###CI Builder The ci-builder is a docker container image used for building images with CI utilities such as Jenkins. It's a very simple image that installs docker-in-docker and then can be passed environment variables used with a volume mount to produce a built docker container as the output.

####Usage After building the docker image with a command like:

docker build --rm=true -t your-registry/ci-builder:latest .

You then use the following sinppet (or similar) in your Jenkins (or the like) CI project as a build step.

Simply set the REGISTRY_HOST variable and execute the following code in your Jenkins build.

REGISTRY_HOST=""

docker pull ${REGISTRY_HOST}/ci-builder:latest
PCWD=`pwd`
docker run --rm -t --privileged -v ${PCWD}:/builder -e DOCKER_REG_PREFIX=${REGISTRY_HOST} \
  -e DOCKER_BUILDER_OPTS="--dns x.x.x.x" -e GIT_COMMIT="${GIT_COMMIT}" -e BUILD_NUMBER="${BUILD_NUMBER}" \
  [-e DOCKER_BASE_IMG=""] ${REGISTRY_HOST}/ci-builder:latest /builder/ci-builder/jenkins-build.sh

Note. all the environment variables are optional, however, view their usage in our example scripts under the examples directory in this repo.

####Requirements You must have a build script that contains your build steps, (eg. jenkins-build.sh) and it must reside within your apps codebase. It's location is passed in as the CMD at the end of the docker run line. The build script is where the included environment variables are made use of. We have some examples in the Usage section above, which relate to our example script in the examples directory of this repo.