meeDamian/tag-suggestions

Github Action to, based on git tags, generate convenience Docker tags.

Human language

In other words, this action suggests you what extra tags to create for Docker Hub upon new version-tag creation. For example, given existing tags: v1.0.0, v1.0.1, v1.1.0, and new tag being added: v1.0.2 this action would recommend the creation of v1.0, but not :latest (as a tag with higher version exists), nor :v1 (as a newer tag with the same major version exists).

Usage

See action.yml

Example usage

on:
  push:
    tags: [ '*' ]
…

steps:
- uses: actions/checkout@v1

- uses: meeDamian/tag-suggestions@1.0
  id: tags

- name: Print all recommended versions
  run: |
    echo "latest: ${{ steps.tags.outputs.latest }}"
    echo "major:  ${{ steps.tags.outputs.major }}"
    echo "minor:  ${{ steps.tags.outputs.minor }}"

- name: Tag minor version, if recommended
  run: |
    # convert to lowercase
    REPO="${GITHUB_REPOSITORY,,}"

    # extract tag from `$GITHUB_REF`.  Only works if workflow triggered by tag push.
    VERSION="${GITHUB_REF#refs/tags/}"

    if [ -n "${{ steps.tags.outputs.minor }}" ]; then
      NEW_TAG="$REPO:${{ steps.tags.outputs.minor }}"

      docker tag  "$REPO:$VERSION"  "$NEW_TAG"
      docker push "$NEW_TAG"
    fi

Arguments

name	required	description
`tag`	sometimes	Git tag to base suggestions on. If not provided, an extraction from `${GITHUB_REF}` is attempted (AKA not needed on git tag push).

Outputs

For a tag: vX.Y.Z

name	value	description
`latest`	`latest`	Only set if `:latest` tag creation is recommended.
`major`	`vX`	Only set if major tag creation is recommended.
`minor`	`vX.Y`	Only set if minor tag creation is recommended.

Versioning

As of Sep 2019, Github Actions doesn't natively understand shortened tags in uses: directive.

To go around that and not do what git-tag-manual calls "The insane thing", I'm creating permanent git tags for each release in a semver format prefixed with v, as well as maintain branches with shortened tags. You can see the exact process here.

Ex. 1.0 branch always points to the newest v1.0.x tag.

In practice:

# For exact version
steps:
  uses: meeDamian/tag-suggestions@v1.0.1

# For newest minor version 1.0
steps:
  uses: meeDamian/tag-suggestions@1.0

Note: It's likely branches will be deprecated once Github Actions fixes its limitation.

License

The scripts and documentation in this project are released under the MIT License