Potamus

Potamus is a simple utility that helps with building consistent Docker images of applications.

The usual process for building images is to simply run docker build followed by docker push. However, in reality, you need to do other things.

Potamus mandates that you'll create an image with a tag that matches the Git commit ref of the code that exist in the image. For example, if your image is called myapp, when you build, you'll have an image myorg/myapp:871c4832a8071aaa5fcaeaca1121dbe6962af218. In addtion to your commit-tagged image, it also pushes a tag with the name of the branch that you're building from. For example, if you're on your v1.0 branch you'll also find the image is tagged with v1.0.

$ gem install potamus

Create a PotamusFile in the root of your application alongside your Dockerfile.

# At the most basic, you just need to specify the name
# of the image you wish to create.
image_name: apps/postal

Once you've added these, just run the build command:

$ cd path/to/app
$ potamus build

# If you wish to also push after building
$ potamus build --push

# If you just want to test your Dockerfile.
# When using test you don't need a clean repository or
# to have pushed the code. It will only be pushed using the
# `test` tag.
$ potamus build --test

# If you want to test and push your test
$ potamus build --test --push

Additional configuration can be specified in the PotamusFile.

• remote_name - the name of the authoritative remote for your repository (defaults to origin).

• branch_for_latest - when pushing for the named branch a tag named latest will also be created (defaults to master).

• buildkit - if set to true, the build command will be instructed to use Docker BuildKit

• build_options - an array of additional options to provide to the docker build command