play-cassandra-evolutions

Module for Play framework 2.5 to apply evolutions to a cassandra database. Behaves mostly like the standard evolution module for JDBC based databases.

Usage

The current version is supposed to run with Play 2.5 only. Thre is also a slightly older version for Play 2.4

Add the following dependency to your project

libraryDependencies += "de.leanovate" %% "play-cassandra-evolutions" % "2.5.0"

Since there are many ways to configure the contact points to a cassandra cluster (with or without some sort of service discovery), so this module does not make any presumptions about it. Instead you have to provide your own implementation for the de.leanovate.play.cassandra.evolutions.CassandraEndpointConfig trait. The most simple implementation might look like this

import com.datastax.driver.core.Cluster
import com.google.inject.Inject
import play.api.inject.Module
import play.api.{Configuration, Environment}

class LocalhostEndpointsConfig extends CassandraEndpointConfig {
  override def databases: Seq[String] = Seq("cassandra")

  override def clusterForDatabase(db: String): Cluster =
    Cluster.builder().addContactPoints("localhost").build()
}

class CassandraConfigModule extends Module {
  override def bindings(environment: Environment, configuration: Configuration) = {
    Seq(
      bind[CassandraEndpointConfig].to[LocalhostEndpointsConfig]
    )
  }
}

Which you have to enable in your application.conf

play.modules.enabled += CassandraConfigModule

As usually evolutions can now be added to (in the example above dbname is just 'cassandra':

• conf/evolutions/dbname/1.cql
• conf/evolutions/dbname/2.cql
• ...

Also as usual, automatic evolutions have to be activated in your configuration or via system property. E.g.:

play.evolutions.autoApply=true 

Under the hood

Just like the standard play evolutions the current state is stored in the database itself. For this purpose the module creates an additional keyspace <dbname>_evolutions with a single table play_evolutions.

The main reason for an additional keyspace is to interfere with you production data as little as possible and to give you the opportunity to create the production keyspace (and its parameters) via evolution files.

License

MIT Licence