Check if buildx installed (builder alias)

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

src/buildx.ts

@@ -1,5 +1,17 @@
+import fs from 'fs';
+import path from 'path';
+import os from 'os';
 import * as exec from './exec';
 
+interface DockerConfig {
+  credsStore?: string;
+  experimental?: string;
+  stackOrchestrator?: string;
+  aliases?: {
+    builder?: string;
+  };
+}
+
 export async function isAvailable(): Promise<Boolean> {
   return await exec.exec(`docker`, ['buildx'], true).then(res => {
     if (res.stderr != '' && !res.success) {
@@ -9,6 +21,18 @@ export async function isAvailable(): Promise<Boolean> {
   });
 }
 
+export async function isInstalled(): Promise<Boolean> {
+  const dockerHome: string = process.env.DOCKER_CONFIG || path.join(os.homedir(), '.docker');
+
+  const dockerCfgFile: string = path.join(dockerHome, 'config.json');
+  if (!fs.existsSync(dockerCfgFile)) {
+    return false;
+  }
+
+  const dockerCfg: DockerConfig = JSON.parse(fs.readFileSync(dockerCfgFile, {encoding: 'utf-8'}));
+  return dockerCfg.aliases?.builder == 'buildx';
+}
+
 export async function use(builder: string): Promise<void> {
   return await exec.exec(`docker`, ['buildx', 'use', '--builder', builder], false).then(res => {
     if (res.stderr != '' && !res.success) {

src/main.ts

@@ -13,12 +13,14 @@ async function run(): Promise<void> {
     }
 
     const inputs: Inputs = await loadInputs();
+    const buildxAvailable = await buildx.isAvailable();
+    const buildxInstalled = buildxAvailable && (await buildx.isInstalled());
+    const buildxEnabled = (await mustBuildx(inputs)) || buildxInstalled;
     let buildArgs: Array<string> = [];
-    const buildxEnabled = await mustBuildx(inputs);
 
     // Check buildx
     if (buildxEnabled) {
-      if (await !buildx.isAvailable()) {
+      if (!buildxAvailable) {
         core.setFailed(`Buildx is required but not available`);
         return;
       }