Clarify on policy/licensing questions for (new) stream operators

[kstokoz]

Hi,

I have a question regarding adding/mirroring operators that are available in Akka streams in Pekko, i.e.

Source/Flow.mapAsyncPartitioned
Source/Flow.mapWithResource
Flow.contramap

It is allowed to add such to pekko? Are there any policies around mirroring functionality?

Regards,
Kyrylo

[pjfanning]

Apache Pekko is a fork of Akka 2.6.20. Every API that is in Akka 2.6.20 is in Pekko. If these have been newly added to Akka 2.7 or 2.8, then we can look at adding them to Pekko but we can't copy the new Akka code. Any Akka code added since 2.7.0 is licensed under a new license that is not Apache Software License compatible.

[kstokoz]

These operators were added after the fork, mapAsynPartitioned was added in 2.8 (redacted link).
How in this case it can be added to Pekko?

[jaceksokol]

Hi, I can create a PR with the operator, but I can't promise I will do this this week. But you're free to re-use the code.

[He-Pin]

@jaceksokol refs: #561 , welcome:), on your ride.

[pjfanning]

Thanks @jaceksokol - I have already created #561. If you could review it that would be great. Or if you prefer to create a PR of your own, we can go that route too.

[jaceksokol]

The PR looks fine, the only thing is to review the licence files, but I'm not an expert to do this 😉

[He-Pin]

Maybe you can resend the PR and let's @pjfanning as a coauther, then the license is not need.

[He-Pin]

@kstokoz I can port my two operators, but still a little busy at $work, But the mapAsyncPartitioned I don't have the copyright, so I can't, I don't know whether we can just implemented the API.

[pjfanning]

Please, no rush. This is useful but not worth sweating on. Any time that you have free time but do it when it suits you.

[pjfanning]

You can read the Akka issue for mapAsyncPartitioned but it best not to look at the PR. Any docs are ok too. I'm not sure about reading discussion on the PR but we shouldn't read the code - it just seems safest to stay away from the PR.

[mdedetrich]

Document/examples yes, code absolutely not.

If you implement a mirror of mapAsyncPartitioned, your also allowed to compare the results of your implementation versus Akka's (i.e. pass inputs into your mapAsyncPartitioned, take notes of the outputs and compare that to the inputs passed into Akka's mapAsyncPartitioned).

But again do not look at the source code of Akka when doing this, just "run" the Akka binaries (i.e. jar's).

[He-Pin]

the mapAsyncPatition is difficulty to get right, I will put it aside for now，and thanks for the clarification.

[mdedetrich]

It would be nice to have these functions at some point if we can implement it but its definitely not urgent.

[He-Pin]

@kstokoz contramap has been added, if you want anyother operators, please comment in #605 and let's get adequate votes.

[He-Pin]

@kstokoz #931 add mapWithResource operator.