inmem snapshot store

[mr-git]

Currently there is a support for in-mem journal, but not for in-mem snapshot store.

https://github.com/alstanchev/pekko-persistence-inmemory provides such support, but as additional library.

Would it be possible to "integrate" the above-mentioned library next to org.apache.pekko.persistence.journal.inmem.InmemJournal?

[pjfanning]

1. I don't see why there can't be an ecosystem of Pekko community jars and why everything must become part of Apache Pekko
2. If we did agree to take this code over, we would need the code contributors to alstanchev/pekko-persistence-inmemory to agree to it and sign Apache CLAs and possibly also get a Software Grant signed.

[mr-git]

https://github.com/alstanchev/pekko-persistence-inmemory?tab=License-1-ov-file - they are using Apache License

[pjfanning]

I'm aware of that. ASF also require CLAs and SGAs.

[pjfanning]

It would be more complicated again if we did have to change the license too - all code contributors would need to agree to the license change.

[ptrdom]

PersistenceTestKitPlugin and PersistenceTestKitSnapshotPlugin exist in persistence-testkit module already, they provide in-memory storage for journal and snapshots, are they insufficient for your use case?

[mr-git]

honestly, I am not sure :(

in https://pekko.apache.org/docs/pekko/1.1/general/configuration-reference.html#config-pekko-persistence-testkit I cannot find the instruction on how to configure it - there is instruction only for InmemJournal usage

[ptrdom]

I guess persistence-testkit plugins were implemented after InmemJournal and what you need was not considered a user-facing part of the testkit plugins, hence no documentation. Maybe we should reconsider that.

Using the following configs should work:

pekko/persistence-testkit/src/main/scala/org/apache/pekko/persistence/testkit/PersistenceTestKitPlugin.scala

Lines 127 to 130 in f905240

	val config: Config = ConfigFactory.parseMap(
	Map(
	"pekko.persistence.journal.plugin" -> PluginId,
	s"$PluginId.class" -> s"${classOf[PersistenceTestKitPlugin].getName}").asJava)

pekko/persistence-testkit/src/main/scala/org/apache/pekko/persistence/testkit/PersistenceTestKitPlugin.scala

Lines 179 to 184 in f905240

	val config: Config = ConfigFactory.parseMap(
	Map(
	"pekko.persistence.snapshot-store.plugin" -> PluginId,
	s"$PluginId.class" -> classOf[PersistenceTestKitSnapshotPlugin].getName,
	s"$PluginId.snapshot-is-optional" -> false // fallback isn't used by the testkit
	).asJava)

[mr-git]

wow, got it working with extra config:

# In-memory snapshot-store plugin.
pekko.persistence.snapshot-store.inmem {
  # Class name of the plugin.
  class = "org.apache.pekko.persistence.testkit.PersistenceTestKitSnapshotPlugin"
}

so that I can use it in similar fashion as InmemJournal:

pekko .persistence {
  journal.plugin = "pekko.persistence.journal.inmem"
  snapshot-store.plugin = "pekko.persistence.snapshot-store.inmem"
}

IMHO, the first snippet mush be provided by testkit in same fashion as Journal's inmem is provided.

I guess it was like that in akka too, but current developer experience is sub-optimal