dcind (Docker-Compose-in-Docker)

Versioning

This repository and corresponding images on Docker Hub follow the semantic versioning rules. It is advised to not rely on the latest tag when using amidos/dcind image in your CI pipelines. Consider using a specific version, like amidos/dcind:1.

Usage

Use this Dockerfile to build a base image for your integration tests in Concourse CI. Alternatively, you can use a ready-to-use image from the Docker Hub: amidos/dcind. The image is Alpine based.

Here is an example of a Concourse job that uses amidos/dcind image to run a bunch of containers in a task, and then runs the integration test suite. You can find a full version of this example in the example directory.

Note that docker-lib.sh has bash dependencies, so it is important to use bash in your task.

  - name: integration
    plan:
      - aggregate:
        - get: code
          params: {depth: 1}
          passed: [unit-tests]
          trigger: true
        - get: redis
          params: {save: true}
        - get: busybox
          params: {save: true}
      - task: Run integration tests
        privileged: true
        config:
          platform: linux
          image_resource:
            type: docker-image
            source:
              repository: amidos/dcind
          inputs:
            - name: code
            - name: redis
            - name: busybox
          run:
            path: bash
            args:
              - -exc
              - |
                source /docker-lib.sh
                start_docker

                # Strictly speaking, preloading of Docker images is not required.
                # However, you might want to do this for a couple of reasons:
                # - If the image comes from a private repository, it is much easier to let Concourse pull it,
                #   and then pass it through to the task.
                # - When the image is passed to the task, Concourse can often get the image from its cache.
                docker load -i redis/image
                docker tag "$(cat redis/image-id)" "$(cat redis/repository):$(cat redis/tag)"

                docker load -i busybox/image
                docker tag "$(cat busybox/image-id)" "$(cat busybox/repository):$(cat busybox/tag)"

                # This is just to visually check in the log that images have been loaded successfully
                docker images

                # Run the container with tests and its dependencies.
                docker-compose -f code/example/integration.yml run tests

                # Cleanup.
                # Not sure if this is required.
                # It's quite possible that Concourse is smart enough to clean up the Docker mess itself.
                docker volume rm $(docker volume ls -q)