Allow building buildx from source

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

.github/workflows/ci.yml

@@ -313,3 +313,37 @@ jobs:
           echo "Status:    ${{ steps.buildx.outputs.status }}"
           echo "Flags:     ${{ steps.buildx.outputs.flags }}"
           echo "Platforms: ${{ steps.buildx.outputs.platforms }}"
+
+  build-ref:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ref:
+          - master
+          - refs/tags/v0.5.1
+          - refs/pull/648/head
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v2
+      -
+        name: Set up Docker Buildx
+        uses: ./
+        with:
+          version: https://github.com/docker/buildx.git#${{ matrix.ref }}
+      -
+        name: Check version
+        run: |
+          docker buildx version
+      -
+        name: Create Dockerfile
+        run: |
+          cat > ./Dockerfile <<EOL
+          FROM alpine
+          EOL
+      -
+        name: Build
+        uses: docker/build-push-action@master
+        with:
+          context: .

.prettierrc.json

@@ -1,5 +1,5 @@
 {
-  "printWidth": 120,
+  "printWidth": 240,
   "tabWidth": 2,
   "useTabs": false,
   "semi": true,

README.md

@@ -125,7 +125,7 @@ Following inputs can be used as `step.with` keys
 
 | Name               | Type    | Description                       |
 |--------------------|---------|-----------------------------------|
-| `version`          | String  | [Buildx](https://github.com/docker/buildx) version. (eg. `v0.3.0`, `latest`) |
+| `version`          | String  | [buildx](https://github.com/docker/buildx) version. (eg. `v0.3.0`, `latest`, `https://github.com/docker/buildx.git#master`) |
 | `driver`           | String  | Sets the [builder driver](https://github.com/docker/buildx/blob/master/docs/reference/buildx_create.md#driver) to be used (default `docker-container`) |
 | `driver-opts`      | CSV     | List of additional [driver-specific options](https://github.com/docker/buildx/blob/master/docs/reference/buildx_create.md#driver-opt) (eg. `image=moby/buildkit:master`) |
 | `buildkitd-flags`  | String  | [Flags for buildkitd](https://github.com/moby/buildkit/blob/master/docs/buildkitd.toml.md) daemon (since [buildx v0.3.0](https://github.com/docker/buildx/releases/tag/v0.3.0)) |

__tests__/buildx.test.ts

@@ -1,10 +1,19 @@
-import fs = require('fs');
+import * as fs from 'fs';
-import * as buildx from '../src/buildx';
-import * as path from 'path';
 import * as os from 'os';
+import * as path from 'path';
+import * as buildx from '../src/buildx';
+import * as context from '../src/context';
 import * as semver from 'semver';
 import * as exec from '@actions/exec';
 
+jest.spyOn(context, 'tmpDir').mockImplementation((): string => {
+  const tmpDir = path.join('/tmp/.docker-setup-buildx-jest').split(path.sep).join(path.posix.sep);
+  if (!fs.existsSync(tmpDir)) {
+    fs.mkdirSync(tmpDir, {recursive: true});
+  }
+  return tmpDir;
+});
+
 describe('isAvailable', () => {
   const execSpy: jest.SpyInstance = jest.spyOn(exec, 'getExecOutput');
   buildx.isAvailable();
@@ -41,9 +50,20 @@ describe('parseVersion', () => {
   test.each([
     ['github.com/docker/buildx 0.4.1+azure bda4882a65349ca359216b135896bddc1d92461c', '0.4.1'],
     ['github.com/docker/buildx v0.4.1 bda4882a65349ca359216b135896bddc1d92461c', '0.4.1'],
-    ['github.com/docker/buildx v0.4.2 fb7b670b764764dc4716df3eba07ffdae4cc47b2', '0.4.2']
+    ['github.com/docker/buildx v0.4.2 fb7b670b764764dc4716df3eba07ffdae4cc47b2', '0.4.2'],
+    ['github.com/docker/buildx f117971 f11797113e5a9b86bd976329c5dbb8a8bfdfadfa', 'f117971']
   ])('given %p', async (stdout, expected) => {
-    expect(await buildx.parseVersion(stdout)).toEqual(expected);
+    expect(buildx.parseVersion(stdout)).toEqual(expected);
+  });
+});
+
+describe('satisfies', () => {
+  test.each([
+    ['0.4.1', '>=0.3.2', true],
+    ['bda4882a65349ca359216b135896bddc1d92461c', '>0.1.0', false],
+    ['f117971', '>0.6.0', true]
+  ])('given %p', async (version, range, expected) => {
+    expect(buildx.satisfies(version, range)).toBe(expected);
   });
 });
 
@@ -72,6 +92,15 @@ describe('inspect', () => {
   );
 });
 
+describe('build', () => {
+  it.skip('valid', async () => {
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'setup-buildx-'));
+    const buildxBin = await buildx.build('https://github.com/docker/buildx.git#refs/pull/648/head', tmpDir);
+    console.log(buildxBin);
+    expect(fs.existsSync(buildxBin)).toBe(true);
+  }, 100000);
+});
+
 describe('install', () => {
   const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'setup-buildx-'));
   it('acquires v0.4.1 version of buildx', async () => {

__tests__/context.test.ts

@@ -1,6 +1,16 @@
+import * as fs from 'fs';
 import * as os from 'os';
+import * as path from 'path';
 import * as context from '../src/context';
 
+jest.spyOn(context, 'tmpDir').mockImplementation((): string => {
+  const tmpDir = path.join('/tmp/.docker-setup-buildx-jest').split(path.sep).join(path.posix.sep);
+  if (!fs.existsSync(tmpDir)) {
+    fs.mkdirSync(tmpDir, {recursive: true});
+  }
+  return tmpDir;
+});
+
 describe('getInputList', () => {
   it('handles single line correctly', async () => {
     await setInput('foo', 'bar');

__tests__/git.test.ts

@@ -0,0 +1,9 @@
+import * as git from '../src/git';
+
+describe('git', () => {
+  it('returns git remote ref', async () => {
+    const ref: string = await git.getRemoteSha('https://github.com/docker/buildx.git', 'refs/pull/648/head');
+    console.log(`ref: ${ref}`);
+    expect(ref).toEqual('f11797113e5a9b86bd976329c5dbb8a8bfdfadfa');
+  });
+});

__tests__/util.test.ts

@@ -0,0 +1,11 @@
+import * as util from '../src/util';
+
+describe('isValidUrl', () => {
+  test.each([
+    ['https://github.com/docker/buildx.git', true],
+    ['https://github.com/docker/buildx.git#refs/pull/648/head', true],
+    ['v0.4.1', false]
+  ])('given %p', async (url, expected) => {
+    expect(util.isValidUrl(url)).toEqual(expected);
+  });
+});

codecov.yml

@@ -0,0 +1,3 @@
+comment: false
+github_checks:
+  annotations: false

dist/index.js

@@ -35,12 +35,13 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 Object.defineProperty(exports, "__esModule", ({ value: true }));
-exports.getBuildKitVersion = exports.install = exports.inspect = exports.parseVersion = exports.getVersion = exports.isAvailable = void 0;
+exports.getBuildKitVersion = exports.install = exports.build = exports.inspect = exports.satisfies = exports.parseVersion = exports.getVersion = exports.isAvailable = void 0;
 const fs = __importStar(__nccwpck_require__(5747));
 const path = __importStar(__nccwpck_require__(5622));
 const semver = __importStar(__nccwpck_require__(1383));
 const util = __importStar(__nccwpck_require__(1669));
 const context = __importStar(__nccwpck_require__(3842));
+const git = __importStar(__nccwpck_require__(3374));
 const github = __importStar(__nccwpck_require__(5928));
 const core = __importStar(__nccwpck_require__(2186));
 const exec = __importStar(__nccwpck_require__(1514));
@@ -78,15 +79,17 @@ function getVersion() {
 }
 exports.getVersion = getVersion;
 function parseVersion(stdout) {
-    return __awaiter(this, void 0, void 0, function* () {
+    const matches = /\sv?([0-9a-f]{7}|[0-9.]+)/.exec(stdout);
-        const matches = /\sv?([0-9.]+)/.exec(stdout);
+    if (!matches) {
-        if (!matches) {
+        throw new Error(`Cannot parse buildx version`);
-            throw new Error(`Cannot parse buildx version`);
+    }
-        }
+    return matches[1];
-        return semver.clean(matches[1]);
-    });
 }
 exports.parseVersion = parseVersion;
+function satisfies(version, range) {
+    return semver.satisfies(version, range) || /^[0-9a-f]{7}$/.exec(version) !== null;
+}
+exports.satisfies = satisfies;
 function inspect(name) {
     return __awaiter(this, void 0, void 0, function* () {
         return yield exec
@@ -142,6 +145,33 @@ function inspect(name) {
     });
 }
 exports.inspect = inspect;
+function build(inputBuildRef, dockerConfigHome) {
+    return __awaiter(this, void 0, void 0, function* () {
+        let [repo, ref] = inputBuildRef.split('#');
+        if (ref.length == 0) {
+            ref = 'master';
+        }
+        const sha = yield git.getRemoteSha(repo, ref);
+        core.debug(`Remote ref ${sha} found`);
+        let toolPath;
+        toolPath = tc.find('buildx', sha);
+        if (!toolPath) {
+            const outFolder = path.join(context.tmpDir(), 'out').split(path.sep).join(path.posix.sep);
+            toolPath = yield exec
+                .getExecOutput('docker', ['buildx', 'build', '--target', 'binaries', '--build-arg', 'BUILDKIT_CONTEXT_KEEP_GIT_DIR=1', '--output', `type=local,dest=${outFolder}`, inputBuildRef], {
+                ignoreReturnCode: true
+            })
+                .then(res => {
+                if (res.stderr.length > 0 && res.exitCode != 0) {
+                    core.warning(res.stderr.trim());
+                }
+                return tc.cacheFile(`${outFolder}/buildx`, context.osPlat == 'win32' ? 'docker-buildx.exe' : 'docker-buildx', 'buildx', sha);
+            });
+        }
+        return setPlugin(toolPath, dockerConfigHome);
+    });
+}
+exports.build = build;
 function install(inputVersion, dockerConfigHome) {
     return __awaiter(this, void 0, void 0, function* () {
         const release = yield github.getRelease(inputVersion);
@@ -159,6 +189,12 @@ function install(inputVersion, dockerConfigHome) {
             }
             toolPath = yield download(version);
         }
+        return setPlugin(toolPath, dockerConfigHome);
+    });
+}
+exports.install = install;
+function setPlugin(toolPath, dockerConfigHome) {
+    return __awaiter(this, void 0, void 0, function* () {
         const pluginsDir = path.join(dockerConfigHome, 'cli-plugins');
         core.debug(`Plugins dir is ${pluginsDir}`);
         if (!fs.existsSync(pluginsDir)) {
@@ -173,7 +209,6 @@ function install(inputVersion, dockerConfigHome) {
         return pluginPath;
     });
 }
-exports.install = install;
 function download(version) {
     return __awaiter(this, void 0, void 0, function* () {
         const targetFile = context.osPlat == 'win32' ? 'docker-buildx.exe' : 'docker-buildx';
@@ -286,21 +321,33 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
         step((generator = generator.apply(thisArg, _arguments || [])).next());
     });
 };
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
 Object.defineProperty(exports, "__esModule", ({ value: true }));
-exports.setOutput = exports.asyncForEach = exports.getInputList = exports.getInputs = exports.osArch = exports.osPlat = void 0;
+exports.setOutput = exports.asyncForEach = exports.getInputList = exports.getInputs = exports.tmpDir = exports.osArch = exports.osPlat = void 0;
+const fs_1 = __importDefault(__nccwpck_require__(5747));
 const os = __importStar(__nccwpck_require__(2087));
+const path_1 = __importDefault(__nccwpck_require__(5622));
 const core = __importStar(__nccwpck_require__(2186));
 const command_1 = __nccwpck_require__(7351);
+let _tmpDir;
 exports.osPlat = os.platform();
 exports.osArch = os.arch();
+function tmpDir() {
+    if (!_tmpDir) {
+        _tmpDir = fs_1.default.mkdtempSync(path_1.default.join(os.tmpdir(), 'docker-setup-buildx-')).split(path_1.default.sep).join(path_1.default.posix.sep);
+    }
+    return _tmpDir;
+}
+exports.tmpDir = tmpDir;
 function getInputs() {
     return __awaiter(this, void 0, void 0, function* () {
         return {
             version: core.getInput('version'),
             driver: core.getInput('driver') || 'docker-container',
             driverOpts: yield getInputList('driver-opts', true),
-            buildkitdFlags: core.getInput('buildkitd-flags') ||
+            buildkitdFlags: core.getInput('buildkitd-flags') || '--allow-insecure-entitlement security.insecure --allow-insecure-entitlement network.host',
-                '--allow-insecure-entitlement security.insecure --allow-insecure-entitlement network.host',
             install: core.getBooleanInput('install'),
             use: core.getBooleanInput('use'),
             endpoint: core.getInput('endpoint'),
@@ -337,6 +384,66 @@ exports.setOutput = setOutput;
 
 /***/ }),
 
+/***/ 3374:
+/***/ (function(__unused_webpack_module, exports, __nccwpck_require__) {
+
+"use strict";
+
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+Object.defineProperty(exports, "__esModule", ({ value: true }));
+exports.getRemoteSha = void 0;
+const exec = __importStar(__nccwpck_require__(1514));
+function getRemoteSha(repo, ref) {
+    return __awaiter(this, void 0, void 0, function* () {
+        return yield exec
+            .getExecOutput(`git`, ['ls-remote', repo, ref], {
+            ignoreReturnCode: true,
+            silent: true
+        })
+            .then(res => {
+            if (res.stderr.length > 0 && res.exitCode != 0) {
+                throw new Error(res.stderr);
+            }
+            const [rsha, rref] = res.stdout.trim().split(/[\s\t]/);
+            if (rsha.length == 0) {
+                throw new Error(`Cannot find remote ref for ${repo}#${ref}`);
+            }
+            return rsha;
+        });
+    });
+}
+exports.getRemoteSha = getRemoteSha;
+//# sourceMappingURL=git.js.map
+
+/***/ }),
+
 /***/ 5928:
 /***/ (function(__unused_webpack_module, exports, __nccwpck_require__) {
 
@@ -419,10 +526,10 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
 Object.defineProperty(exports, "__esModule", ({ value: true }));
 const os = __importStar(__nccwpck_require__(2087));
 const path = __importStar(__nccwpck_require__(5622));
-const semver = __importStar(__nccwpck_require__(1383));
 const buildx = __importStar(__nccwpck_require__(9295));
 const context = __importStar(__nccwpck_require__(3842));
 const stateHelper = __importStar(__nccwpck_require__(8647));
+const util = __importStar(__nccwpck_require__(4024));
 const core = __importStar(__nccwpck_require__(2186));
 const exec = __importStar(__nccwpck_require__(1514));
 function run() {
@@ -435,8 +542,13 @@ function run() {
             core.endGroup();
             const inputs = yield context.getInputs();
             const dockerConfigHome = process.env.DOCKER_CONFIG || path.join(os.homedir(), '.docker');
-            if (!(yield buildx.isAvailable()) || inputs.version) {
+            if (util.isValidUrl(inputs.version)) {
-                core.startGroup(`Installing buildx`);
+                core.startGroup(`Build and install buildx`);
+                yield buildx.build(inputs.version, dockerConfigHome);
+                core.endGroup();
+            }
+            else if (!(yield buildx.isAvailable()) || inputs.version) {
+                core.startGroup(`Download and install buildx`);
                 yield buildx.install(inputs.version || 'latest', dockerConfigHome);
                 core.endGroup();
             }
@@ -447,7 +559,7 @@ function run() {
             if (inputs.driver !== 'docker') {
                 core.startGroup(`Creating a new builder instance`);
                 let createArgs = ['buildx', 'create', '--name', builderName, '--driver', inputs.driver];
-                if (semver.satisfies(buildxVersion, '>=0.3.0')) {
+                if (buildx.satisfies(buildxVersion, '>=0.3.0')) {
                     yield context.asyncForEach(inputs.driverOpts, (driverOpt) => __awaiter(this, void 0, void 0, function* () {
                         createArgs.push('--driver-opt', driverOpt);
                     }));
@@ -468,7 +580,7 @@ function run() {
                 core.endGroup();
                 core.startGroup(`Booting builder`);
                 let bootstrapArgs = ['buildx', 'inspect', '--bootstrap'];
-                if (semver.satisfies(buildxVersion, '>=0.4.0')) {
+                if (buildx.satisfies(buildxVersion, '>=0.4.0')) {
                     bootstrapArgs.push('--builder', builderName);
                 }
                 yield exec.exec('docker', bootstrapArgs);
@@ -593,6 +705,27 @@ if (!exports.IsPost) {
 
 /***/ }),
 
+/***/ 4024:
+/***/ ((__unused_webpack_module, exports) => {
+
+"use strict";
+
+Object.defineProperty(exports, "__esModule", ({ value: true }));
+exports.isValidUrl = void 0;
+function isValidUrl(url) {
+    try {
+        new URL(url);
+    }
+    catch (e) {
+        return false;
+    }
+    return true;
+}
+exports.isValidUrl = isValidUrl;
+//# sourceMappingURL=util.js.map
+
+/***/ }),
+
 /***/ 7351:
 /***/ (function(__unused_webpack_module, exports, __nccwpck_require__) {
 

src/buildx.ts

@@ -3,6 +3,7 @@ import * as path from 'path';
 import * as semver from 'semver';
 import * as util from 'util';
 import * as context from './context';
+import * as git from './git';
 import * as github from './github';
 import * as core from '@actions/core';
 import * as exec from '@actions/exec';
@@ -46,12 +47,16 @@ export async function getVersion(): Promise<string> {
     });
 }
 
-export async function parseVersion(stdout: string): Promise<string> {
+export function parseVersion(stdout: string): string {
-  const matches = /\sv?([0-9.]+)/.exec(stdout);
+  const matches = /\sv?([0-9a-f]{7}|[0-9.]+)/.exec(stdout);
   if (!matches) {
     throw new Error(`Cannot parse buildx version`);
   }
-  return semver.clean(matches[1]);
+  return matches[1];
+}
+
+export function satisfies(version: string, range: string): boolean {
+  return semver.satisfies(version, range) || /^[0-9a-f]{7}$/.exec(version) !== null;
 }
 
 export async function inspect(name: string): Promise<Builder> {
@@ -106,6 +111,34 @@ export async function inspect(name: string): Promise<Builder> {
     });
 }
 
+export async function build(inputBuildRef: string, dockerConfigHome: string): Promise<string> {
+  let [repo, ref] = inputBuildRef.split('#');
+  if (ref.length == 0) {
+    ref = 'master';
+  }
+
+  const sha = await git.getRemoteSha(repo, ref);
+  core.debug(`Remote ref ${sha} found`);
+
+  let toolPath: string;
+  toolPath = tc.find('buildx', sha);
+  if (!toolPath) {
+    const outFolder = path.join(context.tmpDir(), 'out').split(path.sep).join(path.posix.sep);
+    toolPath = await exec
+      .getExecOutput('docker', ['buildx', 'build', '--target', 'binaries', '--build-arg', 'BUILDKIT_CONTEXT_KEEP_GIT_DIR=1', '--output', `type=local,dest=${outFolder}`, inputBuildRef], {
+        ignoreReturnCode: true
+      })
+      .then(res => {
+        if (res.stderr.length > 0 && res.exitCode != 0) {
+          core.warning(res.stderr.trim());
+        }
+        return tc.cacheFile(`${outFolder}/buildx`, context.osPlat == 'win32' ? 'docker-buildx.exe' : 'docker-buildx', 'buildx', sha);
+      });
+  }
+
+  return setPlugin(toolPath, dockerConfigHome);
+}
+
 export async function install(inputVersion: string, dockerConfigHome: string): Promise<string> {
   const release: github.GitHubRelease | null = await github.getRelease(inputVersion);
   if (!release) {
@@ -124,6 +157,10 @@ export async function install(inputVersion: string, dockerConfigHome: string): P
     toolPath = await download(version);
   }
 
+  return setPlugin(toolPath, dockerConfigHome);
+}
+
+async function setPlugin(toolPath: string, dockerConfigHome: string): Promise<string> {
   const pluginsDir: string = path.join(dockerConfigHome, 'cli-plugins');
   core.debug(`Plugins dir is ${pluginsDir}`);
   if (!fs.existsSync(pluginsDir)) {
@@ -143,11 +180,7 @@ export async function install(inputVersion: string, dockerConfigHome: string): P
 
 async function download(version: string): Promise<string> {
   const targetFile: string = context.osPlat == 'win32' ? 'docker-buildx.exe' : 'docker-buildx';
-  const downloadUrl = util.format(
+  const downloadUrl = util.format('https://github.com/docker/buildx/releases/download/v%s/%s', version, await filename(version));
-    'https://github.com/docker/buildx/releases/download/v%s/%s',
-    version,
-    await filename(version)
-  );
   let downloadPath: string;
 
   try {

src/context.ts

@@ -1,10 +1,20 @@
+import fs from 'fs';
 import * as os from 'os';
+import path from 'path';
 import * as core from '@actions/core';
 import {issueCommand} from '@actions/core/lib/command';
 
+let _tmpDir: string;
 export const osPlat: string = os.platform();
 export const osArch: string = os.arch();
 
+export function tmpDir(): string {
+  if (!_tmpDir) {
+    _tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'docker-setup-buildx-')).split(path.sep).join(path.posix.sep);
+  }
+  return _tmpDir;
+}
+
 export interface Inputs {
   version: string;
   driver: string;
@@ -21,9 +31,7 @@ export async function getInputs(): Promise<Inputs> {
     version: core.getInput('version'),
     driver: core.getInput('driver') || 'docker-container',
     driverOpts: await getInputList('driver-opts', true),
-    buildkitdFlags:
+    buildkitdFlags: core.getInput('buildkitd-flags') || '--allow-insecure-entitlement security.insecure --allow-insecure-entitlement network.host',
-      core.getInput('buildkitd-flags') ||
-      '--allow-insecure-entitlement security.insecure --allow-insecure-entitlement network.host',
     install: core.getBooleanInput('install'),
     use: core.getBooleanInput('use'),
     endpoint: core.getInput('endpoint'),
@@ -39,10 +47,7 @@ export async function getInputList(name: string, ignoreComma?: boolean): Promise
   return items
     .split(/\r?\n/)
     .filter(x => x)
-    .reduce<string[]>(
+    .reduce<string[]>((acc, line) => acc.concat(!ignoreComma ? line.split(',').filter(x => x) : line).map(pat => pat.trim()), []);
-      (acc, line) => acc.concat(!ignoreComma ? line.split(',').filter(x => x) : line).map(pat => pat.trim()),
-      []
-    );
 }
 
 export const asyncForEach = async (array, callback) => {

src/git.ts

@@ -0,0 +1,19 @@
+import * as exec from '@actions/exec';
+
+export async function getRemoteSha(repo: string, ref: string): Promise<string> {
+  return await exec
+    .getExecOutput(`git`, ['ls-remote', repo, ref], {
+      ignoreReturnCode: true,
+      silent: true
+    })
+    .then(res => {
+      if (res.stderr.length > 0 && res.exitCode != 0) {
+        throw new Error(res.stderr);
+      }
+      const [rsha, rref] = res.stdout.trim().split(/[\s\t]/);
+      if (rsha.length == 0) {
+        throw new Error(`Cannot find remote ref for ${repo}#${ref}`);
+      }
+      return rsha;
+    });
+}

src/main.ts

@@ -1,9 +1,9 @@
 import * as os from 'os';
 import * as path from 'path';
-import * as semver from 'semver';
 import * as buildx from './buildx';
 import * as context from './context';
 import * as stateHelper from './state-helper';
+import * as util from './util';
 import * as core from '@actions/core';
 import * as exec from '@actions/exec';
 
@@ -17,8 +17,12 @@ async function run(): Promise<void> {
     const inputs: context.Inputs = await context.getInputs();
     const dockerConfigHome: string = process.env.DOCKER_CONFIG || path.join(os.homedir(), '.docker');
 
-    if (!(await buildx.isAvailable()) || inputs.version) {
+    if (util.isValidUrl(inputs.version)) {
-      core.startGroup(`Installing buildx`);
+      core.startGroup(`Build and install buildx`);
+      await buildx.build(inputs.version, dockerConfigHome);
+      core.endGroup();
+    } else if (!(await buildx.isAvailable()) || inputs.version) {
+      core.startGroup(`Download and install buildx`);
       await buildx.install(inputs.version || 'latest', dockerConfigHome);
       core.endGroup();
     }
@@ -31,7 +35,7 @@ async function run(): Promise<void> {
     if (inputs.driver !== 'docker') {
       core.startGroup(`Creating a new builder instance`);
       let createArgs: Array<string> = ['buildx', 'create', '--name', builderName, '--driver', inputs.driver];
-      if (semver.satisfies(buildxVersion, '>=0.3.0')) {
+      if (buildx.satisfies(buildxVersion, '>=0.3.0')) {
         await context.asyncForEach(inputs.driverOpts, async driverOpt => {
           createArgs.push('--driver-opt', driverOpt);
         });
@@ -53,7 +57,7 @@ async function run(): Promise<void> {
 
       core.startGroup(`Booting builder`);
       let bootstrapArgs: Array<string> = ['buildx', 'inspect', '--bootstrap'];
-      if (semver.satisfies(buildxVersion, '>=0.4.0')) {
+      if (buildx.satisfies(buildxVersion, '>=0.4.0')) {
         bootstrapArgs.push('--builder', builderName);
       }
       await exec.exec('docker', bootstrapArgs);

src/util.ts

@@ -0,0 +1,8 @@
+export function isValidUrl(url: string): boolean {
+  try {
+    new URL(url);
+  } catch (e) {
+    return false;
+  }
+  return true;
+}