This Action for Docker uses the Git branch as the Docker tag for building and pushing the container. Hereby the master-branch is published as the latest-tag.

name: Publish Docker
on: [push]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@master
    - name: Publish to Registry
      uses: elgohr/Publish-Docker-Github-Action@master
      with:
        name: myDocker/repository
        username: ${{ secrets.DOCKER_USERNAME }}
        password: ${{ secrets.DOCKER_PASSWORD }}

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

If you would like to publish the image to AWS ECR, please have a look at https://github.com/elgohr/ecr-login-action

tag is the tag, which was pushed
snapshot-tag is the tag that is generated by the snapshot-option and pushed

Use registry for pushing to a custom registry

with:
  name: myDocker/repository
  username: ${{ secrets.DOCKER_USERNAME }}
  password: ${{ secrets.DOCKER_PASSWORD }}
  registry: docker.pkg.github.com

Use snapshot to push an additional image, which is tagged with
{YEAR}{MONTH}{DAY}{HOUR}{MINUTE}{SECOND}{first 6 digits of the git sha}.
The date was inserted to prevent new builds with external dependencies override older builds with the same sha. When you would like to think about versioning images, this might be useful.

with:
  name: myDocker/repository
  username: ${{ secrets.DOCKER_USERNAME }}
  password: ${{ secrets.DOCKER_PASSWORD }}
  snapshot: true

Use dockerfile when you would like to explicitly build a Dockerfile.
This might be useful when you have multiple DockerImages.

with:
  name: myDocker/repository
  username: ${{ secrets.DOCKER_USERNAME }}
  password: ${{ secrets.DOCKER_PASSWORD }}
  dockerfile: MyDockerFileName

Use workdir when you would like to change the directory for building.

with:
  name: myDocker/repository
  username: ${{ secrets.DOCKER_USERNAME }}
  password: ${{ secrets.DOCKER_PASSWORD }}
  workdir: mySubDirectory

Use buildargs when you want to pass a list of environment variables as build-args. Identifiers are separated by comma.
All buildargs will be masked, so that they don't appear in the logs.

- name: Publish to Registry
  uses: elgohr/Publish-Docker-Github-Action@master
  env:
    MY_FIRST: variableContent
    MY_SECOND: variableContent
  with:
    name: myDocker/repository
    username: ${{ secrets.DOCKER_USERNAME }}
    password: ${{ secrets.DOCKER_PASSWORD }}
    buildargs: MY_FIRST,MY_SECOND

Use cache when you have big images, that you would only like to build partially (changed layers).

CAUTION: This will cache the non changed parts forever. If you use this option, make sure that these parts will be updated by another job!

with:
  name: myDocker/repository
  username: ${{ secrets.DOCKER_USERNAME }}
  password: ${{ secrets.DOCKER_PASSWORD }}
  cache: true