CompletableFuture is surely wrong in my view.
> > > > > >
> > > > > > My first thoughts was similar. But later I thought what a user
> > would
> > > > > > like do with returned future. And one of cases I imagined was a
> > case
> > > > > > of alternative result. E.g. a user uses Ignite and another data
> > > source
> > > > > > in his application. He wants to use a value arrived faster. He
> > > > > > combines 2 futures like CompletableFuture.anyOf(...).
> Consequently
> > > > > > even if we prohibit CompletableFuture.complete(...) explicitly
> then
> > > it
> > > > > > will be possible to create a combination that will allow
> premature
> > > > > > future completion. After all generally CompletableFuture is a
> > > > > > placeholder for async computaion result and if a user wants to
> > > > > > substitute result returned from Ignite why should we disallow him
> > to
> > > > > > do it?
> > > > > >
> > > > > > Also I found one more suspicious thing with CompletableFuture. As
> > it
> > > > > > is a concrete class it implements a cancel() method. And as I see
> > the
> > > > > > implementation does not try to cancel underlying computations. Is
> > not
> > > > > > it a problem?
> > > > > >
> > > > > > 2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <
> > > > > > [hidden email]>:
> > > > > > > Ivan,
> > > > > > >
> > > > > > > It's not really about the "harm", but more about "what should
> we
> > do
> > > > if
> > > > > > this
> > > > > > > method is called?". Imagine the following code:
> > > > > > >
> > > > > > > CompletableFuture<String> fut = cache.getAsync(key);
> > > > > > > fut.complete("something");
> > > > > > >
> > > > > > > What should happen in this case?
> > > > > > >
> > > > > > > The point is that currently a future returned from any of
> > Ignite's
> > > > > async
> > > > > > > operations is supposed to be completed with a value only by
> > Ignite
> > > > > > itself,
> > > > > > > not by the user. If we follow the same approach in Ignite 3,
> > > > returning
> > > > > > > CompletableFuture is surely wrong in my view.
> > > > > > >
> > > > > > > At the same time, if we take a fundamentally different route
> with
> > > the
> > > > > > async
> > > > > > > APIs, this whole discussion might become irrelevant. For
> example,
> > > can
> > > > > you
> > > > > > > elaborate on your thinking around the reactive API? Do you have
> > any
> > > > > > > specifics in mind?
> > > > > > >
> > > > > > > -Val
> > > > > > >
> > > > > > > On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <
> > > [hidden email]>
> > > > > > wrote:
> > > > > > >
> > > > > > >> > The methods below shouldn't be accessible for user:
> > > > > > >> > complete()
> > > > > > >> > completeExceptionaly()
> > > > > > >>
> > > > > > >> Folks, in case of user-facing API, do you think there is a
> real
> > > harm
> > > > > > >> in allowing a user to manually "complete" a future? I suppose
> a
> > > user
> > > > > > >> employs some post-processing for future results and
> potentially
> > > > wants
> > > > > > >> to have control of these results as well. E.g. premature
> > > completion
> > > > in
> > > > > > >> case when a result is no longer needed is possible usage.
> > > > > > >>
> > > > > > >> Also I thinkg it might be a good time to ponder about
> > > Future/Promise
> > > > > > >> APIs in general. Why such API is our choice? Can we choose
> e.g.
> > > > > > >> Reactive API style instead?
> > > > > > >>
> > > > > > >> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> > > > > > >> [hidden email]>:
> > > > > > >> > Andrey,
> > > > > > >> >
> > > > > > >> > I see. So in a nutshell, you're saying that we want to
> return
> > a
> > > > > future
> > > > > > >> that
> > > > > > >> > the user's code is not allowed to complete. In this case, I
> > > think
> > > > > it's
> > > > > > >> > clear that CompletableFuture is not what we need. We
> actually
> > > > need a
> > > > > > >> > NonCompletableFuture :)
> > > > > > >> >
> > > > > > >> > My vote is for the custom interface.
> > > > > > >> >
> > > > > > >> > -Val
> > > > > > >> >
> > > > > > >> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> > > > > > >> > <[hidden email]>
> > > > > > >> > wrote:
> > > > > > >> >
> > > > > > >> >> Val,
> > > > > > >> >>
> > > > > > >> >> The methods below shouldn't be accessible for user:
> > > > > > >> >> complete()
> > > > > > >> >> completeExceptionaly()
> > > > > > >> >>
> > > > > > >> >> Returning CompletableFuture we must always make a copy to
> > > prevent
> > > > > the
> > > > > > >> >> original future from being completed by mistake.
> > > > > > >> >> I think it will NOT be enough to do that returing the
> future
> > to
> > > > the
> > > > > > >> >> end-user, but from every critical module to the outside of
> > the
> > > > > > module,
> > > > > > >> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> > > > > > >> >> PartitionReleaseFuture to plugins may be serious.
> > > > > > >> >>
> > > > > > >> >> IgniteFuture<T> extends Future<T>, CompletionStage<T> which
> > > > > > >> >> implementation
> > > > > > >> >> will just wrap CompletableFuture these issues will be
> > resolved
> > > in
> > > > > > >> natural
> > > > > > >> >> way.
> > > > > > >> >> In addition we can force toCompletableFuture() method to
> > > return a
> > > > > > >> >> defensive
> > > > > > >> >> copy(), that resolves the last concern.
> > > > > > >> >>
> > > > > > >> >>
> > > > > > >> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
> > > > > > >> >> <[hidden email]>
> > > > > > >> >> wrote:
> > > > > > >> >>
> > > > > > >> >> > CompletableFuture seems a better option to me.
> > > > > > >> >> >
> > > > > > >> >> > --
> > > > > > >> >> > Regards,
> > > > > > >> >> > Konstantin Orlov
> > > > > > >> >> >
> > > > > > >> >> >
> > > > > > >> >> >
> > > > > > >> >> >
> > > > > > >> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <
> > > > [hidden email]
> > > > > >
> > > > > > >> >> > > wrote:
> > > > > > >> >> > >
> > > > > > >> >> > > On the one hand, I agree with Alexey.
> > > > > > >> >> > > CompletableFuture has complete* methods which should
> not
> > be
> > > > > > >> available
> > > > > > >> >> to
> > > > > > >> >> > > the user code.
> > > > > > >> >> > > This can be solved with a simple interface like we do
> in
> > > Thin
> > > > > > >> Client:
> > > > > > >> >> > > IgniteClientFuture<T> extends Future<T>,
> > CompletionStage<T>
> > > > > > >> >> > >
> > > > > > >> >> > >
> > > > > > >> >> > > On the other hand:
> > > > > > >> >> > > - CompletionStage has toCompletableFuture anyway
> (rather
> > > > weird)
> > > > > > >> >> > > - Other libraries use CompletableFuture and it seems to
> > be
> > > > fine
> > > > > > >> >> > > - Using CompletableFuture is the simplest approach
> > > > > > >> >> > >
> > > > > > >> >> > >
> > > > > > >> >> > > So I lean towards CompletableFuture too.
> > > > > > >> >> > >
> > > > > > >> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> > > > > > >> >> > [hidden email]>
> > > > > > >> >> > > wrote:
> > > > > > >> >> > >
> > > > > > >> >> > >> I do not like Java's CompletableFuture and prefer our
> > own
> > > > > Future
> > > > > > >> >> > (revised
> > > > > > >> >> > >> IgniteFuture).
> > > > > > >> >> > >>
> > > > > > >> >> > >> My understanding of the Future (or Promise) pattern in
> > > > general
> > > > > > is
> > > > > > >> >> having
> > > > > > >> >> > >> two separate APIs:
> > > > > > >> >> > >>
> > > > > > >> >> > >>   1. Server-side: create, set result, raise error,
> > cancel
> > > > from
> > > > > > >> >> > >> server.
> > > > > > >> >> > >>   2. Client-side: get result, handle error, cancel
> from
> > > > client
> > > > > > >> >> > >>
> > > > > > >> >> > >> Java's CompletableFuture looks like both the
> client-side
> > > and
> > > > > > >> >> > >> server-side API. The "Completeable" prefix in the name
> > is
> > > > > > already
> > > > > > >> >> > confusing
> > > > > > >> >> > >> for a client since it cannot "complete" an operation,
> > > only a
> > > > > > >> >> > >> server
> > > > > > >> >> can.
> > > > > > >> >> > >>
> > > > > > >> >> > >> I would create our own IgniteFuture adding client-side
> > > > > > >> functionality
> > > > > > >> >> we
> > > > > > >> >> > >> currently miss (like client-side cancellation).
> > > > > > >> >> > >>
> > > > > > >> >> > >>
> > > > > > >> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> > > > > > >> >> > >> [hidden email]>:
> > > > > > >> >> > >>
> > > > > > >> >> > >>> Andrey,
> > > > > > >> >> > >>>
> > > > > > >> >> > >>> Can you compile a full list of these risky methods,
> and
> > > > > > >> >> > >>> elaborate
> > > > > > >> >> > >>> on
> > > > > > >> >> > what
> > > > > > >> >> > >>> the risks are?
> > > > > > >> >> > >>>
> > > > > > >> >> > >>> Generally, CompletableFuture is a much better option,
> > > > because
> > > > > > >> >> > >>> it's
> > > > > > >> >> > >>> standard. But we need to make sure it actually fits
> our
> > > > needs
> > > > > > >> >> > >>> and
> > > > > > >> >> > doesn't
> > > > > > >> >> > >>> do more harm than good.
> > > > > > >> >> > >>>
> > > > > > >> >> > >>> -Val
> > > > > > >> >> > >>>
> > > > > > >> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov <
> > > > > > >> >> > >>> [hidden email]> wrote:
> > > > > > >> >> > >>>
> > > > > > >> >> > >>>> I think both options are fine, but personally lean
> > > toward
> > > > > > >> >> > >>>> CompletableFuture.
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <
> > > [hidden email]
> > > > >:
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>>> I would suggest using CompletableFuture -- I don't
> > see
> > > a
> > > > > need
> > > > > > >> for
> > > > > > >> >> > >>>>> a
> > > > > > >> >> > >>>> custom
> > > > > > >> >> > >>>>> interface that is unique to us.
> > > > > > >> >> > >>>>>
> > > > > > >> >> > >>>>> It also allows a lower barrier for new contributors
> > for
> > > > > > >> >> understanding
> > > > > > >> >> > >>>>> existing code
> > > > > > >> >> > >>>>>
> > > > > > >> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > > > > > >> >> > >>> [hidden email]
> > > > > > >> >> > >>>>>
> > > > > > >> >> > >>>>> wrote:
> > > > > > >> >> > >>>>>
> > > > > > >> >> > >>>>>> Hi Igniters,
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> I'd like to start a discussion about replacing our
> > > > custom
> > > > > > >> >> > >>> IgniteFuture
> > > > > > >> >> > >>>>>> class with CompletableFuture - existed JDK class
> > > > > > >> >> > >>>>>> or rework it's implementation (like some other
> > > products
> > > > > > done)
> > > > > > >> to
> > > > > > >> >> > >>>>>> a
> > > > > > >> >> > >>>>>> composition of CompletionStage and Future
> > interfaces.
> > > > > > >> >> > >>>>>> or maybe other option if you have any ideas. Do
> you?
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> 1. The first approach pros and cons are
> > > > > > >> >> > >>>>>> + Well-known JDK class
> > > > > > >> >> > >>>>>> + Already implemented
> > > > > > >> >> > >>>>>> - It is a class, not an interface.
> > > > > > >> >> > >>>>>> - Expose some potentially harmful methods like
> > > > > "complete()".
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> On the other side, it has copy() method to create
> > > > > defensive
> > > > > > >> copy
> > > > > > >> >> > >> and
> > > > > > >> >> > >>>>>> minimalCompletionStage() to restrict harmful
> method
> > > > usage.
> > > > > > >> >> > >>>>>> Thus, this look like an applicable solution, but
> we
> > > > should
> > > > > > be
> > > > > > >> >> > >> careful
> > > > > > >> >> > >>>>>> exposing internal future to the outside.
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> 2. The second approach is to implement our own
> > > interface
> > > > > > like
> > > > > > >> >> > >>>>>> the
> > > > > > >> >> > >>> next
> > > > > > >> >> > >>>>> one:
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> interface IgniteFuture<T> extends
> > CompletableStage<T>,
> > > > > > >> Future<T>
> > > > > > >> >> > >>>>>> {
> > > > > > >> >> > >>>>>> }
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> Pros and cons are
> > > > > > >> >> > >>>>>> + Our interfaces/classes contracts will expose an
> > > > > interface
> > > > > > >> >> > >>>>>> rather
> > > > > > >> >> > >>> than
> > > > > > >> >> > >>>>>> concrete implementation.
> > > > > > >> >> > >>>>>> + All methods are safe.
> > > > > > >> >> > >>>>>> - Some implementation is required.
> > > > > > >> >> > >>>>>> - CompletableStage has a method
> > toCompletableFuture()
> > > > and
> > > > > > can
> > > > > > >> be
> > > > > > >> >> > >>>>> converted
> > > > > > >> >> > >>>>>> to CompletableFuture. This should be supported.
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> However, we still could wrap CompletableFuture and
> > > don't
> > > > > > >> >> > >>>>>> bother
> > > > > > >> >> > >> about
> > > > > > >> >> > >>>>>> creating a defensive copy.
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> Other project experience:
> > > > > > >> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> > > > > > >> >> > >>>>>> * Redis goes the second approach [2]
> > > > > > >> >> > >>>>>> * Vertx explicitly extends CompletableFuture [3].
> > > > However,
> > > > > > >> >> > >>>>>> they
> > > > > > >> >> > >> have
> > > > > > >> >> > >>>>> custom
> > > > > > >> >> > >>>>>> future classes and a number of helpers that could
> be
> > > > > > replaced
> > > > > > >> >> > >>>>>> with
> > > > > > >> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> Any thoughts?
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>> [1]
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>
> > > > > > >> >> > >>
> > > > > > >> >> >
> > > > > > >> >>
> > > > > > >>
> > > > > >
> > > > >
> > > >
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > > > > >> >> > >>>>>> [2]
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>
> > > > > > >> >> > >>
> > > > > > >> >> >
> > > > > > >> >>
> > > > > > >>
> > > > > >
> > > > >
> > > >
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > > > > >> >> > >>>>>> [3]
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>
> > > > > > >> >> > >>
> > > > > > >> >> >
> > > > > > >> >>
> > > > > > >>
> > > > > >
> > > > >
> > > >
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > > > > >> >> > >>>>>> --
> > > > > > >> >> > >>>>>> Best regards,
> > > > > > >> >> > >>>>>> Andrey V. Mashenkov
> > > > > > >> >> > >>>>>>
> > > > > > >> >> > >>>>>
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>> --
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>> Best regards,
> > > > > > >> >> > >>>> Alexei Scherbakov
> > > > > > >> >> > >>>>
> > > > > > >> >> > >>>
> > > > > > >> >> > >>
> > > > > > >> >> > >>
> > > > > > >> >> > >> --
> > > > > > >> >> > >> Best regards,
> > > > > > >> >> > >> Alexey
> > > > > > >> >> > >>
> > > > > > >> >> >
> > > > > > >> >> >
> > > > > > >> >>
> > > > > > >> >> --
> > > > > > >> >> Best regards,
> > > > > > >> >> Andrey V. Mashenkov
> > > > > > >> >>
> > > > > > >> >
> > > > > > >>
> > > > > > >>
> > > > > > >> --
> > > > > > >>
> > > > > > >> Best regards,
> > > > > > >> Ivan Pavlukhin
> > > > > > >>
> > > > > > >
> > > > > >
> > > > > >
> > > > > > --
> > > > > >
> > > > > > Best regards,
> > > > > > Ivan Pavlukhin
> > > > > >
> > > > >
> > > >
> > > >
> > > > --
> > > > Best regards,
> > > > Andrey V. Mashenkov
> > > >
> > >
> > --
> > Regards,
> >
> > Atri
> > Apache Concerted
> >
>

[Pavel Tupitsyn]

Val,

> we can have an IgniteFuture that extends CompletableFuture.
> This might be useful if want the cancel() operation to cancel the
> underlying operation

I think we can subscribe to the cancellation of the CompletableFuture
and cancel the underlying operation without an extra class,
something like

        fut.exceptionally(t -> {
            if (t instanceof CancellationException) {
                // Cancel Ignite operation
            }
        });

On Wed, Mar 31, 2021 at 7:45 AM Valentin Kulichenko <
[hidden email]> wrote:

> These are actually some interesting points. As I'm thinking more about
> this, I'm leaning towards changing my opinion and voting for the
> CompletableFuture. Here is my reasoning.
>
> First, it's important to keep in mind that CompletableFuture is not an
> interface that we will implement, it's an implemented class. Therefore,
> some of the concerns around complete() and cancel() method are not really
> relevant -- it's not up to us how these methods behave, they're already
> implemented.
>
> Second, CompletableFuture does provide some useful functionality (anyOf is
> one of the examples). I can even envision users wanting to complete the
> future under certain circumstances, e.g. after a timeout, using
> the completeOnTimeout method. Stripping them from such functionality, which
> they are used to, is most likely a bad idea.
>
> And finally, we can have an IgniteFuture that extends CompletableFuture.
> This might be useful if want the cancel() operation to cancel the
> underlying operation. This way we keep all the functionality of
> CompletableFuture while keeping a certain amount of flexibility for
> specific cases.
>
> Thoughts?
>
> -Val
>
>
> On Tue, Mar 30, 2021 at 5:36 AM Denis Garus <[hidden email]> wrote:
>
> > > Completing future from outside will never respect other subscribers
> that
> > > may expect other guatantees.
> >
> > For example, if we talk about public API like IgniteCache, what
> subscribers
> > may expect other guatantees?
> > IMHO, the best solution is to get the well-known standard interface to a
> > user, and he will be happy.
> >
> > But when we talk about internal classes like "exchange future" they could
> > be custom futures if convenient.
> >
> > вт, 30 мар. 2021 г. в 15:25, Atri Sharma <[hidden email]>:
> >
> > > IMO the only way Ignite should cancel computations is iff cancel method
> > is
> > > invoked, not implicitly if complete is invoked.
> > >
> > > On Tue, 30 Mar 2021 at 4:58 PM, Denis Garus <[hidden email]>
> wrote:
> > >
> > > > Hello!
> > > >
> > > > > Let's say a user started a compute with fut =
> compute.runAsync(task);
> > > > > and now calls fut.complete(someVal); Does this mean that Ignite no
> > > longer
> > > > needs to execute the task?
> > > > > If the task is currently running, does it need to be canceled?
> > > >
> > > > Yes, this case looks like Ignite should cancel computations because a
> > > user
> > > > wants to complete the future. Why not?
> > > > If there will be an opportunity to cancel a future, why is it a bad
> > > option
> > > > to finish a future through a complete() method?
> > > >
> > > > > If you look at Ignite-2 code, you may found a number of places
> where
> > we
> > > > return e.g. exchange futures or partition release futures.
> > > > > Assume the impact if we will return CompletableFuture instead,
> which
> > > can
> > > > be completed in 3-rd party plugin by mistake?
> > > >
> > > > If exchange futures or partition release futures can be returned to
> > 3-rd
> > > > party plugin by mistake, it is poor encapsulation.
> > > > And if it will be IgniteFuter rather than CompletedFuture, anyway,
> this
> > > can
> > > > harm.
> > > >
> > > > вт, 30 мар. 2021 г. в 13:14, Andrey Mashenkov <
> > > [hidden email]
> > > > >:
> > > >
> > > > > Guys,
> > > > >
> > > > > I want to remember there is one more point to pay attention to.
> > > > > Extending Future and CompletableStage is more than just prevents
> > > > unexpected
> > > > > behavior if a user completed the future.
> > > > >
> > > > > First of all, it helps us to write safer code as we won't a method
> > > > contract
> > > > > exposed such methods as to a user as to a developer.
> > > > > If you look at Ignite-2 code, you may found a number of places
> where
> > we
> > > > > return e.g. exchange futures or partition release futures.
> > > > > Assume the impact if we will return CompletableFuture instead,
> which
> > > can
> > > > be
> > > > > completed in 3-rd party plugin by mistake?
> > > > >
> > > > > The suggested approach allows us to don't bother if a
> > CompletableFuture
> > > > has
> > > > > to be wrapped or not.
> > > > >
> > > > >
> > > > > On Tue, Mar 30, 2021 at 12:22 PM Alexey Goncharuk <
> > > > > [hidden email]> wrote:
> > > > >
> > > > > > Ivan,
> > > > > >
> > > > > > My concern with the concept of a user completing the future
> > returned
> > > > from
> > > > > > Ignite public API is that it is unclear how to interpret this
> > action
> > > > > (this
> > > > > > backs Val's message).
> > > > > > Let's say a user started a compute with fut =
> > compute.runAsync(task);
> > > > and
> > > > > > now calls fut.complete(someVal); Does this mean that Ignite no
> > longer
> > > > > needs
> > > > > > to execute the task? If the task is currently running, does it
> need
> > > to
> > > > be
> > > > > > canceled?
> > > > > >
> > > > > > Using CompletableFuture.anyOf() is a good instrument in this case
> > > > because
> > > > > > it makes the 'first future wins' contract explicit in the code.
> > > Besides
> > > > > > that, the point regarding the cancel() method is valid, and we
> will
> > > > need
> > > > > > some custom mechanics to cancel a computation, so a custom
> > interface
> > > > that
> > > > > > simply extends both Future and CompletableStage seems reasonable
> to
> > > me.
> > > > > >
> > > > > > --AG
> > > > > >
> > > > > > пн, 29 мар. 2021 г. в 09:12, Ivan Pavlukhin <[hidden email]
> >:
> > > > > >
> > > > > > > Val,
> > > > > > >
> > > > > > > There were enough hype around Reactive programming past years.
> I
> > > > > > > remind a lot of talks about RxJava. And I suppose it worth to
> > > > consider
> > > > > > > it. But it requires some time to study modern trends to make a
> > > > choice.
> > > > > > > So far I am not ready to facilitate Reactive API for Ignite 3.
> > > > > > >
> > > > > > > Regarding CompletableFuture.
> > > > > > >
> > > > > > > > The point is that currently a future returned from any of
> > > Ignite's
> > > > > > async
> > > > > > > > operations is supposed to be completed with a value only by
> > > Ignite
> > > > > > > itself,
> > > > > > > > not by the user. If we follow the same approach in Ignite 3,
> > > > > returning
> > > > > > > > CompletableFuture is surely wrong in my view.
> > > > > > >
> > > > > > > My first thoughts was similar. But later I thought what a user
> > > would
> > > > > > > like do with returned future. And one of cases I imagined was a
> > > case
> > > > > > > of alternative result. E.g. a user uses Ignite and another data
> > > > source
> > > > > > > in his application. He wants to use a value arrived faster. He
> > > > > > > combines 2 futures like CompletableFuture.anyOf(...).
> > Consequently
> > > > > > > even if we prohibit CompletableFuture.complete(...) explicitly
> > then
> > > > it
> > > > > > > will be possible to create a combination that will allow
> > premature
> > > > > > > future completion. After all generally CompletableFuture is a
> > > > > > > placeholder for async computaion result and if a user wants to
> > > > > > > substitute result returned from Ignite why should we disallow
> him
> > > to
> > > > > > > do it?
> > > > > > >
> > > > > > > Also I found one more suspicious thing with CompletableFuture.
> As
> > > it
> > > > > > > is a concrete class it implements a cancel() method. And as I
> see
> > > the
> > > > > > > implementation does not try to cancel underlying computations.
> Is
> > > not
> > > > > > > it a problem?
> > > > > > >
> > > > > > > 2021-03-29 7:30 GMT+03:00, Valentin Kulichenko <
> > > > > > > [hidden email]>:
> > > > > > > > Ivan,
> > > > > > > >
> > > > > > > > It's not really about the "harm", but more about "what should
> > we
> > > do
> > > > > if
> > > > > > > this
> > > > > > > > method is called?". Imagine the following code:
> > > > > > > >
> > > > > > > > CompletableFuture<String> fut = cache.getAsync(key);
> > > > > > > > fut.complete("something");
> > > > > > > >
> > > > > > > > What should happen in this case?
> > > > > > > >
> > > > > > > > The point is that currently a future returned from any of
> > > Ignite's
> > > > > > async
> > > > > > > > operations is supposed to be completed with a value only by
> > > Ignite
> > > > > > > itself,
> > > > > > > > not by the user. If we follow the same approach in Ignite 3,
> > > > > returning
> > > > > > > > CompletableFuture is surely wrong in my view.
> > > > > > > >
> > > > > > > > At the same time, if we take a fundamentally different route
> > with
> > > > the
> > > > > > > async
> > > > > > > > APIs, this whole discussion might become irrelevant. For
> > example,
> > > > can
> > > > > > you
> > > > > > > > elaborate on your thinking around the reactive API? Do you
> have
> > > any
> > > > > > > > specifics in mind?
> > > > > > > >
> > > > > > > > -Val
> > > > > > > >
> > > > > > > > On Sat, Mar 27, 2021 at 9:18 PM Ivan Pavlukhin <
> > > > [hidden email]>
> > > > > > > wrote:
> > > > > > > >
> > > > > > > >> > The methods below shouldn't be accessible for user:
> > > > > > > >> > complete()
> > > > > > > >> > completeExceptionaly()
> > > > > > > >>
> > > > > > > >> Folks, in case of user-facing API, do you think there is a
> > real
> > > > harm
> > > > > > > >> in allowing a user to manually "complete" a future? I
> suppose
> > a
> > > > user
> > > > > > > >> employs some post-processing for future results and
> > potentially
> > > > > wants
> > > > > > > >> to have control of these results as well. E.g. premature
> > > > completion
> > > > > in
> > > > > > > >> case when a result is no longer needed is possible usage.
> > > > > > > >>
> > > > > > > >> Also I thinkg it might be a good time to ponder about
> > > > Future/Promise
> > > > > > > >> APIs in general. Why such API is our choice? Can we choose
> > e.g.
> > > > > > > >> Reactive API style instead?
> > > > > > > >>
> > > > > > > >> 2021-03-27 0:33 GMT+03:00, Valentin Kulichenko <
> > > > > > > >> [hidden email]>:
> > > > > > > >> > Andrey,
> > > > > > > >> >
> > > > > > > >> > I see. So in a nutshell, you're saying that we want to
> > return
> > > a
> > > > > > future
> > > > > > > >> that
> > > > > > > >> > the user's code is not allowed to complete. In this case,
> I
> > > > think
> > > > > > it's
> > > > > > > >> > clear that CompletableFuture is not what we need. We
> > actually
> > > > > need a
> > > > > > > >> > NonCompletableFuture :)
> > > > > > > >> >
> > > > > > > >> > My vote is for the custom interface.
> > > > > > > >> >
> > > > > > > >> > -Val
> > > > > > > >> >
> > > > > > > >> > On Fri, Mar 26, 2021 at 2:25 AM Andrey Mashenkov
> > > > > > > >> > <[hidden email]>
> > > > > > > >> > wrote:
> > > > > > > >> >
> > > > > > > >> >> Val,
> > > > > > > >> >>
> > > > > > > >> >> The methods below shouldn't be accessible for user:
> > > > > > > >> >> complete()
> > > > > > > >> >> completeExceptionaly()
> > > > > > > >> >>
> > > > > > > >> >> Returning CompletableFuture we must always make a copy to
> > > > prevent
> > > > > > the
> > > > > > > >> >> original future from being completed by mistake.
> > > > > > > >> >> I think it will NOT be enough to do that returing the
> > future
> > > to
> > > > > the
> > > > > > > >> >> end-user, but from every critical module to the outside
> of
> > > the
> > > > > > > module,
> > > > > > > >> >> e.g. to plugins. The impact of disclosing ExchangeFuture,
> > > > > > > >> >> PartitionReleaseFuture to plugins may be serious.
> > > > > > > >> >>
> > > > > > > >> >> IgniteFuture<T> extends Future<T>, CompletionStage<T>
> which
> > > > > > > >> >> implementation
> > > > > > > >> >> will just wrap CompletableFuture these issues will be
> > > resolved
> > > > in
> > > > > > > >> natural
> > > > > > > >> >> way.
> > > > > > > >> >> In addition we can force toCompletableFuture() method to
> > > > return a
> > > > > > > >> >> defensive
> > > > > > > >> >> copy(), that resolves the last concern.
> > > > > > > >> >>
> > > > > > > >> >>
> > > > > > > >> >> On Fri, Mar 26, 2021 at 11:38 AM Konstantin Orlov
> > > > > > > >> >> <[hidden email]>
> > > > > > > >> >> wrote:
> > > > > > > >> >>
> > > > > > > >> >> > CompletableFuture seems a better option to me.
> > > > > > > >> >> >
> > > > > > > >> >> > --
> > > > > > > >> >> > Regards,
> > > > > > > >> >> > Konstantin Orlov
> > > > > > > >> >> >
> > > > > > > >> >> >
> > > > > > > >> >> >
> > > > > > > >> >> >
> > > > > > > >> >> > > On 26 Mar 2021, at 11:07, Pavel Tupitsyn <
> > > > > [hidden email]
> > > > > > >
> > > > > > > >> >> > > wrote:
> > > > > > > >> >> > >
> > > > > > > >> >> > > On the one hand, I agree with Alexey.
> > > > > > > >> >> > > CompletableFuture has complete* methods which should
> > not
> > > be
> > > > > > > >> available
> > > > > > > >> >> to
> > > > > > > >> >> > > the user code.
> > > > > > > >> >> > > This can be solved with a simple interface like we do
> > in
> > > > Thin
> > > > > > > >> Client:
> > > > > > > >> >> > > IgniteClientFuture<T> extends Future<T>,
> > > CompletionStage<T>
> > > > > > > >> >> > >
> > > > > > > >> >> > >
> > > > > > > >> >> > > On the other hand:
> > > > > > > >> >> > > - CompletionStage has toCompletableFuture anyway
> > (rather
> > > > > weird)
> > > > > > > >> >> > > - Other libraries use CompletableFuture and it seems
> to
> > > be
> > > > > fine
> > > > > > > >> >> > > - Using CompletableFuture is the simplest approach
> > > > > > > >> >> > >
> > > > > > > >> >> > >
> > > > > > > >> >> > > So I lean towards CompletableFuture too.
> > > > > > > >> >> > >
> > > > > > > >> >> > > On Fri, Mar 26, 2021 at 10:46 AM Alexey Kukushkin <
> > > > > > > >> >> > [hidden email]>
> > > > > > > >> >> > > wrote:
> > > > > > > >> >> > >
> > > > > > > >> >> > >> I do not like Java's CompletableFuture and prefer
> our
> > > own
> > > > > > Future
> > > > > > > >> >> > (revised
> > > > > > > >> >> > >> IgniteFuture).
> > > > > > > >> >> > >>
> > > > > > > >> >> > >> My understanding of the Future (or Promise) pattern
> in
> > > > > general
> > > > > > > is
> > > > > > > >> >> having
> > > > > > > >> >> > >> two separate APIs:
> > > > > > > >> >> > >>
> > > > > > > >> >> > >>   1. Server-side: create, set result, raise error,
> > > cancel
> > > > > from
> > > > > > > >> >> > >> server.
> > > > > > > >> >> > >>   2. Client-side: get result, handle error, cancel
> > from
> > > > > client
> > > > > > > >> >> > >>
> > > > > > > >> >> > >> Java's CompletableFuture looks like both the
> > client-side
> > > > and
> > > > > > > >> >> > >> server-side API. The "Completeable" prefix in the
> name
> > > is
> > > > > > > already
> > > > > > > >> >> > confusing
> > > > > > > >> >> > >> for a client since it cannot "complete" an
> operation,
> > > > only a
> > > > > > > >> >> > >> server
> > > > > > > >> >> can.
> > > > > > > >> >> > >>
> > > > > > > >> >> > >> I would create our own IgniteFuture adding
> client-side
> > > > > > > >> functionality
> > > > > > > >> >> we
> > > > > > > >> >> > >> currently miss (like client-side cancellation).
> > > > > > > >> >> > >>
> > > > > > > >> >> > >>
> > > > > > > >> >> > >> пт, 26 мар. 2021 г. в 01:08, Valentin Kulichenko <
> > > > > > > >> >> > >> [hidden email]>:
> > > > > > > >> >> > >>
> > > > > > > >> >> > >>> Andrey,
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>> Can you compile a full list of these risky methods,
> > and
> > > > > > > >> >> > >>> elaborate
> > > > > > > >> >> > >>> on
> > > > > > > >> >> > what
> > > > > > > >> >> > >>> the risks are?
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>> Generally, CompletableFuture is a much better
> option,
> > > > > because
> > > > > > > >> >> > >>> it's
> > > > > > > >> >> > >>> standard. But we need to make sure it actually fits
> > our
> > > > > needs
> > > > > > > >> >> > >>> and
> > > > > > > >> >> > doesn't
> > > > > > > >> >> > >>> do more harm than good.
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>> -Val
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>> On Thu, Mar 25, 2021 at 12:23 PM Alexei Scherbakov
> <
> > > > > > > >> >> > >>> [hidden email]> wrote:
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>>> I think both options are fine, but personally lean
> > > > toward
> > > > > > > >> >> > >>>> CompletableFuture.
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>> чт, 25 мар. 2021 г. в 17:56, Atri Sharma <
> > > > [hidden email]
> > > > > >:
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>>> I would suggest using CompletableFuture -- I
> don't
> > > see
> > > > a
> > > > > > need
> > > > > > > >> for
> > > > > > > >> >> > >>>>> a
> > > > > > > >> >> > >>>> custom
> > > > > > > >> >> > >>>>> interface that is unique to us.
> > > > > > > >> >> > >>>>>
> > > > > > > >> >> > >>>>> It also allows a lower barrier for new
> contributors
> > > for
> > > > > > > >> >> understanding
> > > > > > > >> >> > >>>>> existing code
> > > > > > > >> >> > >>>>>
> > > > > > > >> >> > >>>>> On Thu, 25 Mar 2021, 20:18 Andrey Mashenkov, <
> > > > > > > >> >> > >>> [hidden email]
> > > > > > > >> >> > >>>>>
> > > > > > > >> >> > >>>>> wrote:
> > > > > > > >> >> > >>>>>
> > > > > > > >> >> > >>>>>> Hi Igniters,
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> I'd like to start a discussion about replacing
> our
> > > > > custom
> > > > > > > >> >> > >>> IgniteFuture
> > > > > > > >> >> > >>>>>> class with CompletableFuture - existed JDK class
> > > > > > > >> >> > >>>>>> or rework it's implementation (like some other
> > > > products
> > > > > > > done)
> > > > > > > >> to
> > > > > > > >> >> > >>>>>> a
> > > > > > > >> >> > >>>>>> composition of CompletionStage and Future
> > > interfaces.
> > > > > > > >> >> > >>>>>> or maybe other option if you have any ideas. Do
> > you?
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> 1. The first approach pros and cons are
> > > > > > > >> >> > >>>>>> + Well-known JDK class
> > > > > > > >> >> > >>>>>> + Already implemented
> > > > > > > >> >> > >>>>>> - It is a class, not an interface.
> > > > > > > >> >> > >>>>>> - Expose some potentially harmful methods like
> > > > > > "complete()".
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> On the other side, it has copy() method to
> create
> > > > > > defensive
> > > > > > > >> copy
> > > > > > > >> >> > >> and
> > > > > > > >> >> > >>>>>> minimalCompletionStage() to restrict harmful
> > method
> > > > > usage.
> > > > > > > >> >> > >>>>>> Thus, this look like an applicable solution, but
> > we
> > > > > should
> > > > > > > be
> > > > > > > >> >> > >> careful
> > > > > > > >> >> > >>>>>> exposing internal future to the outside.
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> 2. The second approach is to implement our own
> > > > interface
> > > > > > > like
> > > > > > > >> >> > >>>>>> the
> > > > > > > >> >> > >>> next
> > > > > > > >> >> > >>>>> one:
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> interface IgniteFuture<T> extends
> > > CompletableStage<T>,
> > > > > > > >> Future<T>
> > > > > > > >> >> > >>>>>> {
> > > > > > > >> >> > >>>>>> }
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> Pros and cons are
> > > > > > > >> >> > >>>>>> + Our interfaces/classes contracts will expose
> an
> > > > > > interface
> > > > > > > >> >> > >>>>>> rather
> > > > > > > >> >> > >>> than
> > > > > > > >> >> > >>>>>> concrete implementation.
> > > > > > > >> >> > >>>>>> + All methods are safe.
> > > > > > > >> >> > >>>>>> - Some implementation is required.
> > > > > > > >> >> > >>>>>> - CompletableStage has a method
> > > toCompletableFuture()
> > > > > and
> > > > > > > can
> > > > > > > >> be
> > > > > > > >> >> > >>>>> converted
> > > > > > > >> >> > >>>>>> to CompletableFuture. This should be supported.
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> However, we still could wrap CompletableFuture
> and
> > > > don't
> > > > > > > >> >> > >>>>>> bother
> > > > > > > >> >> > >> about
> > > > > > > >> >> > >>>>>> creating a defensive copy.
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> Other project experience:
> > > > > > > >> >> > >>>>>> * Spotify uses CompletableFuture directly [1].
> > > > > > > >> >> > >>>>>> * Redis goes the second approach [2]
> > > > > > > >> >> > >>>>>> * Vertx explicitly extends CompletableFuture
> [3].
> > > > > However,
> > > > > > > >> >> > >>>>>> they
> > > > > > > >> >> > >> have
> > > > > > > >> >> > >>>>> custom
> > > > > > > >> >> > >>>>>> future classes and a number of helpers that
> could
> > be
> > > > > > > replaced
> > > > > > > >> >> > >>>>>> with
> > > > > > > >> >> > >>>>>> CompletableStage. Maybe it is just a legacy.'
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> Any thoughts?
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>> [1]
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>
> > > > > > > >> >> >
> > > > > > > >> >>
> > > > > > > >>
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://spotify.github.io/completable-futures/apidocs/com/spotify/futures/ConcurrencyReducer.html
> > > > > > > >> >> > >>>>>> [2]
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>
> > > > > > > >> >> >
> > > > > > > >> >>
> > > > > > > >>
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://lettuce.io/lettuce-4/release/api/com/lambdaworks/redis/RedisFuture.html
> > > > > > > >> >> > >>>>>> [3]
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>
> > > > > > > >> >> >
> > > > > > > >> >>
> > > > > > > >>
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://javadoc.io/static/org.jspare.vertx/vertx-jspare/1.1.0-M03/org/jspare/vertx/concurrent/VertxCompletableFuture.html
> > > > > > > >> >> > >>>>>> --
> > > > > > > >> >> > >>>>>> Best regards,
> > > > > > > >> >> > >>>>>> Andrey V. Mashenkov
> > > > > > > >> >> > >>>>>>
> > > > > > > >> >> > >>>>>
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>> --
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>> Best regards,
> > > > > > > >> >> > >>>> Alexei Scherbakov
> > > > > > > >> >> > >>>>
> > > > > > > >> >> > >>>
> > > > > > > >> >> > >>
> > > > > > > >> >> > >>
> > > > > > > >> >> > >> --
> > > > > > > >> >> > >> Best regards,
> > > > > > > >> >> > >> Alexey
> > > > > > > >> >> > >>
> > > > > > > >> >> >
> > > > > > > >> >> >
> > > > > > > >> >>
> > > > > > > >> >> --
> > > > > > > >> >> Best regards,
> > > > > > > >> >> Andrey V. Mashenkov
> > > > > > > >> >>
> > > > > > > >> >
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> --
> > > > > > > >>
> > > > > > > >> Best regards,
> > > > > > > >> Ivan Pavlukhin
> > > > > > > >>
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > --
> > > > > > >
> > > > > > > Best regards,
> > > > > > > Ivan Pavlukhin
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Best regards,
> > > > > Andrey V. Mashenkov
> > > > >
> > > >
> > > --
> > > Regards,
> > >
> > > Atri
> > > Apache Concerted
> > >
> >
>