fix #23618 : Support for persistence dynamic configuration at runtime (#23841)

akka-docs/src/main/paradox/persistence.md

@@ -1434,3 +1434,17 @@ Note that `journalPluginId` and `snapshotPluginId` must refer to properly config
 plugin entries with a standard `class` property as well as settings which are specific for those plugins, i.e.:
 
 @@snip [PersistenceMultiDocSpec.scala]($code$/scala/docs/persistence/PersistenceMultiDocSpec.scala) { #override-config }
+
+## Give persistence plugin configurations at runtime
+
+By default, a persistent actor will use the configuration loaded at `ActorSystem` creation time to create journal and snapshot store plugins.
+
+When the persistent actor overrides the `journalPluginConfig` and `snapshotPluginConfig` methods,
+the actor will use the declared `Config` objects with a fallback on the default configuration.
+It allows a dynamic configuration of the journal and the snapshot store at runtime:
+
+Scala
+:  @@snip [PersistenceMultiDocSpec.scala]($code$/scala/docs/persistence/PersistenceMultiDocSpec.scala) { #runtime-config }
+
+Java
+:  @@snip [PersistenceMultiDocTest.java]($code$/java/jdocs/persistence/PersistenceMultiDocTest.java) { #runtime-config }

akka-docs/src/test/java/jdocs/persistence/PersistenceMultiDocTest.java

@@ -4,28 +4,85 @@
 
 package jdocs.persistence;
 
+import akka.persistence.AbstractPersistentActor;
+import akka.persistence.RuntimePluginConfig;
 import akka.persistence.UntypedPersistentActor;
+import com.typesafe.config.Config;
+import com.typesafe.config.ConfigFactory;
 
 public class PersistenceMultiDocTest {
 
     //#default-plugins
-    abstract class ActorWithDefaultPlugins extends UntypedPersistentActor {
+    abstract class AbstractPersistentActorWithDefaultPlugins extends AbstractPersistentActor {
         @Override
-        public String persistenceId() { return "123"; }
+        public String persistenceId() {
+            return "123";
+        }
     }
     //#default-plugins
 
     //#override-plugins
-    abstract class ActorWithOverridePlugins extends UntypedPersistentActor {
+    abstract class AbstractPersistentActorWithOverridePlugins extends AbstractPersistentActor {
         @Override
-        public String persistenceId() { return "123"; }
+        public String persistenceId() {
+            return "123";
+        }
+
         // Absolute path to the journal plugin configuration entry in the `reference.conf`
         @Override
-        public String journalPluginId() { return "akka.persistence.chronicle.journal"; }
+        public String journalPluginId() {
+            return "akka.persistence.chronicle.journal";
+        }
+
         // Absolute path to the snapshot store plugin configuration entry in the `reference.conf`
         @Override
-        public String snapshotPluginId() { return "akka.persistence.chronicle.snapshot-store"; }
+        public String snapshotPluginId() {
+            return "akka.persistence.chronicle.snapshot-store";
+        }
     }
     //#override-plugins
 
+    //#runtime-config
+    abstract class AbstractPersistentActorWithRuntimePluginConfig extends AbstractPersistentActor implements RuntimePluginConfig {
+        // Variable that is retrieved at runtime, from an external service for instance.
+        String runtimeDistinction = "foo";
+
+        @Override
+        public String persistenceId() {
+            return "123";
+        }
+
+        // Absolute path to the journal plugin configuration entry in the `reference.conf`
+        @Override
+        public String journalPluginId() {
+            return "journal-plugin-" + runtimeDistinction;
+        }
+
+        // Absolute path to the snapshot store plugin configuration entry in the `reference.conf`
+        @Override
+        public String snapshotPluginId() {
+            return "snapshot-store-plugin-" + runtimeDistinction;
+        }
+
+        // Configuration which contains the journal plugin id defined above
+        @Override
+        public Config journalPluginConfig() {
+            return ConfigFactory.empty().withValue(
+                    "journal-plugin-" + runtimeDistinction,
+                    getContext().getSystem().settings().config().getValue("journal-plugin") // or a very different configuration coming from an external service.
+            );
+        }
+
+        // Configuration which contains the snapshot store plugin id defined above
+        @Override
+        public Config snapshotPluginConfig() {
+            return ConfigFactory.empty().withValue(
+                    "snapshot-plugin-" + runtimeDistinction,
+                    getContext().getSystem().settings().config().getValue("snapshot-store-plugin") // or a very different configuration coming from an external service.
+            );
+        }
+
+    }
+    //#runtime-config
+
 }

akka-docs/src/test/java/jdocs/persistence/PersistenceQueryDocTest.java

@@ -20,6 +20,7 @@ import akka.stream.javadsl.Sink;
 import akka.stream.javadsl.Source;
 import akka.util.Timeout;
 
+import com.typesafe.config.ConfigFactory;
 import docs.persistence.query.MyEventsByTagPublisher;
 import org.reactivestreams.Subscriber;
 import scala.concurrent.duration.FiniteDuration;

akka-docs/src/test/scala/docs/persistence/PersistenceMultiDocSpec.scala

@@ -2,11 +2,13 @@
  * Copyright (C) 2009-2018 Lightbend Inc. <https://www.lightbend.com>
  */
 
-import akka.persistence.PersistentActor
+import akka.persistence.{ RuntimePluginConfig, PersistentActor }
+import com.typesafe.config.ConfigFactory
 
 object PersistenceMultiDocSpec {
 
-  val DefaultConfig = """
+  val DefaultConfig =
+    """
   //#default-config
   # Absolute path to the default journal plugin configuration entry.
   akka.persistence.journal.plugin = "akka.persistence.journal.inmem"
@@ -19,9 +21,11 @@ object PersistenceMultiDocSpec {
   trait ActorWithDefaultPlugins extends PersistentActor {
     override def persistenceId = "123"
   }
+
   //#default-plugins
 
-  val OverrideConfig = s"""
+  val OverrideConfig =
+    s"""
   //#override-config
   # Configuration entry for the custom journal plugin, see `journalPluginId`.
   akka.persistence.chronicle.journal {
@@ -43,11 +47,42 @@ object PersistenceMultiDocSpec {
   //#override-plugins
   trait ActorWithOverridePlugins extends PersistentActor {
     override def persistenceId = "123"
+
     // Absolute path to the journal plugin configuration entry in the `reference.conf`.
     override def journalPluginId = "akka.persistence.chronicle.journal"
+
     // Absolute path to the snapshot store plugin configuration entry in the `reference.conf`.
     override def snapshotPluginId = "akka.persistence.chronicle.snapshot-store"
   }
+
   //#override-plugins
 
+  //#runtime-config
+  trait ActorWithRuntimePluginConfig extends PersistentActor with RuntimePluginConfig {
+    // Variable that is retrieved at runtime, from an external service for instance.
+    val runtimeDistinction = "foo"
+
+    override def persistenceId = "123"
+
+    // Absolute path to the journal plugin configuration entry, not defined in the `reference.conf`.
+    override def journalPluginId = s"journal-plugin-$runtimeDistinction"
+
+    // Absolute path to the snapshot store plugin configuration entry, not defined in the `reference.conf`.
+    override def snapshotPluginId = s"snapshot-store-plugin-$runtimeDistinction"
+
+    // Configuration which contains the journal plugin id defined above
+    override def journalPluginConfig = ConfigFactory.empty().withValue(
+      s"journal-plugin-$runtimeDistinction",
+      context.system.settings.config.getValue("journal-plugin") // or a very different configuration coming from an external service.
+    )
+
+    // Configuration which contains the snapshot store plugin id defined above
+    override def snapshotPluginConfig = ConfigFactory.empty().withValue(
+      s"snapshot-plugin-$runtimeDistinction",
+      context.system.settings.config.getValue("snapshot-store-plugin") // or a very different configuration coming from an external service.
+    )
+
+  }
+
+  //#runtime-config
 }

akka-persistence-query/src/main/scala/akka/persistence/query/PersistenceQuery.scala

@@ -5,11 +5,13 @@
 package akka.persistence.query
 
 import java.util.concurrent.atomic.AtomicReference
+
 import akka.actor._
 import akka.event.Logging
+
 import scala.annotation.tailrec
 import scala.util.Failure
-import com.typesafe.config.Config
+import com.typesafe.config.{ Config, ConfigFactory }
 
 /**
  * Persistence extension for queries.
@@ -39,21 +41,33 @@ class PersistenceQuery(system: ExtendedActorSystem) extends Extension {
   /** Discovered query plugins. */
   private val readJournalPluginExtensionIds = new AtomicReference[Map[String, ExtensionId[PluginHolder]]](Map.empty)
 
+  /**
+   * Scala API: Returns the [[akka.persistence.query.scaladsl.ReadJournal]] specified by the given
+   * read journal configuration entry.
+   *
+   * The provided readJournalPluginConfig will be used to configure the journal plugin instead of the actor system
+   * config.
+   */
+  final def readJournalFor[T <: scaladsl.ReadJournal](readJournalPluginId: String, readJournalPluginConfig: Config): T =
+    readJournalPluginFor(readJournalPluginId, readJournalPluginConfig).scaladslPlugin.asInstanceOf[T]
+
   /**
    * Scala API: Returns the [[akka.persistence.query.scaladsl.ReadJournal]] specified by the given
    * read journal configuration entry.
    */
   final def readJournalFor[T <: scaladsl.ReadJournal](readJournalPluginId: String): T =
-    readJournalPluginFor(readJournalPluginId).scaladslPlugin.asInstanceOf[T]
+    readJournalFor(readJournalPluginId, ConfigFactory.empty)
 
   /**
    * Java API: Returns the [[akka.persistence.query.javadsl.ReadJournal]] specified by the given
    * read journal configuration entry.
    */
-  final def getReadJournalFor[T <: javadsl.ReadJournal](clazz: Class[T], readJournalPluginId: String): T =
+  final def getReadJournalFor[T <: javadsl.ReadJournal](clazz: Class[T], readJournalPluginId: String, readJournalPluginConfig: Config): T =
-    readJournalPluginFor(readJournalPluginId).javadslPlugin.asInstanceOf[T]
+    readJournalPluginFor(readJournalPluginId, readJournalPluginConfig).javadslPlugin.asInstanceOf[T]
 
-  @tailrec private def readJournalPluginFor(readJournalPluginId: String): PluginHolder = {
+  final def getReadJournalFor[T <: javadsl.ReadJournal](clazz: Class[T], readJournalPluginId: String): T = getReadJournalFor[T](clazz, readJournalPluginId, ConfigFactory.empty())
+
+  @tailrec private def readJournalPluginFor(readJournalPluginId: String, readJournalPluginConfig: Config): PluginHolder = {
     val configPath = readJournalPluginId
     val extensionIdMap = readJournalPluginExtensionIds.get
     extensionIdMap.get(configPath) match {
@@ -62,20 +76,21 @@ class PersistenceQuery(system: ExtendedActorSystem) extends Extension {
       case None ⇒
         val extensionId = new ExtensionId[PluginHolder] {
           override def createExtension(system: ExtendedActorSystem): PluginHolder = {
-            val provider = createPlugin(configPath)
+            val provider = createPlugin(configPath, readJournalPluginConfig)
             PluginHolder(provider.scaladslReadJournal(), provider.javadslReadJournal())
           }
         }
         readJournalPluginExtensionIds.compareAndSet(extensionIdMap, extensionIdMap.updated(configPath, extensionId))
-        readJournalPluginFor(readJournalPluginId) // Recursive invocation.
+        readJournalPluginFor(readJournalPluginId, readJournalPluginConfig) // Recursive invocation.
     }
   }
 
-  private def createPlugin(configPath: String): ReadJournalProvider = {
+  private def createPlugin(configPath: String, readJournalPluginConfig: Config): ReadJournalProvider = {
+    val mergedConfig = readJournalPluginConfig.withFallback(system.settings.config)
     require(
-      !isEmpty(configPath) && system.settings.config.hasPath(configPath),
+      !isEmpty(configPath) && mergedConfig.hasPath(configPath),
       s"'reference.conf' is missing persistence read journal plugin config path: '${configPath}'")
-    val pluginConfig = system.settings.config.getConfig(configPath)
+    val pluginConfig = mergedConfig.getConfig(configPath)
     val pluginClassName = pluginConfig.getString("class")
     log.debug(s"Create plugin: ${configPath} ${pluginClassName}")
     val pluginClass = system.dynamicAccess.getClassFor[AnyRef](pluginClassName).get

akka-persistence-query/src/test/java/akka/persistence/query/PersistenceQueryTest.java

@@ -7,6 +7,7 @@ package akka.persistence.query;
 import akka.NotUsed;
 import akka.actor.ActorSystem;
 import akka.testkit.AkkaJUnitActorSystemResource;
+import com.typesafe.config.ConfigFactory;
 import org.junit.ClassRule;
 
 

akka-persistence-query/src/test/scala/akka/persistence/query/DummyReadJournal.scala

@@ -13,7 +13,7 @@ import akka.actor.ExtendedActorSystem
  * Use for tests only!
  * Emits infinite stream of strings (representing queried for events).
  */
-class DummyReadJournal extends scaladsl.ReadJournal with scaladsl.PersistenceIdsQuery {
+class DummyReadJournal(val dummyValue: String) extends scaladsl.ReadJournal with scaladsl.PersistenceIdsQuery {
   override def persistenceIds(): Source[String, NotUsed] =
     Source.fromIterator(() ⇒ Iterator.from(0)).map(_.toString)
 }
@@ -42,13 +42,19 @@ object DummyReadJournalProvider {
       ${DummyReadJournal.Identifier}4 {
         class = "${classOf[DummyReadJournalProvider4].getCanonicalName}"
       }
+      ${DummyReadJournal.Identifier}5 {
+        class = "${classOf[DummyReadJournalProvider5].getCanonicalName}"
+      }
     """)
 }
 
-class DummyReadJournalProvider extends ReadJournalProvider {
+class DummyReadJournalProvider(dummyValue: String) extends ReadJournalProvider {
+
+  // mandatory zero-arg constructor
+  def this() = this("dummy")
 
   override val scaladslReadJournal: DummyReadJournal =
-    new DummyReadJournal
+    new DummyReadJournal(dummyValue)
 
   override val javadslReadJournal: DummyReadJournalForJava =
     new DummyReadJournalForJava(scaladslReadJournal)
@@ -60,3 +66,7 @@ class DummyReadJournalProvider3(sys: ExtendedActorSystem, conf: Config) extends
 
 class DummyReadJournalProvider4(sys: ExtendedActorSystem, conf: Config, confPath: String) extends DummyReadJournalProvider
 
+class DummyReadJournalProvider5(sys: ExtendedActorSystem) extends DummyReadJournalProvider
+
+class CustomDummyReadJournalProvider5(sys: ExtendedActorSystem) extends DummyReadJournalProvider("custom")
+

akka-persistence-query/src/test/scala/akka/persistence/query/PersistenceQuerySpec.scala

@@ -5,11 +5,12 @@
 package akka.persistence.query
 
 import java.util.concurrent.atomic.AtomicInteger
+
 import akka.actor.ActorSystem
-import akka.persistence.journal.EventSeq
+import akka.persistence.journal.{ EventSeq, ReadEventAdapter }
-import akka.persistence.journal.ReadEventAdapter
+import com.typesafe.config.{ Config, ConfigFactory }
-import com.typesafe.config.ConfigFactory
 import org.scalatest.{ BeforeAndAfterAll, Matchers, WordSpecLike }
+
 import scala.concurrent.Await
 import scala.concurrent.duration._
 
@@ -24,14 +25,38 @@ class PersistenceQuerySpec extends WordSpecLike with Matchers with BeforeAndAfte
        |}
     """.stripMargin
 
+  val customReadJournalPluginConfig =
+    s"""
+       |${DummyReadJournal.Identifier}5 {
+       |  class = "${classOf[CustomDummyReadJournalProvider5].getCanonicalName}"
+       |}
+       |${DummyReadJournal.Identifier}6 {
+       |  class = "${classOf[DummyReadJournalProvider].getCanonicalName}"
+       |}
+     """.stripMargin
+
   "ReadJournal" must {
     "be found by full config key" in {
       withActorSystem() { system ⇒
-        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](DummyReadJournal.Identifier)
+        val readJournalPluginConfig: Config = ConfigFactory.parseString(customReadJournalPluginConfig)
+        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](
+          DummyReadJournal.Identifier, readJournalPluginConfig)
         // other combinations of constructor parameters
-        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](DummyReadJournal.Identifier + "2")
+        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](
-        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](DummyReadJournal.Identifier + "3")
+          DummyReadJournal.Identifier + "2", readJournalPluginConfig)
-        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](DummyReadJournal.Identifier + "4")
+        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](
+          DummyReadJournal.Identifier + "3", readJournalPluginConfig)
+        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](
+          DummyReadJournal.Identifier + "4", readJournalPluginConfig)
+        // config key existing within both the provided readJournalPluginConfig
+        // and the actorSystem config. The journal must be created from the provided config then.
+        val dummyReadJournal5 = PersistenceQuery.get(system).readJournalFor[DummyReadJournal](
+          DummyReadJournal.Identifier + "5", readJournalPluginConfig)
+        dummyReadJournal5.dummyValue should equal("custom")
+        // config key directly coming from the provided readJournalPluginConfig,
+        // and does not exist within the actorSystem config
+        PersistenceQuery.get(system).readJournalFor[DummyReadJournal](
+          DummyReadJournal.Identifier + "6", readJournalPluginConfig)
       }
     }
 
@@ -46,6 +71,7 @@ class PersistenceQuerySpec extends WordSpecLike with Matchers with BeforeAndAfte
   }
 
   private val systemCounter = new AtomicInteger()
+
   private def withActorSystem(conf: String = "")(block: ActorSystem ⇒ Unit): Unit = {
     val config =
       DummyReadJournalProvider.config
@@ -60,8 +86,13 @@ class PersistenceQuerySpec extends WordSpecLike with Matchers with BeforeAndAfte
 }
 
 object ExampleQueryModels {
-  case class OldModel(value: String) { def promote = NewModel(value) }
+
+  case class OldModel(value: String) {
+    def promote = NewModel(value)
+  }
+
   case class NewModel(value: String)
+
 }
 
 class PrefixStringWithPAdapter extends ReadEventAdapter {

akka-persistence-query/src/test/scala/akka/persistence/query/journal/leveldb/EventsByPersistenceIdSpec.scala

@@ -60,7 +60,7 @@ class EventsByPersistenceIdSpec extends AkkaSpec(EventsByPersistenceIdSpec.confi
       src.map(_.event).runWith(TestSink.probe[Any])
         .request(2)
         .expectNext("a-1", "a-2")
-        .expectNoMsg(500.millis)
+        .expectNoMessage(500.millis)
         .request(2)
         .expectNext("a-3")
         .expectComplete()
@@ -81,13 +81,13 @@ class EventsByPersistenceIdSpec extends AkkaSpec(EventsByPersistenceIdSpec.confi
       val probe = src.map(_.event).runWith(TestSink.probe[Any])
         .request(2)
         .expectNext("f-1", "f-2")
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
 
       ref ! "f-4"
       expectMsg("f-4-done")
 
       probe
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
         .request(5)
         .expectNext("f-3")
         .expectComplete() // f-4 not seen
@@ -186,13 +186,13 @@ class EventsByPersistenceIdSpec extends AkkaSpec(EventsByPersistenceIdSpec.confi
       val probe = src.map(_.event).runWith(TestSink.probe[Any])
         .request(2)
         .expectNext("e-1", "e-2")
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
 
       ref ! "e-4"
       expectMsg("e-4-done")
 
       probe
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
         .request(5)
         .expectNext("e-3")
         .expectNext("e-4")

akka-persistence-query/src/test/scala/akka/persistence/query/journal/leveldb/EventsByTagSpec.scala

@@ -79,7 +79,7 @@ class EventsByTagSpec extends AkkaSpec(EventsByTagSpec.config)
         .request(2)
         .expectNext(EventEnvelope(Sequence(1L), "a", 2L, "a green apple"))
         .expectNext(EventEnvelope(Sequence(2L), "a", 3L, "a green banana"))
-        .expectNoMsg(500.millis)
+        .expectNoMessage(500.millis)
         .request(2)
         .expectNext(EventEnvelope(Sequence(3L), "b", 2L, "a green leaf"))
         .expectComplete()
@@ -99,13 +99,13 @@ class EventsByTagSpec extends AkkaSpec(EventsByTagSpec.config)
         .request(2)
         .expectNext(EventEnvelope(Sequence(1L), "a", 2L, "a green apple"))
         .expectNext(EventEnvelope(Sequence(2L), "a", 3L, "a green banana"))
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
 
       c ! "a green cucumber"
       expectMsg(s"a green cucumber-done")
 
       probe
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
         .request(5)
         .expectNext(EventEnvelope(Sequence(3L), "b", 2L, "a green leaf"))
         .expectComplete() // green cucumber not seen
@@ -130,7 +130,7 @@ class EventsByTagSpec extends AkkaSpec(EventsByTagSpec.config)
       val probe = blackSrc.runWith(TestSink.probe[Any])
         .request(2)
         .expectNext(EventEnvelope(Sequence(1L), "b", 1L, "a black car"))
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
 
       d ! "a black dog"
       expectMsg(s"a black dog-done")
@@ -139,7 +139,7 @@ class EventsByTagSpec extends AkkaSpec(EventsByTagSpec.config)
 
       probe
         .expectNext(EventEnvelope(Sequence(2L), "d", 1L, "a black dog"))
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
         .request(10)
         .expectNext(EventEnvelope(Sequence(3L), "d", 2L, "a black night"))
     }
@@ -151,7 +151,7 @@ class EventsByTagSpec extends AkkaSpec(EventsByTagSpec.config)
         // note that banana is not included, since exclusive offset
         .expectNext(EventEnvelope(Sequence(3L), "b", 2L, "a green leaf"))
         .expectNext(EventEnvelope(Sequence(4L), "c", 1L, "a green cucumber"))
-        .expectNoMsg(100.millis)
+        .expectNoMessage(100.millis)
     }
 
   }

akka-persistence/src/main/mima-filters/2.5.11.backwards.excludes

@@ -1,4 +1,10 @@
+# #23841 Remove backward compatibility on some akka-persistence internal API
+ProblemFilters.exclude[DirectMissingMethodProblem]("akka.persistence.Persistence.journalConfigFor")
+ProblemFilters.exclude[DirectMissingMethodProblem]("akka.persistence.Persistence.journalFor")
+ProblemFilters.exclude[DirectMissingMethodProblem]("akka.persistence.Persistence.snapshotStoreFor")
+
 # #24508 Adding defer method to PersistentActor
 ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.persistence.PersistentActor.defer")
 ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.persistence.Eventsourced.internalDefer")
 ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.persistence.AbstractPersistentActorLike.defer")
+

akka-persistence/src/main/scala/akka/persistence/Eventsourced.scala

@@ -12,6 +12,7 @@ import akka.annotation.InternalApi
 import akka.dispatch.Envelope
 import akka.event.{ Logging, LoggingAdapter }
 import akka.util.Helpers.ConfigOps
+import com.typesafe.config.ConfigFactory
 
 import scala.collection.immutable
 import scala.concurrent.duration.FiniteDuration
@@ -26,8 +27,10 @@ private[persistence] object Eventsourced {
   /** INTERNAL API */
   private[akka] sealed trait PendingHandlerInvocation {
     def evt: Any
+
     def handler: Any ⇒ Unit
   }
+
   /** INTERNAL API: forces actor to stash incoming commands until all these invocations are handled */
   private[akka] final case class StashingHandlerInvocation(evt: Any, handler: Any ⇒ Unit) extends PendingHandlerInvocation
   /** INTERNAL API: does not force the actor to stash commands; Originates from either `persistAsync` or `defer` calls */
@@ -58,15 +61,34 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
 
   private val extension = Persistence(context.system)
 
-  private[persistence] lazy val journal = extension.journalFor(journalPluginId)
+  private[persistence] lazy val journal = {
-  private[persistence] lazy val snapshotStore = extension.snapshotStoreFor(snapshotPluginId)
+    val journalPluginConfig = this match {
+      case c: RuntimePluginConfig ⇒ c.journalPluginConfig
+      case _                      ⇒ ConfigFactory.empty
+    }
+    extension.journalFor(journalPluginId, journalPluginConfig)
+  }
+
+  private[persistence] lazy val snapshotStore = {
+    val snapshotPluginConfig = this match {
+      case c: RuntimePluginConfig ⇒ c.snapshotPluginConfig
+      case _                      ⇒ ConfigFactory.empty
+    }
+    extension.snapshotStoreFor(snapshotPluginId, snapshotPluginConfig)
+  }
 
   private val instanceId: Int = Eventsourced.instanceIdCounter.getAndIncrement()
   private val writerUuid = UUID.randomUUID.toString
 
   private var journalBatch = Vector.empty[PersistentEnvelope]
   // no longer used, but kept for binary compatibility
-  private val maxMessageBatchSize = extension.journalConfigFor(journalPluginId).getInt("max-message-batch-size")
+  private val maxMessageBatchSize = {
+    val journalPluginConfig = this match {
+      case c: RuntimePluginConfig ⇒ c.journalPluginConfig
+      case _                      ⇒ ConfigFactory.empty
+    }
+    extension.journalConfigFor(journalPluginId, journalPluginConfig).getInt("max-message-batch-size")
+  }
   private var writeInProgress = false
   private var sequenceNr: Long = 0L
   private var _lastSequenceNr: Long = 0L
@@ -77,7 +99,8 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
   // Used instead of iterating `pendingInvocations` in order to check if safe to revert to processing commands
   private var pendingStashingPersistInvocations: Long = 0
   // Holds user-supplied callbacks for persist/persistAsync calls
-  private val pendingInvocations = new java.util.LinkedList[PendingHandlerInvocation]() // we only append / isEmpty / get(0) on it
+  private val pendingInvocations = new java.util.LinkedList[PendingHandlerInvocation]()
+  // we only append / isEmpty / get(0) on it
   private var eventBatch: List[PersistentEnvelope] = Nil
 
   private val internalStash = createStash()
@@ -183,7 +206,14 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
     if (all) internalStash.unstashAll() else internalStash.unstash()
 
   private def startRecovery(recovery: Recovery): Unit = {
-    changeState(recoveryStarted(recovery.replayMax))
+    val timeout = {
+      val journalPluginConfig = this match {
+        case c: RuntimePluginConfig ⇒ c.journalPluginConfig
+        case _                      ⇒ ConfigFactory.empty
+      }
+      extension.journalConfigFor(journalPluginId, journalPluginConfig).getMillisDuration("recovery-event-timeout")
+    }
+    changeState(recoveryStarted(recovery.replayMax, timeout))
     loadSnapshot(snapshotterId, recovery.fromSnapshot, recovery.toSequenceNr)
   }
 
@@ -197,7 +227,8 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
     require(persistenceId.trim.nonEmpty, s"persistenceId cannot be empty for PersistentActor [${self.path}]")
 
     // Fail fast on missing plugins.
-    val j = journal; val s = snapshotStore
+    val j = journal;
+    val s = snapshotStore
     requestRecoveryPermit()
     super.aroundPreStart()
   }
@@ -431,6 +462,7 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
 
   private trait State {
     def stateReceive(receive: Receive, message: Any): Unit
+
     def recoveryRunning: Boolean
   }
 
@@ -445,6 +477,7 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
   private def waitingRecoveryPermit(recovery: Recovery) = new State {
 
     override def toString: String = s"waiting for recovery permit"
+
     override def recoveryRunning: Boolean = true
 
     override def stateReceive(receive: Receive, message: Any) = message match {
@@ -463,11 +496,10 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
    * All incoming messages are stashed.
    *
    * @param replayMax maximum number of messages to replay.
+   * @param timeout recovery event timeout
    */
-  private def recoveryStarted(replayMax: Long) = new State {
+  private def recoveryStarted(replayMax: Long, timeout: FiniteDuration) = new State {
 
-    // protect against snapshot stalling forever because of journal overloaded and such
-    val timeout = extension.journalConfigFor(journalPluginId).getMillisDuration("recovery-event-timeout")
     val timeoutCancellable = {
       import context.dispatcher
       context.system.scheduler.scheduleOnce(timeout, self, RecoveryTick(snapshot = true))
@@ -494,6 +526,7 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
     }
 
     override def toString: String = s"recovery started (replayMax = [$replayMax])"
+
     override def recoveryRunning: Boolean = true
 
     override def stateReceive(receive: Receive, message: Any) = try message match {
@@ -651,7 +684,9 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
           try {
             peekApplyHandler(p.payload)
             onWriteMessageComplete(err = false)
-          } catch { case NonFatal(e) ⇒ onWriteMessageComplete(err = true); throw e }
+          } catch {
+            case NonFatal(e) ⇒ onWriteMessageComplete(err = true); throw e
+          }
         }
       case WriteMessageRejected(p, cause, id) ⇒
         // instanceId mismatch can happen for persistAsync and defer in case of actor restart
@@ -675,7 +710,9 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
           try {
             peekApplyHandler(l)
             onWriteMessageComplete(err = false)
-          } catch { case NonFatal(e) ⇒ onWriteMessageComplete(err = true); throw e }
+          } catch {
+            case NonFatal(e) ⇒ onWriteMessageComplete(err = true); throw e
+          }
         }
       case WriteMessagesSuccessful ⇒
         writeInProgress = false
@@ -705,7 +742,9 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
       else try {
         Eventsourced.super.aroundReceive(receive, message)
         aroundReceiveComplete(err = false)
-      } catch { case NonFatal(e) ⇒ aroundReceiveComplete(err = true); throw e }
+      } catch {
+        case NonFatal(e) ⇒ aroundReceiveComplete(err = true); throw e
+      }
 
     private def aroundReceiveComplete(err: Boolean): Unit = {
       if (eventBatch.nonEmpty) flushBatch()

akka-persistence/src/main/scala/akka/persistence/Persistence.scala

@@ -12,7 +12,7 @@ import akka.event.{ Logging, LoggingAdapter }
 import akka.persistence.journal.{ EventAdapters, IdentityEventAdapters }
 import akka.util.Collections.EmptyImmutableSeq
 import akka.util.Helpers.ConfigOps
-import com.typesafe.config.Config
+import com.typesafe.config.{ Config, ConfigFactory }
 
 import scala.annotation.tailrec
 import scala.concurrent.duration._
@@ -68,6 +68,7 @@ final class PersistenceSettings(config: Config) {
     }
 
   }
+
 }
 
 /**
@@ -82,7 +83,7 @@ trait PersistenceIdentity {
   def persistenceId: String
 
   /**
-   * Configuration id of the journal plugin servicing this persistent actor or view.
+   * Configuration id of the journal plugin servicing this persistent actor.
    * When empty, looks in `akka.persistence.journal.plugin` to find configuration entry path.
    * When configured, uses `journalPluginId` as absolute path to the journal configuration entry.
    * Configuration entry must contain few required fields, such as `class`. See `src/main/resources/reference.conf`.
@@ -90,14 +91,14 @@ trait PersistenceIdentity {
   def journalPluginId: String = ""
 
   /**
-   * Configuration id of the snapshot plugin servicing this persistent actor or view.
+   * Configuration id of the snapshot plugin servicing this persistent actor.
    * When empty, looks in `akka.persistence.snapshot-store.plugin` to find configuration entry path.
    * When configured, uses `snapshotPluginId` as absolute path to the snapshot store configuration entry.
    * Configuration entry must contain few required fields, such as `class`. See `src/main/resources/reference.conf`.
    */
   def snapshotPluginId: String = ""
-
 }
+
 //#persistence-identity
 
 trait PersistenceRecovery {
@@ -110,6 +111,7 @@ trait PersistenceRecovery {
    * To skip recovery completely return `Recovery.none`.
    */
   def recovery: Recovery = Recovery()
+
   //#persistence-recovery
 }
 
@@ -122,14 +124,41 @@ trait PersistenceStash extends Stash with StashFactory {
     Persistence(context.system).defaultInternalStashOverflowStrategy
 }
 
+trait RuntimePluginConfig {
+  /**
+   * Additional configuration of the journal plugin servicing this persistent actor.
+   * When empty, the whole configuration of the journal plugin will be taken from the [[Config]] loaded into the
+   * [[ActorSystem]].
+   * When configured, the journal plugin configuration will be taken from this [[Config]] merged with the [[Config]]
+   * loaded into the [[ActorSystem]].
+   *
+   * @return an additional configuration used to configure the journal plugin.
+   */
+  def journalPluginConfig: Config
+
+  /**
+   * Additional configuration of the snapshot plugin servicing this persistent actor.
+   * When empty, the whole configuration of the snapshot plugin will be taken from the [[Config]] loaded into the
+   * [[ActorSystem]].
+   * When configured, the snapshot plugin configuration will be taken from this [[Config]] merged with the [[Config]]
+   * loaded into the [[ActorSystem]].
+   *
+   * @return an additional configuration used to configure the snapshot plugin.
+   */
+  def snapshotPluginConfig: Config
+}
+
 /**
  * Persistence extension provider.
  */
 object Persistence extends ExtensionId[Persistence] with ExtensionIdProvider {
   /** Java API. */
   override def get(system: ActorSystem): Persistence = super.get(system)
+
   def createExtension(system: ExtendedActorSystem): Persistence = new Persistence(system)
+
   def lookup() = Persistence
+
   /** INTERNAL API. */
   private[persistence] case class PluginHolder(actor: ActorRef, adapters: EventAdapters, config: Config)
     extends Extension
@@ -145,6 +174,7 @@ object Persistence extends ExtensionId[Persistence] with ExtensionIdProvider {
  * Persistence extension.
  */
 class Persistence(val system: ExtendedActorSystem) extends Extension {
+
   import Persistence._
 
   private def log: LoggingAdapter = Logging(system, getClass.getName)
@@ -215,8 +245,19 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
    * adapter for each class, otherwise the most specific adapter matching a given class will be returned.
    */
   final def adaptersFor(journalPluginId: String): EventAdapters = {
+    adaptersFor(journalPluginId: String, ConfigFactory.empty)
+  }
+
+  /**
+   * Returns an [[akka.persistence.journal.EventAdapters]] object which serves as a per-journal collection of bound event adapters.
+   * If no adapters are registered for a given journal the EventAdapters object will simply return the identity
+   * adapter for each class, otherwise the most specific adapter matching a given class will be returned.
+   *
+   * The provided journalPluginConfig will be used to configure the plugin instead of the actor system config.
+   */
+  final def adaptersFor(journalPluginId: String, journalPluginConfig: Config): EventAdapters = {
     val configPath = if (isEmpty(journalPluginId)) defaultJournalPluginId else journalPluginId
-    pluginHolderFor(configPath, JournalFallbackConfigPath).adapters
+    pluginHolderFor(configPath, JournalFallbackConfigPath, journalPluginConfig).adapters
   }
 
   /**
@@ -238,9 +279,9 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
    * When empty, looks in `akka.persistence.journal.plugin` to find configuration entry path.
    * When configured, uses `journalPluginId` as absolute path to the journal configuration entry.
    */
-  private[akka] final def journalConfigFor(journalPluginId: String): Config = {
+  private[akka] final def journalConfigFor(journalPluginId: String, journalPluginConfig: Config = ConfigFactory.empty): Config = {
     val configPath = if (isEmpty(journalPluginId)) defaultJournalPluginId else journalPluginId
-    pluginHolderFor(configPath, JournalFallbackConfigPath).config
+    pluginHolderFor(configPath, JournalFallbackConfigPath, journalPluginConfig).config
   }
 
   /**
@@ -262,9 +303,9 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
    * When configured, uses `journalPluginId` as absolute path to the journal configuration entry.
    * Configuration entry must contain few required fields, such as `class`. See `src/main/resources/reference.conf`.
    */
-  private[akka] final def journalFor(journalPluginId: String): ActorRef = {
+  private[akka] final def journalFor(journalPluginId: String, journalPluginConfig: Config = ConfigFactory.empty): ActorRef = {
     val configPath = if (isEmpty(journalPluginId)) defaultJournalPluginId else journalPluginId
-    pluginHolderFor(configPath, JournalFallbackConfigPath).actor
+    pluginHolderFor(configPath, JournalFallbackConfigPath, journalPluginConfig).actor
   }
 
   /**
@@ -275,20 +316,20 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
    * When configured, uses `snapshotPluginId` as absolute path to the snapshot store configuration entry.
    * Configuration entry must contain few required fields, such as `class`. See `src/main/resources/reference.conf`.
    */
-  private[akka] final def snapshotStoreFor(snapshotPluginId: String): ActorRef = {
+  private[akka] final def snapshotStoreFor(snapshotPluginId: String, snapshotPluginConfig: Config = ConfigFactory.empty): ActorRef = {
     val configPath = if (isEmpty(snapshotPluginId)) defaultSnapshotPluginId else snapshotPluginId
-    pluginHolderFor(configPath, SnapshotStoreFallbackConfigPath).actor
+    pluginHolderFor(configPath, SnapshotStoreFallbackConfigPath, snapshotPluginConfig).actor
   }
 
-  @tailrec private def pluginHolderFor(configPath: String, fallbackPath: String): PluginHolder = {
+  @tailrec private def pluginHolderFor(configPath: String, fallbackPath: String, additionalConfig: Config): PluginHolder = {
     val extensionIdMap = pluginExtensionId.get
     extensionIdMap.get(configPath) match {
       case Some(extensionId) ⇒
         extensionId(system)
       case None ⇒
-        val extensionId = new PluginHolderExtensionId(configPath, fallbackPath)
+        val extensionId = new PluginHolderExtensionId(configPath, fallbackPath, additionalConfig)
         pluginExtensionId.compareAndSet(extensionIdMap, extensionIdMap.updated(configPath, extensionId))
-        pluginHolderFor(configPath, fallbackPath) // Recursive invocation.
+        pluginHolderFor(configPath, fallbackPath, additionalConfig) // Recursive invocation.
     }
   }
 
@@ -310,14 +351,16 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
         try {
           Reflect.findConstructor(pluginClass, List(pluginConfig)) // will throw if not found
           List(pluginConfig)
-        } catch { case NonFatal(_) ⇒ Nil } // otherwise use empty constructor
+        } catch {
+          case NonFatal(_) ⇒ Nil
+        } // otherwise use empty constructor
     }
     val pluginActorProps = Props(Deploy(dispatcher = pluginDispatcherId), pluginClass, pluginActorArgs)
     system.systemActorOf(pluginActorProps, pluginActorName)
   }
 
-  private def createAdapters(configPath: String): EventAdapters = {
+  private def createAdapters(configPath: String, additionalConfig: Config): EventAdapters = {
-    val pluginConfig = system.settings.config.getConfig(configPath)
+    val pluginConfig = additionalConfig.withFallback(system.settings.config).getConfig(configPath)
     EventAdapters(system, pluginConfig)
   }
 
@@ -326,15 +369,18 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
 
   private def id(ref: ActorRef) = ref.path.toStringWithoutAddress
 
-  private class PluginHolderExtensionId(configPath: String, fallbackPath: String) extends ExtensionId[PluginHolder] {
+  private class PluginHolderExtensionId(configPath: String, fallbackPath: String, additionalConfig: Config) extends ExtensionId[PluginHolder] {
+    def this(configPath: String, fallbackPath: String) = this(configPath, fallbackPath, ConfigFactory.empty)
+
     override def createExtension(system: ExtendedActorSystem): PluginHolder = {
+      val mergedConfig = additionalConfig.withFallback(system.settings.config)
       require(
-        !isEmpty(configPath) && system.settings.config.hasPath(configPath),
+        !isEmpty(configPath) && mergedConfig.hasPath(configPath),
         s"'reference.conf' is missing persistence plugin config path: '$configPath'")
-      val config: Config = system.settings.config.getConfig(configPath)
+      val config: Config = mergedConfig.getConfig(configPath)
-        .withFallback(system.settings.config.getConfig(fallbackPath))
+        .withFallback(mergedConfig.getConfig(fallbackPath))
       val plugin: ActorRef = createPlugin(configPath, config)
-      val adapters: EventAdapters = createAdapters(configPath)
+      val adapters: EventAdapters = createAdapters(configPath, mergedConfig)
 
       PluginHolder(plugin, adapters, config)
     }

akka-persistence/src/test/scala/akka/persistence/PersistenceSpec.scala

@@ -44,6 +44,12 @@ abstract class PersistenceSpec(config: Config) extends AkkaSpec(config) with Bef
   def namedPersistentActor[T <: NamedPersistentActor: ClassTag] =
     system.actorOf(Props(implicitly[ClassTag[T]].runtimeClass, name))
 
+  /**
+   * Creates a persistent actor with current name as constructor argument, plus a custom [[Config]]
+   */
+  def namedPersistentActorWithProvidedConfig[T <: NamedPersistentActor: ClassTag](providedConfig: Config) =
+    system.actorOf(Props(implicitly[ClassTag[T]].runtimeClass, name, providedConfig))
+
   override protected def beforeEach() {
     _name = s"${namePrefix}-${counter.incrementAndGet()}"
   }