✨ Extract path from Docker Image (#1)

README.md

@@ -0,0 +1,80 @@
+# Docker Extract
+
+A GitHub Action for extracting files from a Docker Image.
+
+```yaml
+- uses: shrink/actions-docker-extract@v1
+  with:
+    image: 'docker.pkg.github.com/github/semantic/semantic'
+    path: '/etc/motd'
+```
+
+## Inputs
+
+All inputs are required.
+
+| ID  | Description | Example |
+| --- | ----------- | ------- |
+| `image` | Docker Image to extract files from | `alpine` |
+| `path` | Path (from root) to a file or directory within Image | `/etc/motd` |
+
+## 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
+        with:
+          image: my-example-image
+          path: /app
+      - name: Upload Dist
+        uses: actions/upload-artifact@v2
+        with:
+          path: ${{ steps.extract.outputs.destination }}/app
+          name: dist
+```
+
+### Login, Pull, Extract
+
+Using [docker/login-action][login-action] to authenticate with the GitHub
+Package Registry to extract from a published Docker Image.
+
+```yaml
+jobs:
+  extract:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Login to GitHub Package Registry
+        uses: docker/login-action@v1
+        with:
+          registry: docker.pkg.github.com
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - uses: shrink/actions-docker-extract@v1
+        with:
+          image: ${{ github.repository }}/example-image:latest
+          path: /app
+      - name: Upload Dist
+        uses: actions/upload-artifact@v2
+        with:
+          path: ${{ steps.extract.outputs.destination }}/app
+          name: dist
+```
+
+[build-push-action]: https://github.com/docker/build-push-action
+[login-action]: https://github.com/docker/login-action