Ruby on Rails

services:
  # What to call the service hosting the site.
  rails:
    # Use a Tugboat Debian image as a starting point because it contains tools
    # and configurations to help them work well with Tugboat
    image: tugboatqa/debian

    # Set this as the default service. This does a few things
    #   1. Clones the git repository into the service container
    #   2. Exposes port 80 to the Tugboat HTTP proxy
    #   3. Routes requests to the Preview URL to this service
    default: true

    # Don't build the Ruby service until the database service is started
    depends: database

    # A set of commands to run while building this service
    commands:
      # Commands that set up the basic preview infrastructure
      init:
        # Check for updates to apt-get, and then use it to install Ruby
        - apt-get update
        - apt-get install ruby ruby-dev

        # Install a minimal set of PostgreSQL binaries and headers to interact with the database
        - apt-get install libpq-dev

        # Install the gems required for the project
        - gem update --system
        - gem install bundler
        - bundle install

        # Clean up apt artifacts to keep the Preview small
        - apt-get clean
        - rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

      # Commands that import files, databases,  or other assets. When an
      # existing preview is refreshed, the build workflow starts here,
      # skipping the init step, because the results of that step will
      # already be present.
      update:
        # A common practice in many Rails projects is to run this command to
        # set up a database. This step is why the 'database' service has an 'init'
        # command to give the default Tugboat user permission to create the database.
        # If you're not creating a database here, you don't need the 'init' and
        # 'online' commands in the `database` service. If you're connecting to a remote
        # database, you won't need this.
        - bin/rails db:setup

      # Commands that should happen every time the Preview starts.
      start:
        # Start the Rails server. The '&' trailing this statement puts the process
        # in the background.
        - bin/rails s -b 0.0.0.0 -p 80 &

  # What to call the service hosting the database. This name also acts as the
  # hostname to access the service by from the 'rails' service.
  database:
    # Use the latest available version of postgres by not specifying a
    # version
    image: tugboatqa/postgres

    # A set of commands to run while building this service
    commands:
      # Commands that import files, databases, or other assets. When an
      # existing preview is refreshed, the build workflow starts here,
      # skipping the init step, because the results of that step will
      # already be present.
      init:
        # Give the default Tugboat user the permission to create a database.
        # This is only required if using 'rails db:setup'
        - psql -U postgres -d tugboat -c "ALTER USER tugboat WITH CREATEDB;"