Configuring persistence plugins at runtime for EventSourcedBehavior

[ptrdom]

Resolves #1513.

[pjfanning]

there are quite a lot of changes to constructors - even if they are for internal classes

I don't know but we might want to consider adding secondary constructors that match the existing param lists in the 1.1.2-RC1 release.

[pjfanning]

private please

[ptrdom]

This is accessed in multiple places of EventSourcedBehavior state machine - ReplayingEvents and ReplayingSnapshot are using this to make error messages, so cannot be made private. Please advise if some different solution is required.

[pjfanning]

Can you add a @since 1.1.3 annotation to any new public classes, variables or functions?

[ptrdom]

Just double-checking - is this required for public members of classes marked with @InternalApi and private[pekko]?

[pjfanning]

I'm not sure - this whole PR is looking like something we might need to stick in a future major release as opposed to an upcoming patch release. Leave the since annotations out for now.

[ptrdom]

Understood. Is there any issue with creating a PR with this code in Akka repository? Wondering about any potential license conflicts, would not want interaction with BSL repositories voiding Pekko of this code.

[pjfanning]

Feel free to submit this to Akka. You own this code and submitting it Akka does not change that. The problem will only arise if you collaborate on some of the code with a Lightbend employee and then take that collaboration and try to submit that to us.

[pjfanning]

There are binary compat problems that will require adding an exclude file for.

[error] pekko-persistence-typed: Failed binary compatibility check against org.apache.pekko:pekko-persistence-typed_2.12:1.0.0! Found 2 potential problems
[error]  * abstract method withJournalPluginConfig(scala.Option)org.apache.pekko.persistence.typed.scaladsl.EventSourcedBehavior in interface org.apache.pekko.persistence.typed.scaladsl.EventSourcedBehavior is present only in current version
[error]    filter with: ProblemFilters.exclude[ReversedMissingMethodProblem]("org.apache.pekko.persistence.typed.scaladsl.EventSourcedBehavior.withJournalPluginConfig")
[error]  * abstract method withSnapshotPluginConfig(scala.Option)org.apache.pekko.persistence.typed.scaladsl.EventSourcedBehavior in interface org.apache.pekko.persistence.typed.scaladsl.EventSourcedBehavior is present only in current version
[error]    filter with: ProblemFilters.exclude[ReversedMissingMethodProblem]("org.apache.pekko.persistence.typed.scaladsl.EventSourcedBehavior.withSnapshotPluginConfig")
[error] java.lang.RuntimeException: Failed binary compatibility check against org.apache.pekko:pekko-persistence-typed_2.12:1.0.0! Found 2 potential problems

[pjfanning]

lgtm

[pjfanning]

I think the mima excludes are ok for a 1.1.3 release. I guess some other contributor might object but at this stage this has been open for a while. I'll merge but we can re-review if someone comes back with issues.

[pjfanning]

@raboof @mdedetrich do you think this causes issues for a 1.1.x release? I think Persistence APIs have been documented to be 'may change'. The bin compat issues in this PR do not appear to likely trouble anyone.

[raboof]

I can't find any reference to the type Persistence APIs being 'may change' - not in the code nor in the documentation.

However, since scaladsl.EventSourcedBehavior is marked @DoNotInherit, this change looks backwards compatible to me.

(we do encourage users inheriting from javadsl.EventSourcedBehavior, but that one has an implementation, so that's fine as well).