metadata-action/README.md

About

GitHub Action to extract metadata (tags, labels) for Docker. This action is particularly useful if used with Docker Build Push action.

If you are interested, check out my other :octocat: GitHub Actions!

---

• Usage
  • Basic
  • Semver
  • Bake definition
• Customizing
  • inputs
  • outputs
• Notes
  • Latest tag
  • Handle semver tag
  • tag-match examples
  • Schedule tag
  • Overwrite labels
• Keep up-to-date with GitHub Dependabot
• Contributing
• License

Usage

Basic

Event	Ref	Commit SHA	Docker Tags
pull_request	refs/pull/2/merge	a123b57	pr-2
push	refs/heads/master	cf20257	master
push	refs/heads/my/branch	a5df687	my-branch
push tag	refs/tags/v1.2.3	ad132f5	v1.2.3, latest
push tag	refs/tags/v2.0.8-beta.67	fc89efd	v2.0.8-beta.67, latest

name: ci

on:
  push:
    branches:
      - '**'
    tags:
      - 'v*'
  pull_request:

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      -
        name: Checkout
        uses: actions/checkout@v2
      -
        name: Docker meta
        id: docker_meta
        uses: crazy-max/ghaction-docker-meta@v1
        with:
          images: name/app
      -
        name: Set up QEMU
        uses: docker/setup-qemu-action@v1
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
      -
        name: Login to DockerHub
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      -
        name: Build and push
        uses: docker/build-push-action@v2
        with:
          context: .
          file: ./Dockerfile
          platforms: linux/amd64,linux/arm64,linux/386
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.docker_meta.outputs.tags }}
          labels: ${{ steps.docker_meta.outputs.labels }}

Semver

Event	Ref	Commit SHA	Docker Tags
pull_request	refs/pull/2/merge	a123b57	pr-2
push	refs/heads/master	cf20257	master
push	refs/heads/my/branch	a5df687	my-branch
push tag	refs/tags/v1.2.3	ad132f5	1.2.3, 1.2, latest
push tag	refs/tags/v2.0.8-beta.67	fc89efd	2.0.8-beta.67

name: ci

on:
  push:
    branches:
      - '**'
    tags:
      - 'v*'
  pull_request:

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      -
        name: Checkout
        uses: actions/checkout@v2
      -
        name: Docker meta
        id: docker_meta
        uses: crazy-max/ghaction-docker-meta@v1
        with:
          images: name/app
          tag-semver: |
            {{version}}
            {{major}}.{{minor}}            
      -
        name: Set up QEMU
        uses: docker/setup-qemu-action@v1
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
      -
        name: Login to DockerHub
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      -
        name: Build and push
        uses: docker/build-push-action@v2
        with:
          context: .
          file: ./Dockerfile
          platforms: linux/amd64,linux/arm64,linux/386
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.docker_meta.outputs.tags }}
          labels: ${{ steps.docker_meta.outputs.labels }}

Bake definition

This action also handles a bake definition file that can be used with the Docker Buildx Bake action. You just have to declare an empty target named ghaction-docker-meta and inherit from it.

// docker-bake.hcl

target "ghaction-docker-meta" {}

target "build" {
  inherits = ["ghaction-docker-meta"]
  context = "./"
  dockerfile = "Dockerfile"
  platforms = ["linux/amd64", "linux/arm/v6", "linux/arm/v7", "linux/arm64", "linux/386", "linux/ppc64le"]
}

name: ci

on:
  push:
    branches:
      - '**'
    tags:
      - 'v*'
  pull_request:

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      -
        name: Checkout
        uses: actions/checkout@v2
      -
        name: Docker meta
        id: docker_meta
        uses: crazy-max/ghaction-docker-meta@v1
        with:
          images: name/app
          tag-sha: true
          tag-semver: |
            {{version}}
            {{major}}.{{minor}}            
      -
        name: Set up QEMU
        uses: docker/setup-qemu-action@v1
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
      -
        name: Build
        uses: crazy-max/ghaction-docker-buildx-bake@v1
        with:
          files: |
            ./docker-bake.hcl
            ${{ steps.docker_meta.outputs.bake-file }}            
          targets: |
            build            

Content of ${{ steps.docker_meta.outputs.bake-file }} file will look like this:

{
  "target": {
    "ghaction-docker-meta": {
      "tags": [
        "name/app:1.1.1",
        "name/app:1.1",
        "name/app:latest"
      ],
      "labels": {
        "org.opencontainers.image.title": "Hello-World",
        "org.opencontainers.image.description": "This your first repo!",
        "org.opencontainers.image.url": "https://github.com/octocat/Hello-World",
        "org.opencontainers.image.source": "https://github.com/octocat/Hello-World",
        "org.opencontainers.image.version": "1.1.1",
        "org.opencontainers.image.created": "2020-01-10T00:30:00.000Z",
        "org.opencontainers.image.revision": "90dd6032fac8bda1b6c4436a2e65de27961ed071",
        "org.opencontainers.image.licenses": "MIT"
      },
      "args": {
        "DOCKER_META_IMAGES": "name/app",
        "DOCKER_META_VERSION": "1.1.1"
      }
    }
  }
}

Customizing

inputs

Following inputs can be used as step.with keys

List type is a newline-delimited string

label-custom: |
  org.opencontainers.image.title=MyCustomTitle
  org.opencontainers.image.description=Another description
  org.opencontainers.image.vendor=MyCompany  

CSV type is a comma-delimited string

images: name/app,ghcr.io/name/app

Name	Type	Description
images	List/CSV	List of Docker images to use as base name for tags
tag-sha	Bool	Add git short commit as Docker tag (default false)
tag-edge	Bool	Enable edge branch tagging (default false)
tag-edge-branch	String	Branch that will be tagged as edge (default repo.default_branch)
tag-semver	List/CSV	Handle Git tag as semver template if possible
tag-match	String	RegExp to match against a Git tag and use first match as Docker tag
tag-match-group	Number	Group to get if tag-match matches (default 0)
tag-latest	Bool	Set latest Docker tag if tag-semver, tag-match or Git tag event occurs (default true)
tag-schedule	String	Template to apply to schedule tag (default nightly)
tag-custom	List/CSV	List of custom tags
tag-custom-only	Bool	Only use tag-custom as Docker tags
label-custom	List	List of custom labels
sep-tags	String	Separator to use for tags output (default \n)
sep-labels	String	Separator to use for labels output (default \n)

tag-semver and tag-match are mutually exclusive

outputs

Following outputs are available

Name	Type	Description
version	String	Docker image version
tags	String	Docker tags
labels	String	Docker labels
bake-file	File	Bake definition file path

Notes

Latest tag

Latest Docker tag will be generated by default on push tag event. If for example you push the v1.2.3 Git tag, you will have at the output of this action the Docker tags v1.2.3 and latest. But you can allow the latest tag to be generated only if tag-semver is a valid semver or if Git tag matches a regular expression with the tag-match input. Can be disabled if tag-latest is false.

Handle semver tag

If Git tag is a valid semver you can handle it to output multi Docker tags at once. tag-semver supports multi-line Handlebars template with the following inputs:

Git tag	tag-semver	Valid	Output tags	Output version
v1.2.3	{{raw}}	✅	v1.2.3, latest	v1.2.3
v1.2.3	{{version}}	✅	1.2.3, latest	1.2.3
v1.2.3	{{major}}.{{minor}}	✅	1.2, latest	1.2
v1.2.3	v{{major}}	✅	v1, latest	v1
v1.2.3	{{minor}}	✅	2, latest	2
v1.2.3	{{patch}}	✅	3, latest	3
v1.2.3	{{major}}.{{minor}} {{major}}.{{minor}}.{{patch}}	✅	1.2, 1.2.3, latest	1.2*
v2.0.8-beta.67	{{raw}}	✅	2.0.8-beta.67**	2.0.8-beta.67
v2.0.8-beta.67	{{version}}	✅	2.0.8-beta.67	2.0.8-beta.67
v2.0.8-beta.67	{{major}}.{{minor}}	✅	2.0.8-beta.67**	2.0.8-beta.67
release1	{{raw}}	❌	release1	release1

*First occurrence of tag-semver will be taken as output.version

**Pre-release (rc, beta, alpha) will only extend {{version}} as tag because they are updated frequently, and contain many breaking changes that are (by the author's design) not yet fit for public consumption.

tag-match examples

Git tag	tag-match	tag-match-group	Match	Output tags	Output version
v1.2.3	\d{1,3}.\d{1,3}.\d{1,3}	0	✅	1.2.3, latest	1.2.3
v2.0.8-beta.67	v(.*)	1	✅	2.0.8-beta.67, latest	2.0.8-beta.67
v2.0.8-beta.67	v(\d.\d)	1	✅	2.0, latest	2.0
release1	\d{1,3}.\d{1,3}	0	❌	release1	release1
20200110-RC2	\d+	0	✅	20200110, latest	20200110

Schedule tag

tag-schedule is specially crafted input to support Handlebars template with the following expressions:

Expression	Example	Description
{{date 'format'}}	{{date 'YYYYMMDD'}} > 20200110	Render date by its moment format

You can find more examples in the CI workflow.

Overwrite labels

If some of the OCI Image Format Specification labels generated are not suitable, you can overwrite them like this:

      -
        name: Docker meta
        id: docker_meta
        uses: crazy-max/ghaction-docker-meta@v1
        with:
          images: name/app
          label-custom: |
            maintainer=CrazyMax
            org.opencontainers.image.title=MyCustomTitle
            org.opencontainers.image.description=Another description
            org.opencontainers.image.vendor=MyCompany            

Keep up-to-date with GitHub Dependabot

Since Dependabot has native GitHub Actions support, to enable it on your GitHub repo all you need to do is add the .github/dependabot.yml file:

version: 2
updates:
  # Maintain dependencies for GitHub Actions
  - package-ecosystem: "github-actions"
    directory: "/"
    schedule:
      interval: "daily"

Contributing

Want to contribute? Awesome! The most basic way to show your support is to star 🌟 the project, or to raise issues 💬. If you want to open a pull request, please read the contributing guidelines.

You can also support this project by becoming a sponsor on GitHub or by making a Paypal donation to ensure this journey continues indefinitely!

Thanks again for your support, it is much appreciated! 🙏

License

MIT. See LICENSE for more details.