throw-if-null/docker-semver-github-action

GitHub action that build and pushes your images using SemVer tagging.

Info

This Action for Docker uses the SemVer version for image tagging.
That means that if you are pushing an image: docker push myimage:1.4.2
It will be tagged as latest and pushed, but also images:

• myimage:1.4
• myimage:1 will be tagged as latest and pushed.

This way when you specify in your Docker file:
FROM myimage:latest
you will pull version 1.4.2, but if you specify:
FROM myimage:1.4 or
FROM myimage:1
you will also pull the version 1.4.2

Now lets image that there is an image with version 1.3.6 and also 1.4.0 if you specify:
FROM myimage:1.3
it will pull the 1.3.6 (assuming that next version is 1.4.x) and if you specify:
FROM myimage:1.4.0
it will pul the version 1.4.0 although there is a more recent release (1.4.2).

This might not be useful to everyone but it does suite my needs.

Usage

name: Docker SemVer
on: [push]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@master
    - name: Publish to Registry
      uses: mirzamerdovic/docker-semver-github-action@master
      with:
        name: myDocker/repository
        username: ${{ secrets.DOCKER_USERNAME }}
        password: ${{ secrets.DOCKER_PASSWORD }}
        semver: 1.2.5

Arguments

Required:
name is the name of the image you would like to push
username the login username for the registry
password the login password for the registry

Optional:
semver: the tag name e.g. 1.2.3 (if ommited latest will be used as tag) dockerfile: when you would like to explicitly build a Dockerfile workdir if you need to change the work directory context when you would like to change the Docker build context. buildargs when you want to pass a list of environment variables as build-args. Identifiers are separated by comma.

Output

tag is the tag, which was pushed

Automatic versions via VERSION file

Action also supports a way of automatic version using the VERSION file.

VERSION file is a simple text file that contains the version number for example:
1.4.12

The action will try to extract the file from built image, so if you want to use it you will need to add it as a part of your repository and your Dockerfile.
Let's imagine that you have a VERSION file in the same folder as the Dockerfile. In the Dockerfile you'd need to add a line:
ADD VERSION .
so the VERSION file gets copied.

If you have done all this the action will extract the VERSION file and read the version value that will be used as a tag for your image.
If you think that all this is bollocks your build will still work without adding the VERSION file.

What's missing?

• I have no support for properly tagging images built from branches or PRs one would expect to be able to just specify 1.4.5 and when you are pushing an image from a branch to get a tag: 1.4.5-mybranch same goes for PR Current workaround for that is that you specify the suffix yourself.
• More tests

Credits

I need to say a big thank you to elghor who made Publish-Docker-Github-Action that I forked and built this one from. He also has some other useful actions that you might one to check out.