Add support for 'platform' parameter (#75)

Signed-off-by: James Addison <jay@jp-hosting.net>

.github/workflows/multiarch.yml

@@ -11,8 +11,8 @@ env:
   IMAGE_TAG: latest
 
 jobs:
-  build:
-    name: Build image using Buildah
+  build-multiarch:
+    name: Build multi-architecture image using Buildah
     runs-on: ubuntu-20.04
     strategy:
       fail-fast: false
@@ -51,7 +51,7 @@ jobs:
           EOF
 
       - name: Build Image
-        id: build_image
+        id: build_image_multiarch
         uses: ./buildah-build/
         with:
           image: ${{ env.IMAGE_NAME }}
@@ -63,9 +63,9 @@ jobs:
 
       - name: Echo Outputs
         run: |
-          echo "Image: ${{ steps.build_image.outputs.image }}"
-          echo "Tags: ${{ steps.build_image.outputs.tags }}"
-          echo "Tagged Image: ${{ steps.build_image.outputs.image-with-tag }}"
+          echo "Image: ${{ steps.build_image_multiarch.outputs.image }}"
+          echo "Tags: ${{ steps.build_image_multiarch.outputs.tags }}"
+          echo "Tagged Image: ${{ steps.build_image_multiarch.outputs.image-with-tag }}"
 
       - name: Check images created
         run: buildah images | grep '${{ env.IMAGE_NAME }}'
@@ -73,9 +73,76 @@ jobs:
       - name: Check image metadata
         run: |
           set -x
-          buildah inspect ${{ steps.build_image.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".OCIv1.architecture"
-          buildah inspect ${{ steps.build_image.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".Docker.architecture"
+          buildah inspect ${{ steps.build_image_multiarch.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".OCIv1.architecture"
+          buildah inspect ${{ steps.build_image_multiarch.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".Docker.architecture"
 
       - name: Run image
         run: |
-          podman run --rm ${{ steps.build_image.outputs.image }}:${{ env.IMAGE_TAG }}
+          podman run --rm ${{ steps.build_image_multiarch.outputs.image }}:${{ env.IMAGE_TAG }}
+
+  build-multiplatform:
+    name: Build multi-platform image using Buildah
+    runs-on: ubuntu-20.04
+    strategy:
+      fail-fast: false
+      matrix:
+        platform: [ "linux/amd64", "linux/arm64/v8" ]
+        install_latest: [ true, false ]
+
+    steps:
+
+      # Checkout buildah action github repository
+      - name: Checkout Buildah action
+        uses: actions/checkout@v2
+        with:
+          path: "buildah-build"
+
+      - name: Install latest buildah
+        if: matrix.install_latest
+        run: |
+          bash buildah-build/.github/install_latest_buildah.sh
+
+      - name: Install qemu dependency
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y qemu-user-static
+
+      - name: Create Containerfile
+        run: |
+          cat > Containerfile<<EOF
+
+          FROM docker.io/alpine:3.14
+
+          RUN echo "hello world"
+
+          ENTRYPOINT [ "sh", "-c", "echo -n 'Machine: ' && uname -m && echo -n 'Bits: ' && getconf LONG_BIT && echo 'goodbye world'" ]
+          EOF
+
+      - name: Build Image
+        id: build_image_multiplatform
+        uses: ./buildah-build/
+        with:
+          image: ${{ env.IMAGE_NAME }}
+          tags: ${{ env.IMAGE_TAG }}
+          platform: ${{ matrix.platform }}
+          containerfiles: |
+            ./Containerfile
+
+      - name: Echo Outputs
+        run: |
+          echo "Image: ${{ steps.build_image_multiplatform.outputs.image }}"
+          echo "Tags: ${{ steps.build_image_multiplatform.outputs.tags }}"
+          echo "Tagged Image: ${{ steps.build_image_multiplatform.outputs.image-with-tag }}"
+
+      - name: Check images created
+        run: buildah images | grep '${{ env.IMAGE_NAME }}'
+
+      - name: Check image metadata
+        run: |
+          set -x
+          buildah inspect ${{ steps.build_image_multiplatform.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".OCIv1.architecture"
+          buildah inspect ${{ steps.build_image_multiplatform.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".Docker.architecture"
+
+      - name: Run image
+        run: |
+          podman run --rm ${{ steps.build_image_multiplatform.outputs.image }}:${{ env.IMAGE_TAG }}

README.md

@@ -26,6 +26,7 @@ After building your image, use [push-to-registry](https://github.com/redhat-acti
 | Input Name | Description | Default |
 | ---------- | ----------- | ------- |
 | arch | Label the image with this architecture, instead of defaulting to the host architecture. Refer to [Multi arch builds](#multi-arch-builds) for more information. | None (host architecture)
+| platform | Label the image with this platform, instead of defaulting to the host platform. Refer to [Multi arch builds](#multi-arch-builds) for more information. | None (host platform)
 | build-args | Build arguments to pass to the Docker build using `--build-arg`, if using a Containerfile that requires ARGs. Use the form `arg_name=arg_value`, and separate arguments with newlines. | None
 | context | Path to directory to use as the build context. | `.`
 | containerfiles\* | The list of Containerfile paths to perform a build using docker instructions. This is a multiline input to allow multiple Containerfiles. | **Must be provided**
@@ -43,6 +44,7 @@ After building your image, use [push-to-registry](https://github.com/redhat-acti
 | Input Name | Description | Default |
 | ---------- | ----------- | ------- |
 | arch | Label the image with this architecture, instead of defaulting to the host architecture. Refer to [Multi arch builds](#multi-arch-builds) for more information. | None (host architecture)
+| platform | Label the image with this platform, instead of defaulting to the host platform. Refer to [Multi arch builds](#multi-arch-builds) for more information. | None (host platform)
 | base-image | The base image to use for the container. | **Must be provided**
 | content | Paths to files or directories to copy inside the container to create the file image. This is a multiline input to allow you to copy multiple files/directories.| None
 | entrypoint | The entry point to set for the container. This is a multiline input; split arguments across lines. | None
@@ -179,8 +181,8 @@ sudo podman run --rm --privileged docker.io/tonistiigi/binfmt --install all
 ```
 This registration remains active until the host reboots.
 
-### The `arch` input
-The `arch` argument overrides the Architecture label in the output image. It does not actually affect the architectures the output image will run on. The image must still be built for the required architecture.
+### The `arch` and `platform` inputs
+The `arch` and `platform` arguments override the Architecture and Platform labels in the output image, respectively. They do not actually affect the architectures and platforms the output image will run on. The image must still be built for the required architecture or platform.
 
 There is a simple example [in this issue](https://github.com/redhat-actions/buildah-build/issues/60#issuecomment-876552452).
 

action.yml

@@ -56,6 +56,9 @@ inputs:
   archs:
     description: 'Alias for "arch". "arch" takes precedence if both are set.'
     required: false
+  platform:
+    description: 'Label the image with this PLATFORM, instead of defaulting to the host platform.'
+    required: false
   extra-args:
     description: |
       Extra args to be passed to buildah bud.

src/buildah.ts

@@ -15,12 +15,13 @@ export interface BuildahConfigSettings {
     port?: string;
     workingdir?: string;
     arch?: string;
+    platform?: string;
 }
 
 interface Buildah {
     buildUsingDocker(
         image: string, context: string, containerFiles: string[], buildArgs: string[],
-        useOCI: boolean, arch: string, layers: string, extraArgs: string[]
+        useOCI: boolean, arch: string, platform: string, layers: string, extraArgs: string[]
     ): Promise<CommandResult>;
     from(baseImage: string): Promise<CommandResult>;
     config(container: string, setting: BuildahConfigSettings): Promise<CommandResult>;
@@ -63,13 +64,17 @@ export class BuildahCli implements Buildah {
 
     async buildUsingDocker(
         image: string, context: string, containerFiles: string[], buildArgs: string[],
-        useOCI: boolean, arch: string, layers: string, extraArgs: string[]
+        useOCI: boolean, arch: string, platform: string, layers: string, extraArgs: string[]
     ): Promise<CommandResult> {
         const args: string[] = [ "bud" ];
         if (arch) {
             args.push("--arch");
             args.push(arch);
         }
+        if (platform) {
+            args.push("--platform");
+            args.push(platform);
+        }
         containerFiles.forEach((file) => {
             args.push("-f");
             args.push(file);
@@ -135,6 +140,10 @@ export class BuildahCli implements Buildah {
             args.push("--arch");
             args.push(settings.arch);
         }
+        if (settings.platform) {
+            args.push("--platform");
+            args.push(settings.platform);
+        }
         if (settings.workingdir) {
             args.push("--workingdir");
             args.push(settings.workingdir);

src/generated/inputs-outputs.ts

@@ -85,6 +85,12 @@ export enum Inputs {
      * Default: "false"
      */
     OCI = "oci",
+    /**
+     * Label the image with this PLATFORM, instead of defaulting to the host platform.
+     * Required: false
+     * Default: None.
+     */
+    PLATFORM = "platform",
     /**
      * The port to expose when running containers based on image
      * Required: false

src/index.ts

@@ -9,7 +9,7 @@ import * as path from "path";
 import { Inputs, Outputs } from "./generated/inputs-outputs";
 import { BuildahCli, BuildahConfigSettings } from "./buildah";
 import {
-    getArch, getContainerfiles, getInputList, splitByNewline,
+    getArch, getPlatform, getContainerfiles, getInputList, splitByNewline,
     isFullImageName, getFullImageName,
 } from "./utils";
 
@@ -54,12 +54,17 @@ export async function run(): Promise<void> {
     const useOCI = core.getInput(Inputs.OCI) === "true";
 
     const arch = getArch();
+    const platform = getPlatform();
+
+    if (arch && platform) {
+        throw new Error("The --platform option may not be used in combination with the --arch option.");
+    }
 
     if (containerFiles.length !== 0) {
-        await doBuildUsingContainerFiles(cli, newImage, workspace, containerFiles, useOCI, arch);
+        await doBuildUsingContainerFiles(cli, newImage, workspace, containerFiles, useOCI, arch, platform);
     }
     else {
-        await doBuildFromScratch(cli, newImage, useOCI, arch);
+        await doBuildFromScratch(cli, newImage, useOCI, arch, platform);
     }
 
     if (tagsList.length > 1) {
@@ -71,7 +76,8 @@ export async function run(): Promise<void> {
 }
 
 async function doBuildUsingContainerFiles(
-    cli: BuildahCli, newImage: string, workspace: string, containerFiles: string[], useOCI: boolean, arch: string
+    cli: BuildahCli, newImage: string, workspace: string, containerFiles: string[], useOCI: boolean, arch: string,
+    platform: string
 ): Promise<void> {
     if (containerFiles.length === 1) {
         core.info(`Performing build from Containerfile`);
@@ -94,12 +100,12 @@ async function doBuildUsingContainerFiles(
         buildahBudExtraArgs = lines.flatMap((line) => line.split(" ")).map((arg) => arg.trim());
     }
     await cli.buildUsingDocker(
-        newImage, context, containerFileAbsPaths, buildArgs, useOCI, arch, layers, buildahBudExtraArgs
+        newImage, context, containerFileAbsPaths, buildArgs, useOCI, arch, platform, layers, buildahBudExtraArgs
     );
 }
 
 async function doBuildFromScratch(
-    cli: BuildahCli, newImage: string, useOCI: boolean, arch: string
+    cli: BuildahCli, newImage: string, useOCI: boolean, arch: string, platform: string
 ): Promise<void> {
     core.info(`Performing build from scratch`);
 
@@ -119,6 +125,7 @@ async function doBuildFromScratch(
         workingdir: workingDir,
         envs,
         arch,
+        platform,
     };
     await cli.config(containerId, newImageConfig);
     await cli.copy(containerId, content);

src/utils.ts

@@ -81,6 +81,10 @@ export function getArch(): string {
     return arch || archs;
 }
 
+export function getPlatform(): string {
+    return core.getInput(Inputs.PLATFORM);
+}
+
 export function getContainerfiles(): string[] {
     // 'containerfile' should be used over 'dockerfile',
     // see https://github.com/redhat-actions/buildah-build/issues/57