Allow specifying the Dockerfile path (#29)

Author: omus

README.md

@@ -48,6 +48,7 @@ jobs:
 |:---------------------|:------------|:---------|:--------|
 | `image-repository`   | The Docker image repository to push the build image and cached layers. | Yes | `temporary/my-image` |
 | `context`            | The Docker build context directory. Defaults to `.`. | No | `./my-image` |
+| `dockerfile`         | Path to the Dockerfile relative to the [`working-directory`](https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsworking-directory). Defaults to `${context}/Dockerfile`. | No | `./my-image.Dockerfile` |
 | `build-args`         | List of [build-time variables](https://docs.docker.com/reference/cli/docker/buildx/build/#build-arg). | No | <pre><code>HTTP_PROXY=http://10.20.30.2:1234 &#10;FTP_PROXY=http://40.50.60.5:4567</code></pre> |
 | `build-secrets`      | List of [secrets](https://docs.docker.com/engine/reference/commandline/buildx_build/#secret) to expose to the build. | No | <pre><code>GIT_AUTH_TOKEN=mytoken</code></pre> |
 | `from-scratch`       | Do not read from the cache when building the image. Writes to caches will still occur. Defaults to `false`. | No | `false` |

action.yaml

@@ -11,6 +11,11 @@ inputs:
   context:
     description: The Docker build context directory.
     default: "."
+  dockerfile:
+    description: >-
+      Path to the Dockerfile relative to the `working-directory`. Defaults to
+      `${context}/Dockerfile`.
+    default: ""
   build-args:
     description: List of build-time variables.
     required: false
@@ -191,8 +196,9 @@ runs:
       id: build-push
       uses: docker/build-push-action@471d1dc4e07e5cdedd4c2171150001c434f0b7a4 # v6.15.0
       with:
-        context: ${{ inputs.context }}
         builder: ${{ steps.builder.outputs.name }}
+        context: ${{ inputs.context }}
+        file: ${{ inputs.dockerfile }}
         build-args: ${{ inputs.build-args }}
         secrets: ${{ inputs.build-secrets }}
         cache-from: ${{ steps.cache.outputs.from-tags }}