jenkins-docker-encaps

Usage

Along with this image is provided a script called encaps (and encaps-cleanup) that are used to encapsulate a script execution within a container.

For instance, let's assume the following script:

#!/bin/sh
python setup.py bdist_egg

If you want to encapsulate such script in a containerized environment, it is (almost) as simple as replacing the shebang:

#!/usr/bin/encaps
python setup.py bdist_egg

Behavior of the script is defined by the following env variables:

• DOCKER_ENCAPS_IMG : image used to instantiate the container
• DOCKER_ENCAPS_ARGS : extra arguments that should be given to docker upon instantiation
• DOCKER_ENCAPS_NAME : name used for the container, default to BUILD_TAG which is usually provided by Jenkins, format is jenkins-<JOB>-<BUILD_ID>
• DOCKER_ENCAPS_SHELL : to control the actual program executing your script, default to /bin/sh

As it needs a running container, the script will instanciate one the first time encaps is run.

Once you are done with the container, you should call encaps-cleanup to remove it or it will stay running in the background.

In the example above, consider that you want to build your application with python 2.7.9. Just inject the variable DOCKER_ENCAPS_IMG=python:2.7.9 and it will use the image from https://registry.hub.docker.com/_/python/ to encapsulate your build.

Limitations

• Do not forget that even if the docker client is running in the Jenkins container, the server is still on the host. Therefore, paths, etc ... should be relative/accessible from the host.
• The workspace is considered as being a shared volume between the jenkins-slave container and the host for this reason.