Add setup-buildx action (#71)

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

setup-buildx/src/github.ts

@@ -0,0 +1,12 @@
+import * as httpm from '@actions/http-client';
+
+export interface GitHubRelease {
+  id: number;
+  tag_name: string;
+}
+
+export const getRelease = async (version: string): Promise<GitHubRelease | null> => {
+  const url: string = `https://github.com/docker/buildx/releases/${version}`;
+  const http: httpm.HttpClient = new httpm.HttpClient('ghaction-docker-buildx');
+  return (await http.getJson<GitHubRelease>(url)).result;
+};

setup-buildx/src/installer.ts

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+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import * as semver from 'semver';
+import * as util from 'util';
+import * as github from './github';
+import * as core from '@actions/core';
+import * as tc from '@actions/tool-cache';
+
+const osPlat: string = os.platform();
+
+export async function buildx(inputVersion: string, dockerConfigHome: string): Promise<string> {
+  const release: github.GitHubRelease | null = await github.getRelease(inputVersion);
+  if (!release) {
+    throw new Error(`Cannot find buildx ${inputVersion} release`);
+  }
+  core.debug(`Release found: ${release.tag_name}`);
+  const version = release.tag_name.replace(/^v+|v+$/g, '');
+
+  let toolPath: string;
+  toolPath = tc.find('buildx', version);
+  if (!toolPath) {
+    const c = semver.clean(version) || '';
+    if (!semver.valid(c)) {
+      throw new Error(`Invalid Buildx version "${version}".`);
+    }
+    toolPath = await installBuildx(version);
+  }
+
+  const pluginsDir: string = path.join(dockerConfigHome, 'cli-plugins');
+  core.debug(`Plugins dir is ${pluginsDir}`);
+  if (!fs.existsSync(pluginsDir)) {
+    fs.mkdirSync(pluginsDir, {recursive: true});
+  }
+
+  const filename: string = osPlat == 'win32' ? 'docker-buildx.exe' : 'docker-buildx';
+  const pluginPath: string = path.join(pluginsDir, filename);
+  core.debug(`Plugin path is ${pluginPath}`);
+  fs.copyFileSync(path.join(toolPath, filename), pluginPath);
+
+  core.info('🔨 Fixing perms...');
+  fs.chmodSync(pluginPath, '0755');
+
+  return pluginPath;
+}
+
+async function installBuildx(version: string): Promise<string> {
+  version = semver.clean(version) || '';
+  const platform: string = osPlat == 'win32' ? 'windows' : osPlat;
+  const ext: string = osPlat == 'win32' ? '.exe' : '';
+  const filename: string = util.format('buildx-v%s.%s-amd64%s', version, platform, ext);
+  const targetFile: string = osPlat == 'win32' ? 'docker-buildx.exe' : 'docker-buildx';
+
+  const downloadUrl = util.format('https://github.com/docker/buildx/releases/download/v%s/%s', version, filename);
+  let downloadPath: string;
+
+  try {
+    core.info(`⬇️ Downloading ${downloadUrl}...`);
+    downloadPath = await tc.downloadTool(downloadUrl);
+    core.debug(`Downloaded to ${downloadPath}`);
+  } catch (error) {
+    throw error;
+  }
+
+  return await tc.cacheFile(downloadPath, targetFile, 'buildx', version);
+}

setup-buildx/src/main.ts

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+import * as child_process from 'child_process';
+import * as os from 'os';
+import * as path from 'path';
+import * as installer from './installer';
+import * as stateHelper from './state-helper';
+import * as core from '@actions/core';
+import * as exec from '@actions/exec';
+
+async function run(): Promise<void> {
+  try {
+    if (os.platform() !== 'linux') {
+      core.setFailed('Only supported on linux platform');
+      return;
+    }
+
+    const buildxVer: string = core.getInput('buildx-version') || 'latest';
+    const dockerConfigHome: string = process.env.DOCKER_CONFIG || path.join(os.homedir(), '.docker');
+    await installer.buildx(buildxVer, dockerConfigHome);
+
+    core.info('📣 Buildx info');
+    await exec.exec('docker', ['buildx', 'version']);
+
+    core.info('🔨 Creating a new builder instance...');
+    await exec.exec('docker', [
+      'buildx',
+      'create',
+      '--name',
+      `builder-${process.env.GITHUB_SHA}`,
+      '--driver',
+      'docker-container',
+      '--use'
+    ]);
+
+    core.info('🏃 Booting builder...');
+    await exec.exec('docker', ['buildx', 'inspect', '--bootstrap']);
+
+    core.info('🐳 Docker info');
+    await exec.exec('docker', ['info']);
+
+    core.info('🛒 Extracting available platforms...');
+    const inspect = child_process.execSync('docker buildx inspect', {
+      encoding: 'utf8'
+    });
+    for (const line of inspect.split(os.EOL)) {
+      if (line.startsWith('Platforms')) {
+        core.setOutput('platforms', line.replace('Platforms: ', '').replace(/\s/g, '').trim());
+        break;
+      }
+    }
+  } catch (error) {
+    core.setFailed(error.message);
+  }
+}
+
+async function cleanup(): Promise<void> {
+  try {
+    core.info('🚿 Removing builder instance...');
+    await exec.exec('docker', ['buildx', 'rm', `builder-${process.env.GITHUB_SHA}`]);
+  } catch (error) {
+    core.warning(error.message);
+  }
+}
+
+// Main
+if (!stateHelper.IsPost) {
+  run();
+}
+// Post
+else {
+  cleanup();
+}

setup-buildx/src/state-helper.ts

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+// From https://github.com/actions/checkout/blob/master/src/state-helper.ts
+
+import * as coreCommand from '@actions/core/lib/command';
+
+/**
+ * Indicates whether the POST action is running
+ */
+export const IsPost = !!process.env['STATE_isPost'];
+
+// Publish a variable so that when the POST action runs, it can determine it should run the cleanup logic.
+// This is necessary since we don't have a separate entry point.
+if (!IsPost) {
+  coreCommand.issueCommand('save-state', {name: 'isPost'}, 'true');
+}