docker-image-testing-example

This is an example of using Serverspec to test Dockerfiles

Setup

This example assumes you have Docker installed, running and configured.

Ruby

This project uses rbenv to manage Ruby versions. Install it and the required Ruby version:

brew install rbenv ruby-build
rbenv install   # installs the version from .ruby-version

Add rbenv to your shell (add to ~/.zshrc or ~/.bashrc):

eval "$(rbenv init - zsh)"

Dependencies

Install gems with bundler:

bundle install

Pre-commit Hooks

Install pre-commit and set up the hooks:

brew install pre-commit
pre-commit install

Usage (running the tests)

bundle exec rake

The above will run Serverspec and using the docker-api gem it will

• Build a Docker image from the Docker file found in the top level directories (22 and 24)
• Create a container of that image,
• Run the tests found in spec/ on the container
• Delete the images and containers if the test was successful

The Dockerfiles are based on the official docker-node image.

You could also use the docker-api gem to pull existing images from the Docker hub and run tests against that image.

So for instance, a pull_image helper could look something like this:

  def pull_image(image)

    puts "Pulling image #{image}..."
    @image = Docker::Image.create('fromImage' => image)

    set :os, :family => 'debian'
    set :backend, :docker
    set :docker_image, @image.id

    puts "Running tests..."
  end

Reference

• Documentation for Serverspec can be found at http://serverspec.org/resource_types.html
• Documentation for the docker-api gem can be found at https://github.com/swipely/docker-api