Add build-args input

Signed-off-by: Tim Etchells <tetchell@redhat.com>

README.md

@@ -58,6 +58,13 @@ After building your image, use [push-to-registry](https://github.com/redhat-acti
     Default: <code>.</code></td>
   </tr>
 
+  <tr>
+    <td>build-args</td>
+    <td>No</td>
+    <td>Build arguments to pass to the Docker build using <code>--build-arg</code>, if using a Dockerfile that requires ARGs.<br>
+    Uses the form <code>arg_name=arg_value</code>, and separate arguments with newlines.</td>
+  </tr>
+
   <tr>
     <td>content</td>
     <td>No</td>
@@ -109,7 +116,7 @@ You can configure the `buildah` action to build your image using one or more Doc
 
 If you have been using Docker and have an existing Dockerfile, `buildah` can reuse your dockerfile.
 
-In this case the inputs needed are `image` and `dockerfiles`. `tag` is also recommended.
+In this case the inputs needed are `image` and `dockerfiles`. `tag` is also recommended. If your Dockerfile requires ARGs, these can be passed using `build-arg`.
 
 ```yaml
 name: Build Image using Dockerfile
@@ -130,6 +137,8 @@ jobs:
         tag: v1
         dockerfiles: |
           ./Dockerfile
+        build-args: |
+          some_arg=some_value
 ```
 
 ### Building from scratch

action.yml

@@ -37,6 +37,9 @@ inputs:
   envs:
     description: 'List of environment variables to be set when running containers based on image'
     required: false
+  build-args:
+    description: 'List of --build-args to pass to buildah.'
+    required: false
 runs:
   using: 'node12'
   main: 'dist/index.js'

src/buildah.ts

@@ -3,7 +3,7 @@ import * as exec from "@actions/exec";
 import { CommandResult } from "./types";
 
 interface Buildah {
-    buildUsingDocker(image: string, context: string, dockerFiles: string[]): Promise<CommandResult>;
+    buildUsingDocker(image: string, context: string, dockerFiles: string[], buildArgs: string[]): Promise<CommandResult>;
     from(baseImage: string): Promise<CommandResult>;
     copy(container: string, contentToCopy: string[]): Promise<CommandResult>;
     config(container: string, setting: {}): Promise<CommandResult>;
@@ -25,12 +25,16 @@ export class BuildahCli implements Buildah {
         this.executable = executable;
     }
 
-    async buildUsingDocker(image: string, context: string, dockerFiles: string[]): Promise<CommandResult> {
+    async buildUsingDocker(image: string, context: string, dockerFiles: string[], buildArgs: string[]): Promise<CommandResult> {
         const args: string[] = ['bud'];
         dockerFiles.forEach(file => {
             args.push('-f');
             args.push(file);
         });
+        buildArgs.forEach((buildArg) => {
+            args.push('--build-arg');
+            args.push(buildArg);
+        })
         args.push('-t');
         args.push(image);
         args.push(context);

src/index.ts

@@ -29,8 +29,9 @@ export async function run(): Promise<void> {
 
 async function doBuildUsingDockerFiles(cli: BuildahCli, newImage: string, workspace: string, dockerFiles: string[]): Promise<void> {
     const context = path.join(workspace, core.getInput('context'));
+    const buildArgs = getInputList(core.getInput('build-args'));
     dockerFiles = dockerFiles.map(file => path.join(workspace, file));
-    const build = await cli.buildUsingDocker(newImage, context, dockerFiles);
+    const build = await cli.buildUsingDocker(newImage, context, dockerFiles, buildArgs);
     if (build.succeeded === false) {
         return Promise.reject(new Error('Failed building an image from docker files.'));
     }