updated usage

README.md

@@ -6,13 +6,46 @@ This action sets up a flutter environment for use in actions. It works on Linux,
 
 ```yaml
 steps:
-- uses: actions/checkout@master
+- uses: actions/checkout@v1
 - uses: actions/setup-java@v1
   with:
     java-version: '12.x'
-- uses: subosito/flutter-action@master
+- uses: subosito/flutter-action@v1
   with:
-    version: '1.7.8+hotfix.4'
+    flutter-version: '1.7.8+hotfix.4'
+- run: flutter pub get
+- run: flutter test
+- run: flutter build apk
+```
+
+Use latest release for particular channel:
+
+```yaml
+steps:
+- uses: actions/checkout@v1
+- uses: actions/setup-java@v1
+  with:
+    java-version: '12.x'
+- uses: subosito/flutter-action@v1
+  with:
+    channel: 'stable' # or: 'dev' or 'beta'
+- run: flutter pub get
+- run: flutter test
+- run: flutter build apk
+```
+
+Use latest release for particular version and/or channel:
+
+```yaml
+steps:
+- uses: actions/checkout@v1
+- uses: actions/setup-java@v1
+  with:
+    java-version: '12.x'
+- uses: subosito/flutter-action@v1
+  with:
+    flutter-version: '1.7.x' # you can use 1.7
+    channel: 'dev' # optional, default to: 'stable'
 - run: flutter pub get
 - run: flutter test
 - run: flutter build apk
@@ -29,13 +62,14 @@ jobs:
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
     steps:
-      - uses: actions/checkout@master
-      - uses: actions/setup-java@v1.0.1
+      - uses: actions/checkout@v1
+      - uses: actions/setup-java@v1
         with:
           java-version: '12.x'
-      - uses: subosito/flutter-action@master
+      - uses: subosito/flutter-action@v1
         with:
-          version: '1.7.8+hotfix.4'
+          flutter-version: '1.8.4'
+          channel: 'beta'
       - run: flutter pub get
       - run: flutter test
       - run: flutter build apk

__tests__/installer.test.ts

@@ -1,15 +1,28 @@
 import io = require('@actions/io');
 import fs = require('fs');
 import path = require('path');
+import nock = require('nock');
 
 const toolDir = path.join(__dirname, 'runner', 'tools');
 const tempDir = path.join(__dirname, 'runner', 'temp');
+const dataDir = path.join(__dirname, 'data');
 
 process.env['RUNNER_TOOL_CACHE'] = toolDir;
 process.env['RUNNER_TEMP'] = tempDir;
 
 import * as installer from '../src/installer';
 
+function osName(): string {
+  switch (process.platform) {
+    case 'win32':
+      return 'windows';
+    case 'darwin':
+      return 'macos';
+    default:
+      return process.platform;
+  }
+}
+
 describe('installer tests', () => {
   beforeAll(async () => {
     await io.rmRF(toolDir);
@@ -26,13 +39,8 @@ describe('installer tests', () => {
   }, 100000);
 
   it('Downloads flutter', async () => {
-    await installer.getFlutter('1.7.8+hotfix.4', 'stable');
-    const sdkDir = path.join(
-      toolDir,
-      'Flutter',
-      '1.7.8-hotfix.4-stable',
-      'x64'
-    );
+    await installer.getFlutter('1.0.0', 'stable');
+    const sdkDir = path.join(toolDir, 'flutter', '1.0.0-stable', 'x64');
 
     expect(fs.existsSync(`${sdkDir}.complete`)).toBe(true);
     expect(fs.existsSync(path.join(sdkDir, 'bin'))).toBe(true);
@@ -40,9 +48,62 @@ describe('installer tests', () => {
 
   it('Downloads flutter from beta channel', async () => {
     await installer.getFlutter('1.8.3', 'beta');
-    const sdkDir = path.join(toolDir, 'Flutter', '1.8.3-beta', 'x64');
+    const sdkDir = path.join(toolDir, 'flutter', '1.8.3-beta', 'x64');
 
     expect(fs.existsSync(`${sdkDir}.complete`)).toBe(true);
     expect(fs.existsSync(path.join(sdkDir, 'bin'))).toBe(true);
   }, 100000);
+
+  describe('get the latest release of a flutter version', () => {
+    beforeEach(() => {
+      const platform = osName();
+      nock('https://storage.googleapis.com', {allowUnmocked: true})
+        .get(`/flutter_infra/releases/releases_${platform}.json`)
+        .replyWithFile(200, path.join(dataDir, `releases_${platform}.json`));
+    });
+
+    afterEach(() => {
+      nock.cleanAll();
+      nock.enableNetConnect();
+    });
+
+    it('Downloads latest flutter release from stable channel', async () => {
+      await installer.getFlutter('', 'stable');
+      const sdkDir = path.join(
+        toolDir,
+        'flutter',
+        '1.7.8-hotfix.4-stable',
+        'x64'
+      );
+
+      expect(fs.existsSync(`${sdkDir}.complete`)).toBe(true);
+      expect(fs.existsSync(path.join(sdkDir, 'bin'))).toBe(true);
+    }, 100000);
+
+    it('Downloads latest flutter release of 1.7 when using version 1.7 from dev channel', async () => {
+      await installer.getFlutter('1.7', 'dev');
+      const sdkDir = path.join(toolDir, 'flutter', '1.7.11-dev', 'x64');
+
+      expect(fs.existsSync(`${sdkDir}.complete`)).toBe(true);
+      expect(fs.existsSync(path.join(sdkDir, 'bin'))).toBe(true);
+    }, 100000);
+
+    it('Downloads latest flutter release of 1.7 when using version 1.7.x from dev channel', async () => {
+      await installer.getFlutter('1.7.x', 'dev');
+      const sdkDir = path.join(toolDir, 'flutter', '1.7.11-dev', 'x64');
+
+      expect(fs.existsSync(`${sdkDir}.complete`)).toBe(true);
+      expect(fs.existsSync(path.join(sdkDir, 'bin'))).toBe(true);
+    }, 100000);
+  });
+
+  it('Throws if no location contains correct flutter version', async () => {
+    let thrown = false;
+    try {
+      await installer.getFlutter('1000.0', 'dev');
+    } catch {
+      thrown = true;
+    }
+    expect(thrown).toBe(true);
+  });
 });

action.yml

@@ -1,14 +1,17 @@
-name: 'Flutter Action'
+name: 'Flutter action'
 description: 'Setup your runner with Flutter environment'
 author: 'Alif Rachmawadi'
 inputs:
-  version:
+  flutter-version:
     description: 'The Flutter version to make available on the path'
-    required: true
+    required: false
   channel:
     description: 'The Flutter build release channel'
     required: false
     default: 'stable'
+  # Deprecated option, do not use. Will not be supported after October 1, 2019
+  version:
+    description: 'Deprecated. Use flutter-version instead. Will not be supported after October 1, 2019'
 runs:
   using: 'node12'
   main: 'lib/index.js'

lib/index.js

@@ -20,8 +20,8 @@ const installer = __importStar(require("./installer"));
 function run() {
     return __awaiter(this, void 0, void 0, function* () {
         try {
-            const version = core.getInput('version', { required: true });
-            const channel = core.getInput('channel', { required: false }) || 'stable';
+            const version = core.getInput('version') || core.getInput('flutter-version') || '';
+            const channel = core.getInput('channel') || 'stable';
             yield installer.getFlutter(version, channel);
         }
         catch (error) {

lib/installer.js

@@ -23,11 +23,14 @@ const io = __importStar(require("@actions/io"));
 const tc = __importStar(require("@actions/tool-cache"));
 const fs = __importStar(require("fs"));
 const path = __importStar(require("path"));
+const restm = __importStar(require("typed-rest-client/RestClient"));
+const semver = __importStar(require("semver"));
 const v4_1 = __importDefault(require("uuid/v4"));
 const exec_1 = require("@actions/exec/lib/exec");
 const IS_WINDOWS = process.platform === 'win32';
 const IS_DARWIN = process.platform === 'darwin';
 const IS_LINUX = process.platform === 'linux';
+const storageUrl = 'https://storage.googleapis.com/flutter_infra/releases';
 let tempDirectory = process.env['RUNNER_TEMP'] || '';
 if (!tempDirectory) {
     let baseLocation;
@@ -46,10 +49,13 @@ if (!tempDirectory) {
 }
 function getFlutter(version, channel) {
     return __awaiter(this, void 0, void 0, function* () {
-        // make semver compatible, eg: 1.7.8+hotfix.4 -> 1.7.8-hotfix.4
-        const semver = version.replace('+', '-');
-        const cleanver = `${semver}-${channel}`;
-        let toolPath = tc.find('Flutter', cleanver);
+        const versionPart = version.split('.');
+        if (versionPart[1] == null || versionPart[2] == null) {
+            version = version.concat('.x');
+        }
+        version = yield determineVersion(version, channel);
+        let cleanver = `${version.replace('+', '-')}-${channel}`;
+        let toolPath = tc.find('flutter', cleanver);
         if (toolPath) {
             core.debug(`Tool found in cache ${toolPath}`);
         }
@@ -60,7 +66,7 @@ function getFlutter(version, channel) {
             let tempDir = generateTempDir();
             const sdkDir = yield extractDownload(sdkFile, tempDir);
             core.debug(`Flutter sdk extracted to ${sdkDir}`);
-            toolPath = yield tc.cacheDir(sdkDir, 'Flutter', cleanver);
+            toolPath = yield tc.cacheDir(sdkDir, 'flutter', cleanver);
         }
         core.exportVariable('FLUTTER_HOME', toolPath);
         core.addPath(path.join(toolPath, 'bin'));
@@ -82,7 +88,7 @@ function extName() {
 function getDownloadInfo(version, channel) {
     const os = osName();
     const ext = extName();
-    const url = `https://storage.googleapis.com/flutter_infra/releases/${channel}/${os}/flutter_${os}_v${version}-${channel}.${ext}`;
+    const url = `${storageUrl}/${channel}/${os}/flutter_${os}_v${version}-${channel}.${ext}`;
     return {
         version,
         url
@@ -162,3 +168,37 @@ function extractZipDarwin(file, dest) {
         yield exec_1.exec(`"${unzipPath}"`, [file], { cwd: dest });
     });
 }
+function determineVersion(version, channel) {
+    return __awaiter(this, void 0, void 0, function* () {
+        if (version.endsWith('.x') || version === '') {
+            return yield getLatestVersion(version, channel);
+        }
+        return version;
+    });
+}
+function getLatestVersion(version, channel) {
+    return __awaiter(this, void 0, void 0, function* () {
+        const releasesUrl = `${storageUrl}/releases_${osName()}.json`;
+        const rest = new restm.RestClient('setup-go');
+        const storage = (yield rest.get(releasesUrl)).result;
+        if (!storage) {
+            throw new Error('unable to get latest version');
+        }
+        if (version.endsWith('.x')) {
+            const sver = version.slice(0, version.length - 2);
+            const releases = storage.releases.filter(release => release.version.startsWith(`v${sver}`) && release.channel === channel);
+            const versions = releases.map(release => release.version.slice(1, release.version.length));
+            const sortedVersions = versions.sort(semver.rcompare);
+            core.debug(`latest version of ${version} from channel ${channel} is ${sortedVersions[0]}`);
+            return sortedVersions[0];
+        }
+        const channelVersion = storage.releases.find(release => release.hash === storage.current_release[channel]);
+        if (!channelVersion) {
+            throw new Error(`unable to get latest version from channel ${channel}`);
+        }
+        let cver = channelVersion.version;
+        cver = cver.slice(1, cver.length);
+        core.debug(`latest version from channel ${channel} is ${cver}`);
+        return cver;
+    });
+}

node_modules/semver/package.json

@@ -1,39 +1,38 @@
 {
-  "_args": [
-    [
-      "semver@6.3.0",
-      "/Users/subosito/Code/playground/flutter-actions"
-    ]
-  ],
-  "_from": "semver@6.3.0",
+  "_from": "semver",
   "_id": "semver@6.3.0",
   "_inBundle": false,
   "_integrity": "sha512-b39TBaTSfV6yBrapU89p5fKekE2m/NwnDocOVruQFS1/veMgdzuPcnOM34M6CwxW8jH/lxEa5rBoDeUwu5HHTw==",
   "_location": "/semver",
   "_phantomChildren": {},
   "_requested": {
-    "type": "version",
+    "type": "tag",
     "registry": true,
-    "raw": "semver@6.3.0",
+    "raw": "semver",
     "name": "semver",
     "escapedName": "semver",
-    "rawSpec": "6.3.0",
+    "rawSpec": "",
     "saveSpec": null,
-    "fetchSpec": "6.3.0"
+    "fetchSpec": "latest"
   },
   "_requiredBy": [
+    "#USER",
+    "/",
     "/@actions/tool-cache",
     "/istanbul-lib-instrument"
   ],
   "_resolved": "https://registry.npmjs.org/semver/-/semver-6.3.0.tgz",
-  "_spec": "6.3.0",
-  "_where": "/Users/subosito/Code/playground/flutter-actions",
+  "_shasum": "ee0a64c8af5e8ceea67687b133761e1becbd1d3d",
+  "_spec": "semver",
+  "_where": "/Users/subosito/Code/subosito/flutter-action",
   "bin": {
     "semver": "./bin/semver.js"
   },
   "bugs": {
     "url": "https://github.com/npm/node-semver/issues"
   },
+  "bundleDependencies": false,
+  "deprecated": false,
   "description": "The semantic version parser used by npm.",
   "devDependencies": {
     "tap": "^14.3.1"

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "flutter-action",
-  "version": "1.0.1",
+  "version": "1.1.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -530,6 +530,15 @@
       "integrity": "sha512-yALhelO3i0hqZwhjtcr6dYyaLoCHbAMshwtj6cGxTvHZAKXHsYGdff6E8EPw3xLKY0ELUTQ69Q1rQiJENnccMA==",
       "dev": true
     },
+    "@types/nock": {
+      "version": "10.0.3",
+      "resolved": "https://registry.npmjs.org/@types/nock/-/nock-10.0.3.tgz",
+      "integrity": "sha512-OthuN+2FuzfZO3yONJ/QVjKmLEuRagS9TV9lEId+WHL9KhftYG+/2z+pxlr0UgVVXSpVD8woie/3fzQn8ft/Ow==",
+      "dev": true,
+      "requires": {
+        "@types/node": "*"
+      }
+    },
     "@types/node": {
       "version": "12.6.8",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-12.6.8.tgz",
@@ -702,6 +711,12 @@
       "integrity": "sha1-8S4PPF13sLHN2RRpQuTpbB5N1SU=",
       "dev": true
     },
+    "assertion-error": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/assertion-error/-/assertion-error-1.1.0.tgz",
+      "integrity": "sha512-jgsaNduz+ndvGyFt3uSuWqvy4lCnIJiovtouQN5JZHOKCS2QuhEdbcQHFhVksz2N2U9hXJo8odG7ETyWlEeuDw==",
+      "dev": true
+    },
     "assign-symbols": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/assign-symbols/-/assign-symbols-1.0.0.tgz",
@@ -1052,6 +1067,20 @@
       "integrity": "sha1-G2gcIf+EAzyCZUMJBolCDRhxUdw=",
       "dev": true
     },
+    "chai": {
+      "version": "4.2.0",
+      "resolved": "https://registry.npmjs.org/chai/-/chai-4.2.0.tgz",
+      "integrity": "sha512-XQU3bhBukrOsQCuwZndwGcCVQHyZi53fQ6Ys1Fym7E4olpIqqZZhhoFJoaKVvV17lWQoXYwgWN2nF5crA8J2jw==",
+      "dev": true,
+      "requires": {
+        "assertion-error": "^1.1.0",
+        "check-error": "^1.0.2",
+        "deep-eql": "^3.0.1",
+        "get-func-name": "^2.0.0",
+        "pathval": "^1.1.0",
+        "type-detect": "^4.0.5"
+      }
+    },
     "chalk": {
       "version": "2.4.2",
       "resolved": "https://registry.npmjs.org/chalk/-/chalk-2.4.2.tgz",
@@ -1063,6 +1092,12 @@
         "supports-color": "^5.3.0"
       }
     },
+    "check-error": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/check-error/-/check-error-1.0.2.tgz",
+      "integrity": "sha1-V00xLt2Iu13YkS6Sht1sCu1KrII=",
+      "dev": true
+    },
     "ci-info": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/ci-info/-/ci-info-2.0.0.tgz",
@@ -1308,6 +1343,21 @@
       "integrity": "sha1-6zkTMzRYd1y4TNGh+uBiEGu4dUU=",
       "dev": true
     },
+    "deep-eql": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/deep-eql/-/deep-eql-3.0.1.tgz",
+      "integrity": "sha512-+QeIQyN5ZuO+3Uk5DYh6/1eKO0m0YmJFGNmFHGACpf1ClL1nmlV/p4gNgbl2pJGxgXb4faqo6UE+M5ACEMyVcw==",
+      "dev": true,
+      "requires": {
+        "type-detect": "^4.0.0"
+      }
+    },
+    "deep-equal": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/deep-equal/-/deep-equal-1.0.1.tgz",
+      "integrity": "sha1-9dJgKStmDghO/0zbyfCK0yR0SLU=",
+      "dev": true
+    },
     "deep-is": {
       "version": "0.1.3",
       "resolved": "https://registry.npmjs.org/deep-is/-/deep-is-0.1.3.tgz",
@@ -2321,6 +2371,12 @@
       "integrity": "sha512-3t6rVToeoZfYSGd8YoLFR2DJkiQrIiUrGcjvFX2mDw3bn6k2OtwHN0TNCLbBO+w8qTvimhDkv+LSscbJY1vE6w==",
       "dev": true
     },
+    "get-func-name": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/get-func-name/-/get-func-name-2.0.0.tgz",
+      "integrity": "sha1-6td0q+5y4gQJQzoGY2YCPdaIekE=",
+      "dev": true
+    },
     "get-stdin": {
       "version": "7.0.0",
       "resolved": "https://registry.npmjs.org/get-stdin/-/get-stdin-7.0.0.tgz",
@@ -3817,6 +3873,46 @@
       "integrity": "sha512-1nh45deeb5olNY7eX82BkPO7SSxR5SSYJiPTrTdFUVYwAl8CKMA5N9PjTYkHiRjisVcxcQ1HXdLhx2qxxJzLNQ==",
       "dev": true
     },
+    "nock": {
+      "version": "10.0.6",
+      "resolved": "https://registry.npmjs.org/nock/-/nock-10.0.6.tgz",
+      "integrity": "sha512-b47OWj1qf/LqSQYnmokNWM8D88KvUl2y7jT0567NB3ZBAZFz2bWp2PC81Xn7u8F2/vJxzkzNZybnemeFa7AZ2w==",
+      "dev": true,
+      "requires": {
+        "chai": "^4.1.2",
+        "debug": "^4.1.0",
+        "deep-equal": "^1.0.0",
+        "json-stringify-safe": "^5.0.1",
+        "lodash": "^4.17.5",
+        "mkdirp": "^0.5.0",
+        "propagate": "^1.0.0",
+        "qs": "^6.5.1",
+        "semver": "^5.5.0"
+      },
+      "dependencies": {
+        "debug": {
+          "version": "4.1.1",
+          "resolved": "https://registry.npmjs.org/debug/-/debug-4.1.1.tgz",
+          "integrity": "sha512-pYAIzeRo8J6KPEaJ0VWOh5Pzkbw/RetuzehGM7QRRX5he4fPHx2rdKMB256ehJCkX+XRQm16eZLqLNS8RSZXZw==",
+          "dev": true,
+          "requires": {
+            "ms": "^2.1.1"
+          }
+        },
+        "ms": {
+          "version": "2.1.2",
+          "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
+          "integrity": "sha512-sGkPx+VjMtmA6MX27oA4FBFELFCZZ4S4XqeGOXCv68tT+jb3vk/RyaKWP0PTKyWtmLSM0b+adUTEvbs1PEaH2w==",
+          "dev": true
+        },
+        "semver": {
+          "version": "5.7.1",
+          "resolved": "https://registry.npmjs.org/semver/-/semver-5.7.1.tgz",
+          "integrity": "sha512-sauaDf/PZdVgrLTNYHRtpXa1iRiKcaebiKQ1BJdpQlWH2lCvexQdX55snPFyK7QzpudqbCI0qXFfOasHdyNDGQ==",
+          "dev": true
+        }
+      }
+    },
     "node-int64": {
       "version": "0.4.0",
       "resolved": "https://registry.npmjs.org/node-int64/-/node-int64-0.4.0.tgz",
@@ -4149,6 +4245,12 @@
         "pify": "^3.0.0"
       }
     },
+    "pathval": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/pathval/-/pathval-1.1.0.tgz",
+      "integrity": "sha1-uULm1L3mUwBe9rcTYd74cn0GReA=",
+      "dev": true
+    },
     "performance-now": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/performance-now/-/performance-now-2.1.0.tgz",
@@ -4240,6 +4342,12 @@
         "sisteransi": "^1.0.0"
       }
     },
+    "propagate": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/propagate/-/propagate-1.0.0.tgz",
+      "integrity": "sha1-AMLa7t2iDofjeCs0Stuhzd1q1wk=",
+      "dev": true
+    },
     "psl": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/psl/-/psl-1.2.0.tgz",
@@ -5177,6 +5285,12 @@
         "prelude-ls": "~1.1.2"
       }
     },
+    "type-detect": {
+      "version": "4.0.8",
+      "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-4.0.8.tgz",
+      "integrity": "sha512-0fr/mIH1dlO+x7TlcMy+bIDqKPsw/70tVyeHW787goQjhmqaZe10uwLujubK9q9Lg6Fiho1KUKDYz0Z7k7g5/g==",
+      "dev": true
+    },
     "type-fest": {
       "version": "0.6.0",
       "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.6.0.tgz",

package.json

@@ -1,8 +1,8 @@
 {
   "name": "flutter-action",
-  "version": "1.0.1",
+  "version": "1.1.0",
   "private": true,
-  "description": "flutter action",
+  "description": "Flutter environment for use in actions",
   "main": "lib/index.js",
   "scripts": {
     "build": "tsc",
@@ -27,16 +27,19 @@
     "@actions/exec": "^1.0.0",
     "@actions/io": "^1.0.0",
     "@actions/tool-cache": "^1.0.0",
+    "semver": "^6.3.0",
     "uuid": "^3.3.2"
   },
   "devDependencies": {
     "@types/jest": "^24.0.13",
+    "@types/nock": "^10.0.3",
     "@types/node": "^12.0.4",
-    "@types/semver": "^6.0.0",
+    "@types/semver": "^6.0.1",
     "@types/uuid": "^3.4.5",
     "husky": "^3.0.0",
     "jest": "^24.8.0",
     "jest-circus": "^24.7.1",
+    "nock": "^10.0.6",
     "prettier": "^1.17.1",
     "ts-jest": "^24.0.2",
     "typescript": "^3.5.1"

src/index.ts

@@ -3,8 +3,9 @@ import * as installer from './installer';
 
 async function run() {
   try {
-    const version = core.getInput('version', {required: true});
-    const channel = core.getInput('channel', {required: false}) || 'stable';
+    const version =
+      core.getInput('version') || core.getInput('flutter-version') || '';
+    const channel = core.getInput('channel') || 'stable';
 
     await installer.getFlutter(version, channel);
   } catch (error) {

src/installer.ts

@@ -3,6 +3,8 @@ import * as io from '@actions/io';
 import * as tc from '@actions/tool-cache';
 import * as fs from 'fs';
 import * as path from 'path';
+import * as restm from 'typed-rest-client/RestClient';
+import * as semver from 'semver';
 import uuidV4 from 'uuid/v4';
 import {exec} from '@actions/exec/lib/exec';
 
@@ -10,6 +12,8 @@ const IS_WINDOWS = process.platform === 'win32';
 const IS_DARWIN = process.platform === 'darwin';
 const IS_LINUX = process.platform === 'linux';
 
+const storageUrl = 'https://storage.googleapis.com/flutter_infra/releases';
+
 let tempDirectory = process.env['RUNNER_TEMP'] || '';
 
 if (!tempDirectory) {
@@ -32,10 +36,16 @@ export async function getFlutter(
   version: string,
   channel: string
 ): Promise<void> {
-  // make semver compatible, eg: 1.7.8+hotfix.4 -> 1.7.8-hotfix.4
-  const semver = version.replace('+', '-');
-  const cleanver = `${semver}-${channel}`;
-  let toolPath = tc.find('Flutter', cleanver);
+  const versionPart = version.split('.');
+
+  if (versionPart[1] == null || versionPart[2] == null) {
+    version = version.concat('.x');
+  }
+
+  version = await determineVersion(version, channel);
+
+  let cleanver = `${version.replace('+', '-')}-${channel}`;
+  let toolPath = tc.find('flutter', cleanver);
 
   if (toolPath) {
     core.debug(`Tool found in cache ${toolPath}`);
@@ -49,7 +59,7 @@ export async function getFlutter(
     const sdkDir = await extractDownload(sdkFile, tempDir);
     core.debug(`Flutter sdk extracted to ${sdkDir}`);
 
-    toolPath = await tc.cacheDir(sdkDir, 'Flutter', cleanver);
+    toolPath = await tc.cacheDir(sdkDir, 'flutter', cleanver);
   }
 
   core.exportVariable('FLUTTER_HOME', toolPath);
@@ -75,7 +85,7 @@ function getDownloadInfo(
 ): {version: string; url: string} {
   const os = osName();
   const ext = extName();
-  const url = `https://storage.googleapis.com/flutter_infra/releases/${channel}/${os}/flutter_${os}_v${version}-${channel}.${ext}`;
+  const url = `${storageUrl}/${channel}/${os}/flutter_${os}_v${version}-${channel}.${ext}`;
 
   return {
     version,
@@ -171,3 +181,79 @@ async function extractZipDarwin(file: string, dest: string): Promise<void> {
   );
   await exec(`"${unzipPath}"`, [file], {cwd: dest});
 }
+
+async function determineVersion(
+  version: string,
+  channel: string
+): Promise<string> {
+  if (version.endsWith('.x') || version === '') {
+    return await getLatestVersion(version, channel);
+  }
+
+  return version;
+}
+
+interface IFlutterChannel {
+  [key: string]: string;
+  beta: string;
+  dev: string;
+  stable: string;
+}
+
+interface IFlutterRelease {
+  hash: string;
+  channel: string;
+  version: string;
+}
+
+interface IFlutterStorage {
+  current_release: IFlutterChannel;
+  releases: IFlutterRelease[];
+}
+
+async function getLatestVersion(
+  version: string,
+  channel: string
+): Promise<string> {
+  const releasesUrl: string = `${storageUrl}/releases_${osName()}.json`;
+  const rest: restm.RestClient = new restm.RestClient('setup-go');
+  const storage: IFlutterStorage | null = (await rest.get<IFlutterStorage | null>(
+    releasesUrl
+  )).result;
+
+  if (!storage) {
+    throw new Error('unable to get latest version');
+  }
+
+  if (version.endsWith('.x')) {
+    const sver = version.slice(0, version.length - 2);
+    const releases = storage.releases.filter(
+      release =>
+        release.version.startsWith(`v${sver}`) && release.channel === channel
+    );
+    const versions = releases.map(release =>
+      release.version.slice(1, release.version.length)
+    );
+    const sortedVersions = versions.sort(semver.rcompare);
+
+    core.debug(
+      `latest version of ${version} from channel ${channel} is ${sortedVersions[0]}`
+    );
+
+    return sortedVersions[0];
+  }
+
+  const channelVersion = storage.releases.find(
+    release => release.hash === storage.current_release[channel]
+  );
+
+  if (!channelVersion) {
+    throw new Error(`unable to get latest version from channel ${channel}`);
+  }
+
+  let cver = channelVersion.version;
+  cver = cver.slice(1, cver.length);
+
+  core.debug(`latest version from channel ${channel} is ${cver}`);
+  return cver;
+}