Add Layers input for build using dockerfile (#43)

Also add link to buildah docs in the README

Signed-off-by: divyansh42 <diagrawa@redhat.com>

.github/workflows/dockerfile_build.yml

@@ -31,6 +31,7 @@ jobs:
         uses: ./buildah-build/
         with:
           image: ${{ env.IMAGE_NAME }}
+          layers: false
           tags: 'latest ${{ github.sha }}'
           dockerfiles: |
             ./Dockerfile

README.md

@@ -9,9 +9,9 @@
 [![license badge](https://img.shields.io/github/license/redhat-actions/buildah-build)](./LICENSE)
 [![size badge](https://img.shields.io/github/size/redhat-actions/buildah-build/dist/index.js)](./dist)
 
-Buildah is a GitHub Action for building Docker and Kubernetes-compatible images quickly and easily.
+Buildah Build is a GitHub Action for building Docker and Kubernetes-compatible images quickly and easily.
 
-Buildah only works on Linux. GitHub's [Ubuntu Environments](https://github.com/actions/virtual-environments#available-environments) (`ubuntu-18.04` and newer) come with buildah installed. If you are not using these environments, or if you want to use a different version, you must first [install buildah](https://github.com/containers/buildah/blob/master/install.md).
+[Buildah](https://github.com/containers/buildah/tree/master/docs) only works on Linux. GitHub's [Ubuntu Environments](https://github.com/actions/virtual-environments#available-environments) (`ubuntu-18.04` and newer) come with buildah installed. If you are not using these environments, or if you want to use a different version, you must first [install buildah](https://github.com/containers/buildah/blob/master/install.md).
 
 After building your image, use [push-to-registry](https://github.com/redhat-actions/push-to-registry) to push the image and make it pullable.
 
@@ -21,7 +21,7 @@ After building your image, use [push-to-registry](https://github.com/redhat-acti
 
 <a id="dockerfile-build-inputs"></a>
 
-### Inputs for build from dockerfile
+### [Inputs for build from dockerfile](https://github.com/containers/buildah/blob/master/docs/buildah-bud.md)
 
 | Input Name | Description | Default |
 | ---------- | ----------- | ------- |
@@ -30,12 +30,13 @@ After building your image, use [push-to-registry](https://github.com/redhat-acti
 | context | Path to directory to use as the build context. | `.`
 | dockerfiles | The list of Dockerfile paths to perform a build using docker instructions. This is a multiline input to allow multiple Dockerfiles. | **Must be provided**
 | image | Name to give to the output image. | **Must be provided**
+| layers | Set to true to cache intermediate layers during the build process. | None
 | oci | Build the image using the OCI format, instead of the Docker format. By default, this is `false`, because images built using the OCI format have issues when published to Dockerhub. | `false`
 | tags | The tags of the image to build. For multiple tags, separate by a space. For example, `latest ${{ github.sha }}` | `latest`
 
 <a id="scratch-build-inputs"></a>
 
-### Inputs for build without dockerfile
+### [Inputs for build without dockerfile](https://github.com/containers/buildah/blob/master/docs/buildah-config.md)
 
 | Input Name | Description | Default |
 | ---------- | ----------- | ------- |

action.yml

@@ -28,6 +28,9 @@ inputs:
   entrypoint:
     description: 'The entry point to set for containers based on image'
     required: false
+  layers:
+    description: 'Set to true to cache intermediate layers during build process'
+    required: false
   port:
     description: 'The port to expose when running containers based on image'
     required: false

src/buildah.ts

@@ -13,7 +13,8 @@ export interface BuildahConfigSettings {
 
 interface Buildah {
     buildUsingDocker(
-        image: string, context: string, dockerFiles: string[], buildArgs: string[], useOCI: boolean, archs: string,
+        image: string, context: string, dockerFiles: string[], buildArgs: string[],
+        useOCI: boolean, archs: string, layers: string
     ): Promise<CommandResult>;
     from(baseImage: string): Promise<CommandResult>;
     copy(container: string, contentToCopy: string[]): Promise<CommandResult | undefined>;
@@ -33,7 +34,8 @@ export class BuildahCli implements Buildah {
     }
 
     async buildUsingDocker(
-        image: string, context: string, dockerFiles: string[], buildArgs: string[], useOCI: boolean, archs: string
+        image: string, context: string, dockerFiles: string[], buildArgs: string[],
+        useOCI: boolean, archs: string, layers: string
     ): Promise<CommandResult> {
         const args: string[] = [ "bud" ];
         if (archs) {
@@ -49,6 +51,9 @@ export class BuildahCli implements Buildah {
             args.push(buildArg);
         });
         args.push(...BuildahCli.getImageFormatOption(useOCI));
+        if (layers) {
+            args.push(`--layers=${layers}`);
+        }
         args.push("-t");
         args.push(image);
         args.push(context);

src/generated/inputs-outputs.ts

@@ -55,6 +55,12 @@ export enum Inputs {
      * Default: None.
      */
     IMAGE = "image",
+    /**
+     * Set to true to cache intermediate layers during build process
+     * Required: false
+     * Default: None.
+     */
+    LAYERS = "layers",
     /**
      * Set to true to build using the OCI image format instead of the Docker image format
      * Required: false

src/index.ts

@@ -61,7 +61,8 @@ async function doBuildUsingDockerFiles(
     const context = path.join(workspace, core.getInput(Inputs.CONTEXT));
     const buildArgs = getInputList(Inputs.BUILD_ARGS);
     const dockerFileAbsPaths = dockerFiles.map((file) => path.join(workspace, file));
-    await cli.buildUsingDocker(newImage, context, dockerFileAbsPaths, buildArgs, useOCI, archs);
+    const layers = core.getInput(Inputs.LAYERS);
+    await cli.buildUsingDocker(newImage, context, dockerFileAbsPaths, buildArgs, useOCI, archs, layers);
 }
 
 async function doBuildFromScratch(