Using docker-compose & mysql with CircleCI

Posted on:August 18, 2016

My Elixir/Phoenix application uses docker-compose and mysql. I decided on CircleCI for continuous-integration (CI) for its free container support. There were a few problems making it all run inside the CircleCI container environment.

CircleCI defaults to a docker version < v1.10.

Since I am using docker-compose locally, I also want to use the same setup during CI. Docker-compose requires a docker server whose version is greater or equal to v1.10. I override the existing docker version on the CircleCI container host through the machine mapping.

# circle.yml
machine:
  pre:
    - curl -sSL https://s3.amazonaws.com/circle-downloads/install-circleci-docker.sh | bash -s -- 1.10.0

Docker-compose is not available on the container host by default.

I need to install docker-compose after installing the required docker version.

# circle.yml
dependencies:
  pre:
    - curl -L https://github.com/docker/compose/releases/download/1.8.0-rc2/docker-compose-`uname -s`-`uname -m` > ../bin/docker-compose && chmod +x ../bin/docker-compose

MySQL is installed on the container host (port conflict).

My application uses mysql. Docker-compose setup starts mysql on port 3306. The 3306 port is the default mysql port and conflicts with the mysql-server installation on the host container. I remove the host’s mysql installation.

# circle.yml
machine:
  pre:
    - sudo apt-get --purge autoremove -y mysql-server

Full configuration

# circle.yml
machine:
  pre:
    - curl -sSL https://s3.amazonaws.com/circle-downloads/install-circleci-docker.sh | bash -s -- 1.10.0
    - sudo apt-get --purge autoremove -y mysql-server
  services:
    - docker
dependencies:
  pre:
    - curl -L https://github.com/docker/compose/releases/download/1.8.0-rc2/docker-compose-`uname -s`-`uname -m` > ../bin/docker-compose && chmod +x ../bin/docker-compose
    - docker-compose pull
  override:
    - echo 'skip dependencies-override'
test:
  pre:
    - echo 'skip test-pre'
  override:
    - docker-compose up mysql:
        background: true
    - bin/wait_for_mysql
    - bin/app.ci

I override the dependencies and pre-test mappings with echo statements because:

  1. CircleCI infers the wrong dependencies for my app.
  2. CircleCI infers the wrong pre-test actions for my app.

My helper script, bin/app.ci pulls the app dependencies and properly runs my tests.

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