Merge pull request #35 from docker/add-cache-from

Add cache_froms input to support --cache-from

LICENSE

@@ -188,4 +188,4 @@
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
-   limitations under the License.
+   limitations under the License.

README.md

@@ -17,6 +17,7 @@ Suggestions and issues can be posted on the repositories [issues page](https://g
 * [target](#target)
 * [always_pull](#always_pull)
 * [build_args](#build_args)
+* [cache_froms](#cache_froms)
 * [labels](#labels)
 * [add_git_labels](#add_git_labels)
 * [push](#push)
@@ -86,11 +87,13 @@ Example:
 
 ### `path`
 
-Path to run the docker build from. Defaults to `.`.
+Path to the build context. Defaults to `.`
 
 ### `dockerfile`
 
-Name of the Dockerfile. Defaults to `{path}/Dockerfile`.
+Path to the Dockerfile. Defaults to `{path}/Dockerfile`
+
+Note when set this path is **not** relative to the `path` input but is instead relative to the current working directory.
 
 ### `target`
 
@@ -112,6 +115,15 @@ Example:
 build_args: arg1=value1,arg2=value2
 ```
 
+### `cache_froms`
+
+Comma-delimited list of images to consider as cache sources.
+
+Example:
+```yaml
+cache_froms: myorg/baseimage:latest
+```
+
 ### `labels`
 
 Comma-delimited list of labels to add to the built image.
@@ -190,4 +202,16 @@ with:
   repository: myorg/myrepository
   tag_with_ref: true
   target: mytarget
-```
+```
+
+The following will build the root Dockerfile, tag the image as `myorg/myrepository:latest`, log in to Google Container Registry using GitHub secrets (where `DOCKER_PASSWORD` is a [JSON key](https://cloud.google.com/container-registry/docs/advanced-authentication#json-key)), and push the image to the CGR repository `myorg/myrepository`:
+ 
+```yaml
+uses: docker/build-push-action@v1
+with:
+  username: _json_key
+  password: ${{ secrets.DOCKER_PASSWORD }}
+  registry: gcr.io
+  repository: myorg/myrepository
+  tags: latest
+```

action.yml

@@ -6,7 +6,7 @@ branding:
   color: 'blue'
 runs:
   using: docker
-  image: docker://docker/github-actions:v1.0
+  image: docker://docker/github-actions:v1
   args:
     - build-push
 inputs:
@@ -34,11 +34,11 @@ inputs:
     required: false
     default: false
   path:
-    description: Path to run docker build from
+    description: Path to the build context
     required: false
     default: "."
   dockerfile:
-    description: Name of the Dockerfile (Default is 'path/Dockerfile')
+    description: Path to the Dockerfile (Default is '{path}/Dockerfile')
     required: false
   target:
     description: Sets the target stage to build
@@ -50,6 +50,9 @@ inputs:
   build_args:
     description: Comma-delimited list of build-time variables
     required: false
+  cache_froms:
+    description: Comma-delimited list of images to consider as cache sources
+    required: false
   labels:
     description: Comma-delimited list of labels to add to the built image
     required: false