actions-docker-extract/README.md

# Docker Extract

A GitHub Action for extracting files from a Docker Image.

```yaml
- uses: shrink/actions-docker-extract@v1
  with:
    image: "ghost:alpine"
    path: "/var/lib/ghost/current/core/built/assets/."
```

## Inputs

All inputs are required.

| ID      | Description                                          | 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/.`         |

> :paperclip: 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][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][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.

```yaml
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Build Docker Image
        uses: docker/build-push-action@v1
        with:
          repository: my-example-image
          tags: latest
      - uses: shrink/actions-docker-extract@v1
        id: extract
        with:
          image: my-example-image
          path: /app/.
      - name: Upload Dist
        uses: actions/upload-artifact@v2
        with:
          path: ${{ steps.extract.outputs.destination }}
          name: dist
```

### Login, Pull, Extract

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

```yaml
jobs:
  extract:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Login to GitHub Container Registry
        uses: docker/login-action@v1
        with:
          registry: ghcr.io
          username: ${{ github.repository_owner }}
          password: ${{ secrets.GHCR_PAT }}
      - uses: shrink/actions-docker-extract@v1
        id: extract
        with:
          image: ghcr.io/${{ github.repository }}:latest
          path: /app/.
      - name: Upload Dist
        uses: actions/upload-artifact@v2
        with:
          path: ${{ steps.extract.outputs.destination }}
          name: 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][tags] (mutable)
or the commit hash of a tag (immutable).

```yaml
✅ uses: shrink/actions-docker-extract@v2
✅ uses: shrink/actions-docker-extract@v2.0.0
✅ uses: shrink/actions-docker-extract@abde1147dd0d248b38feda9e75768c3d2b57eefc
❌ uses: shrink/actions-docker-extract@main
```

The blog post
[Package GitHub Actions automatically with GitHub Actions][blog/package-automatically]
describes how this is achieved.

[build-push-action]: https://github.com/docker/build-push-action
[login-action]: https://github.com/docker/login-action
[docker-cp]: https://docs.docker.com/engine/reference/commandline/cp/#extended-description
[tags]: https://github.com/shrink/actions-docker-extract/tags
[blog/package-automatically]: https://medium.com/prompt/package-github-actions-automatically-with-github-actions-a70b9f7bae4