Run docker containers from a docker container

[alantrrs]

• emp should be a docker container
• emp should launch and build other containers using the following technique:

From here. The simplest way is to just expose the Docker socket to your CI container, by bind-mounting it with the -v flag.

Simply put, when you start your CI container (Jenkins or other), instead of hacking something together with Docker-in-Docker, start it with:

docker run -v /var/run/docker.sock:/var/run/docker.sock ...

Now this container will have access to the Docker socket, and will therefore be able to start containers. Except that instead of starting "child" containers, it will start "sibling" containers.

If your CI makes use of the Docker binary in scripts, you can include it in your CI image, or bind-mount it from the host was well. Example:

docker run -v /var/run/docker.sock:/var/run/docker.sock \
           -v $(which docker):/bin/docker \
           -ti ubuntu

[alantrrs]

• FIXME: nodegit doesn't build correctly on alpine linux. See https://github.com/cucumber/alpine-node-nodegit/blob/master/Dockerfile
• Need to figure out how to read the json stream from docker.buildImage correctly
• Tag the images
• Run the containers via docker
• Need to figure out how to mount the /data and /workspace volumes

[alantrrs]

moved remaining items to separate issues: #8 and #7