Docker Extract

A GitHub Action for extracting files from a Docker Image.

- uses: shrink/actions-docker-extract@v3
  with:
    image: "ghost:alpine"
    path: "/var/lib/ghost/current/core/built/assets/."

Inputs

ID	Description	Required	Examples
image	Docker Image to extract files from	✅	alpine ghcr.io/github/super-linter:latest
path	Path (from root) to a file or directory within Image	✅	files/example.txt files files/.
destination	Destination path for the extracted files	❌	/foo/ ~/ ./foo/bar

📎 To copy the contents of a directory the path must end with /. otherwise the directory itself will be copied. More information about the specific rules can be found via the docker cp documentation.

Outputs

ID	Description	Example
destination	Destination path containing the extracted file(s)	.extracted-1598717412/

Examples

Build, Extract

Using docker/build-push-action to build a Docker Image and then extract the contents of the /app directory within the newly built image to upload as a dist artifact.

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Build Docker Image
        uses: docker/build-push-action@v5
        with:
          tags: my-example-image:latest
          load: true
      - uses: shrink/actions-docker-extract@v3
        id: extract
        with:
          image: my-example-image:latest
          path: /app/.
          destination: dist
      - name: Upload Dist
        uses: actions/upload-artifact@v3
        with:
          path: dist

Login, Pull, Extract

Using docker/login-action to authenticate with the GitHub Container Registry to extract from a published Docker Image.

jobs:
  extract:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Login to GitHub Container Registry
        uses: docker/login-action@v2
        with:
          registry: "ghcr.io"
          username: "${{ github.actor }}"
          password: "${{ secrets.GITHUB_TOKEN }}"
      - uses: shrink/actions-docker-extract@v3
        id: extract
        with:
          image: ghcr.io/${{ github.repository }}:latest
          path: /app/.
          destination: dist
      - name: Upload Dist
        uses: actions/upload-artifact@v3
        with:
          path: dist

Automatic Release Packaging

A Workflow packages the Action automatically when a collaborator created a new tag. Any reference to this Action in a Workflow must use a tag (mutable) or the commit hash of a tag (immutable).

✅ uses: shrink/actions-docker-extract@v3
✅ uses: shrink/actions-docker-extract@v3.0.0
✅ uses: shrink/actions-docker-extract@40400b42f4f8b663c647f535e2c6674658e39fc6
❌ uses: shrink/actions-docker-extract@main

The blog post Package GitHub Actions automatically with GitHub Actions describes how this is achieved.