Support for native serializable types and/or exclusions about akka-serialization-helper

[gervaisb]

At least we do not have any errors at this time..
I was not aware of the SerializationTestKit, that's very good to know. I'm going to use it and update that issue accordingly.

I learnt about the plugin from Twitter: https://twitter.com/VirtusLab/status/1570312428218466306

[PawelLipski]

@gervaisb actually... work in progress ;) #304

[gervaisb]

Just upgraded to 0.7.0 everything is okay with the new parameter.

[PawelLipski]

Hmmm I'm not sure if these are truly false positives... do Either[_,_] and subclasses of scalapb.GeneratedMessage actually serialize successfully with Akka? 🤔 SerializationTestKit can be used to be make sure.

Btw out of curiosity, how did you learn of our plugin? ;)

[PawelLipski]

Ok! lmk how it goes and we'll think if/how to address

[gervaisb]

Hi there. Back with my "issue".

I do have this test that pass for a message with an Either.

// testKit: akka.actor.testkit.typed.scaladsl.ActorTestKit = ...
val probe = testKit.createTestProbe[Either[SampleError, SampleEvent]]()
val replyTo: ActorRef[Either[SampleError, SampleEvent]] = probe.ref

val subject = MessageWithEither(
    "Hello", replyTo
)
new SerializationTestKit(system)
    .verifySerialization(subject)

The system is configured with:

akka {
  actor {
    serializers {
      // ...
      jackson-cbor = "akka.serialization.jackson.JacksonCborSerializer"
    }
    serialization-bindings {
      // ...
      "scala.util.Either" = jackson-cbor
    }
  }
}

However, ASH report an error:

Either[org.acme.SampleError, org.acme.SampleEvent] is used as Akka message but does not extend a trait annotated with org.virtuslab.ash.annotation.SerializabilityTrait.
[error] Passing an object of a class that does NOT extend a trait annotated with org.virtuslab.ash.annotation.SerializabilityTrait as a message
[error] may cause Akka to fall back to Java serialization during runtime.
[error]
[error] replyTo: ActorRef[Either[SampleError, SampleEvent]]

You are right, Either[_,_] is not "natively serializable" with Akka. However, if I'm not mistaken, it should be in this case.

[PawelLipski]

Wow good to know 😯 Indeed, there should be a mechanism for marking certain types defined outside the user codebase as safe for serialization. There's a predefined list... but that's not configurable, alas ☹️

[gervaisb]

Okay, thanks.

We use Either on commands only. But we do have some snapshots that are not serializable. Is there any way to "exclude" our commands from your plugin, but keep all classes related to the states?

[PawelLipski]

Is there any way to "exclude" our commands from your plugin, but keep all classes related to the states?

Unfortunately, there's currently some configurability (https://github.com/VirtusLab/akka-serialization-helper/blob/main/docs/GUIDE.md#serializability-checker-compiler-plugin)... but that probably doesn't cover your case in any useful manner.

Just out of curiosity... would you be interested in providing a contribution to this repo? Ofc with review & all needed support on our side. We'll eventually be able to implement it ourselves as well (esp. given that there's an external interest in the project)... but it might take a longer while (as we're busy in unrelated projects that don't even use ASH) :///

[gervaisb]

Just out of curiosity... would you be interested in providing a contribution to this repo?

I'd love to. Unfortunately, I do not see much time on the coming months.

Thanks for the effort in #304 ! Awesome.

[PawelLipski]

Okay I've merged #304 and got a snapshot release ready... if @gervaisb you could:

1. set up access to snapshots as in the docs: https://github.com/VirtusLab/akka-serialization-helper/blob/main/CONTRIBUTING.md#snapshots
2. use the snapshot version 0.6.2+59-f4224184-SNAPSHOT (see Sonatype repo) instead of 0.6.2 you've got now (I suppose)
3. use the newly-added --types-explicitly-marked-as-serializable=... flag as in https://github.com/VirtusLab/akka-serialization-helper/blob/main/docs/GUIDE.md#serializability-checker-compiler-plugin

Once I get a good-to-go from you, I'm gonna release this version as v0.7.0 🚢

[gervaisb]

Awesome ! Thanks a lot.

Will try that ASAP.

[gervaisb]

Hello again. I just tested the last snapshot, and it seems to do the Job.

I have configured scala.util.Either and I am not bothered by this type any more but get "true" errors now. 👍

[PawelLipski]

Hello again. I just tested the last snapshot, and it seems to do the Job.

Gr8! 🎉 I'm running a release of v0.7.0 right now, once the packages make their way to Maven Central (which can take up to 12 hrs), you can replace the snapshot version with 0.7.0.

However, we do have errors for generic types

Hmm this error is probably expected, as there's no guarantee that E will serialize in runtime indeed... would it make sense to provide a lower bound for these types, like abstract class Projection[Event <: MySerializable]?

Otherwise, you can take a look at --disable-detection-generics compiler plugin option (https://github.com/VirtusLab/akka-serialization-helper/blob/main/docs/GUIDE.md#serializability-checker-compiler-plugin)