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Merge pull request #18188 from akka/wip-17844-persistence-dispatcher-patriknw

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=per #17844 Clarify docs around journal dispatchers
This commit is contained in:
Patrik Nordwall 2015-08-13 13:14:40 +02:00
commit 20352562e1
5 changed files with 45 additions and 16 deletions
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15
akka-docs/rst/java/lambda-persistence.rst
View file

@ -688,8 +688,13 @@ A journal plugin can be activated with the following minimal configuration:
.. includecode:: ../scala/code/docs/persistence/PersistencePluginDocSpec.scala#journal-plugin-config
The specified plugin ``class`` must have a no-arg constructor. The ``plugin-dispatcher`` is the dispatcher
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``
for ``SyncWriteJournal`` plugins and ``akka.actor.default-dispatcher`` for ``AsyncWriteJournal`` plugins.
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``.
The journal plugin instance is an actor so the methods corresponding to requests from persistent actors
are executed sequentially. It may delegate to asynchronous libraries, spawn futures, or delegate to other
actors to achive parallelism.
Don't run journal tasks/futures on the system default dispatcher, since that might starve other tasks.
Snapshot store plugin API
-------------------------
@ -705,6 +710,12 @@ A snapshot store plugin can be activated with the following minimal configuratio
The specified plugin ``class`` must have a no-arg constructor. The ``plugin-dispatcher`` is the dispatcher
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``.
The snapshot store instance is an actor so the methods corresponding to requests from persistent actors
are executed sequentially. It may delegate to asynchronous libraries, spawn futures, or delegate to other
actors to achive parallelism.
Don't run snapshot store tasks/futures on the system default dispatcher, since that might starve other tasks.
Pre-packaged plugins
====================

15
akka-docs/rst/java/persistence.rst
View file

@ -693,8 +693,13 @@ A journal plugin can be activated with the following minimal configuration:
.. includecode:: ../scala/code/docs/persistence/PersistencePluginDocSpec.scala#journal-plugin-config
The specified plugin ``class`` must have a no-arg constructor. The ``plugin-dispatcher`` is the dispatcher
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``
for ``SyncWriteJournal`` plugins and ``akka.actor.default-dispatcher`` for ``AsyncWriteJournal`` plugins.
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``.
The journal plugin instance is an actor so the methods corresponding to requests from persistent actors
are executed sequentially. It may delegate to asynchronous libraries, spawn futures, or delegate to other
actors to achive parallelism.
Don't run journal tasks/futures on the system default dispatcher, since that might starve other tasks.
Snapshot store plugin API
-------------------------
@ -710,6 +715,12 @@ A snapshot store plugin can be activated with the following minimal configuratio
The specified plugin ``class`` must have a no-arg constructor. The ``plugin-dispatcher`` is the dispatcher
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``.
The snapshot store instance is an actor so the methods corresponding to requests from persistent actors
are executed sequentially. It may delegate to asynchronous libraries, spawn futures, or delegate to other
actors to achive parallelism.
Don't run snapshot store tasks/futures on the system default dispatcher, since that might starve other tasks.
Plugin TCK
----------
In order to help developers build correct and high quality storage plugins, we provide an Technology Compatibility Kit (`TCK <http://en.wikipedia.org/wiki/Technology_Compatibility_Kit>`_ for short).

15
akka-docs/rst/scala/persistence.rst
View file

@ -745,8 +745,13 @@ A journal plugin can be activated with the following minimal configuration:
.. includecode:: code/docs/persistence/PersistencePluginDocSpec.scala#journal-plugin-config
The specified plugin ``class`` must have a no-arg constructor. The ``plugin-dispatcher`` is the dispatcher
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``
for ``SyncWriteJournal`` plugins and ``akka.actor.default-dispatcher`` for ``AsyncWriteJournal`` plugins.
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``.
The journal plugin instance is an actor so the methods corresponding to requests from persistent actors
are executed sequentially. It may delegate to asynchronous libraries, spawn futures, or delegate to other
actors to achive parallelism.
Don't run journal tasks/futures on the system default dispatcher, since that might starve other tasks.
Snapshot store plugin API
-------------------------
@ -762,6 +767,12 @@ A snapshot store plugin can be activated with the following minimal configuratio
The specified plugin ``class`` must have a no-arg constructor. The ``plugin-dispatcher`` is the dispatcher
used for the plugin actor. If not specified, it defaults to ``akka.persistence.dispatchers.default-plugin-dispatcher``.
The snapshot store instance is an actor so the methods corresponding to requests from persistent actors
are executed sequentially. It may delegate to asynchronous libraries, spawn futures, or delegate to other
actors to achive parallelism.
Don't run snapshot store tasks/futures on the system default dispatcher, since that might starve other tasks.
Plugin TCK
----------
In order to help developers build correct and high quality storage plugins, we provide an Technology Compatibility Kit (`TCK <http://en.wikipedia.org/wiki/Technology_Compatibility_Kit>`_ for short).

4
akka-persistence/src/main/resources/reference.conf
View file

@ -63,6 +63,7 @@ akka.persistence {
type = PinnedDispatcher
executor = "thread-pool-executor"
}
# Default dispatcher for message replay.
default-replay-dispatcher {
type = Dispatcher
executor = "fork-join-executor"
@ -71,6 +72,7 @@ akka.persistence {
parallelism-max = 8
}
}
# Default dispatcher for streaming snapshot IO
default-stream-dispatcher {
type = Dispatcher
executor = "fork-join-executor"
@ -176,7 +178,7 @@ akka.persistence.journal.leveldb-shared {
# Dispatcher for shared store actor.
store-dispatcher = "akka.persistence.dispatchers.default-plugin-dispatcher"
# Dispatcher for message replay.
replay-dispatcher = "akka.persistence.dispatchers.default-plugin-dispatcher"
replay-dispatcher = "akka.persistence.dispatchers.default-replay-dispatcher"
# Storage location of LevelDB files.
dir = "journal"
# Use fsync on write.

12
akka-persistence/src/main/scala/akka/persistence/Persistence.scala
View file

@ -161,12 +161,6 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
val settings = new PersistenceSettings(config)
private def journalDispatchSelector(klaz: Class[_]): String =
if (classOf[AsyncWriteJournal].isAssignableFrom(klaz)) Dispatchers.DefaultDispatcherId else DefaultPluginDispatcherId // TODO sure this is not inverted?
private def snapshotDispatchSelector(klaz: Class[_]): String =
DefaultPluginDispatcherId
/** Check for default or missing identity. */
private def isEmpty(text: String) = text == null || text.length == 0
@ -247,7 +241,7 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
}
}
private def createPlugin(configPath: String)(dispatcherSelector: Class[_] ⇒ String) = {
private def createPlugin(configPath: String): ActorRef = {
require(!isEmpty(configPath) && system.settings.config.hasPath(configPath),
s"'reference.conf' is missing persistence plugin config path: '$configPath'")
val pluginActorName = configPath
@ -256,7 +250,7 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
log.debug(s"Create plugin: $pluginActorName $pluginClassName")
val pluginClass = system.dynamicAccess.getClassFor[Any](pluginClassName).get
val pluginInjectConfig = if (pluginConfig.hasPath("inject-config")) pluginConfig.getBoolean("inject-config") else false
val pluginDispatcherId = if (pluginConfig.hasPath("plugin-dispatcher")) pluginConfig.getString("plugin-dispatcher") else dispatcherSelector(pluginClass)
val pluginDispatcherId = if (pluginConfig.hasPath("plugin-dispatcher")) pluginConfig.getString("plugin-dispatcher") else DefaultPluginDispatcherId
val pluginActorArgs = if (pluginInjectConfig) List(pluginConfig) else Nil
val pluginActorProps = Props(Deploy(dispatcher = pluginDispatcherId), pluginClass, pluginActorArgs)
system.systemActorOf(pluginActorProps, pluginActorName)
@ -274,7 +268,7 @@ class Persistence(val system: ExtendedActorSystem) extends Extension {
private class PluginHolderExtensionId(configPath: String) extends ExtensionId[PluginHolder] {
override def createExtension(system: ExtendedActorSystem): PluginHolder = {
val plugin = createPlugin(configPath)(journalDispatchSelector)
val plugin = createPlugin(configPath)
val adapters = createAdapters(configPath)
PluginHolder(plugin, adapters)
}