开源软件名称：

akka-data-replication

开源软件地址：

https://gitee.com/mefaso/akka-data-replication

开源软件介绍：

本项目已经成为akka实验项目将在akka2.4支持

Akka Data Replication

This is an EARLY PREVIEW of a library for replication of data in an Akka cluster.It is a replicated in-memory data store supporting low latency and high availabilityrequirements. The data must be so called Conflict Free Replicated Data Types (CRDTs),i.e. they provide a monotonic merge function and the state changes always converge.

For good introduction to CRDTs you should watch theEventually Consistent Data Structurestalk by Sean Cribbs.

CRDTs can't be used for all types of problems, but when they can they have very nice properties:

low latency of both read and writes
high availability (partition tolerance)
scalable (no central coordinator)
strong eventual consistency (eventual consistency without conflicts)

Built in data types:

Counters: GCounter, PNCounter
Registers: LWWRegister, Flag
Sets: GSet, ORSet
Maps: ORMap, LWWMap, PNCounterMap

You can use your own custom data types by implementing the merge function of the ReplicatedDatatrait. Note that CRDTs typically compose nicely, i.e. you can use the provided data types to build richerdata structures.

The Replicator actor implements the infrastructure for replication of the data. It usesdirect replication and gossip based dissemination. The Replicator actor is started on each nodein the cluster, or group of nodes tagged with a specific role. It communicates with otherReplicator instances with the same path (without address) that are running on other nodes.For convenience it is typically used with the DataReplication Akka extension.

A short example of how to use it:

class DataBot extends Actor with ActorLogging {  import DataBot._  import Replicator._  val replicator = DataReplication(context.system).replicator  implicit val cluster = Cluster(context.system)  import context.dispatcher  val tickTask = context.system.scheduler.schedule(5.seconds, 5.seconds, self, Tick)  replicator ! Subscribe("key", self)  def receive = {    case Tick =>      val s = ThreadLocalRandom.current().nextInt(97, 123).toChar.toString      if (ThreadLocalRandom.current().nextBoolean()) {        // add        log.info("Adding: {}", s)        replicator ! Update("key", ORSet(), WriteLocal)(_ + s)      } else {        // remove        log.info("Removing: {}", s)        replicator ! Update("key", ORSet(), WriteLocal)(_ - s)      }    case _: UpdateResponse => // ignore    case Changed("key", data: ORSet) =>      log.info("Current elements: {}", data.value)  }  override def postStop(): Unit = tickTask.cancel()}

The full source code for this sample is inDataBot.scala.

More detailed documentation can be found in theScalaDocof Replicator and linked classes.

Two other examples:

Dependency

Latest version of akka-data-replication is 0.8. This version depends on Akka 2.3.6 and iscross-built against Scala 2.10.4 and 2.11.4.

Add the following lines to your build.sbt file:

resolvers += "patriknw at bintray" at "http://dl.bintray.com/patriknw/maven"libraryDependencies += "com.github.patriknw" %% "akka-data-replication" % "0.8"