docker-it-scala

Set of utility classes to make integration testing with dockerised services in Scala easy.

You can read about reasoning behind it at Finely Distributed.

Setup

docker-it-scala can work with two underlying libraries to communicate to docker engine through REST API or unix socket. - Spotify's docker-client (used in Whisk) - docker-java

Note: there is no specific recommendation to use one of them, over the other, but we hear people using Spotify's one more often, so you might get better support for it.

There are separate artifacts available for these libraries:

Spotify's docker-client

libraryDependencies ++= Seq(
  "com.whisk" %% "docker-testkit-scalatest" % "0.9.9" % "test",
  "com.whisk" %% "docker-testkit-impl-spotify" % "0.9.9" % "test")

docker-java

libraryDependencies ++= Seq(
  "com.whisk" %% "docker-testkit-scalatest" % "0.9.9" % "test",
  "com.whisk" %% "docker-testkit-impl-docker-java" % "0.9.9" % "test")

You don't necessarily have to use

scalatest

Overriding execution environment

If you need to have custom setup for you environment, you need to override

dockerFactory

DockerClient

import com.spotify.docker.client.{DefaultDockerClient, DockerClient}
import com.whisk.docker.{DockerFactory, DockerKit}

trait MyCustomDockerKitSpotify extends DockerKit {
  private val client: DockerClient = DefaultDockerClient.fromEnv().build()
  override implicit val dockerFactory: DockerFactory = new SpotifyDockerFactory(client)
}

Check docker-client library project for configuration options.

Configuration

You should be able to provide configuration purely through environment variables.

Examples:

export DOCKER_HOST=tcp://127.0.0.1:2375

export DOCKER_HOST=unix:///var/run/docker.sock

Sample Services

• Cassandra
• Elasticsearch
• Kafka
• Mongodb
• Neo4j
• Postgres

Defining Containers

There are two ways to define a docker container.

Code based definitions and via

typesafe-config

Code based definitions

import com.whisk.docker.{DockerContainer, DockerKit, DockerReadyChecker}

trait DockerMongodbService extends DockerKit {
  val DefaultMongodbPort = 27017
  val mongodbContainer = DockerContainer("mongo:3.0.6")
    .withPorts(DefaultMongodbPort -> None)
    .withReadyChecker(DockerReadyChecker.LogLineContains("waiting for connections on port"))
    .withCommand("mongod", "--nojournal", "--smallfiles", "--syncdelay", "0")
  abstract override def dockerContainers: List[DockerContainer] =
    mongodbContainer :: super.dockerContainers
}

You can check usage example

Typesafe Configuration

docker-testkit-config

application.conf

The container definitions are nested in the structure of name

docker

docker {
...
...
}

See application.conf for more examples.

Usage in code

trait DockerMongodbService extends DockerKitConfig {

  val mongodbContainer = configureDockerContainer("docker.mongodb")
  abstract override def dockerContainers: List[DockerContainer] =
    mongodbContainer :: super.dockerContainers
}

Container Paths

• Cassandra =>

  docker.cassandra

• Elasticsearch =>

  docker.elasticsearch

• Kafka =>

  docker.kafka

• Mongodb =>

  docker.mongo

• Neo4j =>

  docker.neo4j

• Postgres =>

  docker.postgres

Fields

• image-name

  required (String)

• environmental-variables

  optional (Array of Strings)

• ready-checker

  optional structure

  • log-line

    optional (String)

  • http-response-code

  • code

    optional (Int - defaults to

    200

    )

  • port

    required (Int)

  • path

    optional (String - defaults to

    /

    )

  • within

    optional (Int)

  • looped

    optional structure

    • attempts

      required (Int)

    • delay

      required (Int)

• port-maps

  optional structure (list of structures)

  • SOME_MAPPING_NAME

  • internal

    required (Int)

  • external

    optional (Int)

• volume-maps

  optional structure (list of structures)

  • container

    required (String)

  • host

    required (String)

  • rw

    optional (Boolean - default:false)

Testkit

There are two testkits available -- one for

scalatest

specs2

Both set up the necessary docker containers and check that they are ready BEFORE any test is run, and doesn't close the container until ALL the tests are run.

Using in ScalaTest:

class MyMongoSpec extends FlatSpec with Matchers with DockerMongodbService {
  ...
}

With Multiple containers:

class AllAtOnceSpec extends FlatSpec with Matchers with BeforeAndAfterAll with GivenWhenThen with ScalaFutures
    with DockerElasticsearchService with DockerCassandraService with DockerNeo4jService with DockerMongodbService {

  implicit val pc = PatienceConfig(Span(20, Seconds), Span(1, Second))
  "all containers" should "be ready at the same time" in {
    dockerContainers.map(.image).foreach(println)
    dockerContainers.forall(.isReady().futureValue) shouldBe true
  }
}

Using in Specs2

Examples can be found in the specs2 module's tests