Akka Persistence Redis Plugin

What is Akka Persistence Redis plugin?

This is a plugin for Akka Persistence that uses Redis as backend. It uses rediscala, an asynchronous Redis client written with Akka and Scala. It also depends on play-json for JSON serialization.

Compatibility

Scala 2.12 and Akka 2.4.x

Use versions from 0.7.0

resolvers += Resolver.jcenterRepo // Adds Bintray to resolvers for akka-persistence-redis and rediscala
libraryDependencies ++= Seq("com.hootsuite" %% "akka-persistence-redis" % "0.7.0")

Scala 2.11, Akka 2.4.x and Play 2.5.x

Use 0.6.0

resolvers += Resolver.jcenterRepo // Adds Bintray to resolvers for akka-persistence-redis and rediscala
libraryDependencies ++= Seq("com.hootsuite" %% "akka-persistence-redis" % "0.6.0")

Scala 2.11, Akka 2.4.x and Play 2.4.x

Use 0.5.0

resolvers += Resolver.jcenterRepo // Adds Bintray to resolvers for akka-persistence-redis and rediscala
libraryDependencies ++= Seq("com.hootsuite" %% "akka-persistence-redis" % "0.3.0")

Scala 2.11 and Akka 2.3.x

Use 0.2.2

resolvers += Resolver.jcenterRepo // Adds Bintray to resolvers for akka-persistence-redis and rediscala
libraryDependencies ++= Seq("com.hootsuite" %% "akka-persistence-redis" % "0.2.2")

Deprecated methods since Akka 2.3.4 are NOT implemented. As a result, some tests in TCK fail. Rest of methods are tested with the test harness included in this project.

SNAPSHOT

Development snapshots are published on JFrog OSS resolvers += "akka-persistence-redis" at "http://oss.jfrog.org/oss-snapshot-local"

Quick start guide

Installation

build.sbt

resolvers += Resolver.jcenterRepo // Adds Bintray to resolvers for akka-persistence-redis and rediscala
libraryDependencies ++= Seq("com.hootsuite" %% "akka-persistence-redis" % "0.4.0")

Activation

akka.persistence.journal.plugin = "akka-persistence-redis.journal"
akka.persistence.snapshot-store.plugin = "akka-persistence-redis.snapshot"

Redis config

From rediscala

redis {
  host = "localhost"
  port = 6379
  # optional
  password = "topsecret"
  db = 1
}

If using sentinel

redis {
  sentinel = true
  sentinel-master = "mymaster"  //master name
  sentinels = [{host :"localhost", port: 26379}] // list of sentinel addresses
}

Run Tests

Dockerfile is provided to set up Redis server to run tests.

# Build and start Redis docker container
docker build -t <your.name>/redis .
docker run -d -p 6379:6379 <your.name>/redis
# Run tests
sbt test
# Stop docker container
docker stop <container.id>

Usage

Redis keys

Journal and snapshot use "journal:" and "snapshot:" as part of keys respectively as it is a good practice to create namespace for keys reference The namespaces can be overriden using the akka-persistence-redis.journal.key-namespace and akka-persistence-redis.snapshot.key-namespace.

How is data stored in Redis?

In order to enforce ordering, journal entries and snapshots are inserted into Sorted Set and sorted by sequenceNr

Using custom ExecutionContext

By default, global ExecutionContext is used for Redis operation. This blocks calling thread for synchronous Akka Persistence APIs. Override JournalExecutionContext trait to use custom thread pool if blocking in global is undesirable.

trait CustomExecutionContext extends JournalExecutionContext {
  override implicit val ec: ExecutionContext = ExecutionContext.fromExecutorService(Executors.newSingleThreadExecutor())
}

How to contribute

Contribute by submitting a PR and a bug report in GitHub.

Maintainer

Steve Song @ssongvan