The Docker Image Patcher with its command docker-image-patch is a tool to take an existing
Docker image, apply a patchset onto it and then rebuild a new image off of this. Patches can
either be supplied in .patch file format or can be generated from a git repository.
As usual, python3 required, virtualenv recommended. Make sure your pip is a python3-pip.
$ pip install git+https://github.com/sapcc/docker-image-patcherYou need at least:
- the base Docker image that should be patched (
--base-image) - a repository path aka new image name (
--repository) - at least one patch, either as file (
--patch) or from a git (--git)
You can also add:
- a list of new tags for the new Docker image (
--tags)
A patch is defined by a source and a docker-workdir. The docker-workdir is the path inside
the Docker image where the patch can be applied with git apply (similar to patch -p1). This is
generally the path inside the image where the application is installed that is about to be patched.
With --git a patch can be automatically generated from a local git repository. This option takes
one to three arguments in the format of [[path/to/git] git-ref] <docker-workdir>]. path/to/git
refers to the path to the git repo and defaults to .. git-ref can be any git reference, e.g. a
commit hash or a range, which will then be given to git diff to create the patch. The defaul is
HEAD, which will result in a patch with all uncommited changes.
--patch takes a list of patches that will be applied. Multiple patches can be specified for each
--patch.
--git and --patch can be used multiple times. The order in which they are supplied matters, as
this is also the order the patches are applied in.
Other convenience functions include running commands inside the image via -c / --run-before or
--run-after and copying files or directories into the image via --copy.
Add patch blubb.patch to image foo:latest, resulting in an image bar:special-fix:
$ docker-image-patch -b foo:latest -r bar -t special-fix -p blubb.patch /var/lib/my-app/Add uncommited changes in local git to image:
$ docker-image-patch -b foo:latest -r bar -t special-fix -g /var/lib/my-app/Add a set of commits from the current repository:
$ docker-image-patch -b foo:latest -r bar -t special-fix -g ef69b187..58a94380 /var/lib/my-app/Add a set of commits from another repository and a set of patches:
$ docker-image-patch -b foo:latest -r bar -t special-fix -g ~/repos/my-cool-repo/ ef69b187..58a94380 /var/lib/my-app/ -p patches/*.patch /var/lib/my-app/