Fallback to global.json if no version specified

.gitignore

@@ -4,4 +4,5 @@ node_modules/.bin
 node_modules/typescript
 node_modules/@types
 node_modules/prettier
-__tests__/runner/*
+__tests__/runner/*
+global.json

__tests__/installer.test.ts

@@ -9,6 +9,7 @@ const tempDir = path.join(__dirname, 'runner', 'temp');
 
 process.env['RUNNER_TOOL_CACHE'] = toolDir;
 process.env['RUNNER_TEMP'] = tempDir;
+import * as setup from '../src/setup-dotnet';
 import * as installer from '../src/installer';
 
 const IS_WINDOWS = process.platform === 'win32';
@@ -40,6 +41,25 @@ describe('installer tests', () => {
     }
   }, 100000);
 
+  it('Acquires version of dotnet if no matching version is installed', async () => {
+    const dotnetDir = path.join(toolDir, 'dncs', '2.2.105', os.arch());
+
+    const globalJsonPath = path.join(process.cwd(), 'global.json');
+    const jsonContents = `{${os.EOL}"sdk": {${os.EOL}"version": "2.2.105"${os.EOL}}${os.EOL}}`;
+    if (!fs.existsSync(globalJsonPath)) {
+      fs.writeFileSync(globalJsonPath, jsonContents);
+    }
+    await setup.run();
+
+    expect(fs.existsSync(`${dotnetDir}.complete`)).toBe(true);
+    if (IS_WINDOWS) {
+      expect(fs.existsSync(path.join(dotnetDir, 'dotnet.exe'))).toBe(true);
+    } else {
+      expect(fs.existsSync(path.join(dotnetDir, 'dotnet'))).toBe(true);
+    }
+    fs.unlinkSync(globalJsonPath);
+  }, 100000);
+
   it('Throws if no location contains correct dotnet version', async () => {
     let thrown = false;
     try {

lib/setup-dotnet.js

@@ -17,6 +17,7 @@ var __importStar = (this && this.__importStar) || function (mod) {
 Object.defineProperty(exports, "__esModule", { value: true });
 const core = __importStar(require("@actions/core"));
 const installer = __importStar(require("./installer"));
+const fs = __importStar(require("fs"));
 const path = __importStar(require("path"));
 function run() {
     return __awaiter(this, void 0, void 0, function* () {
@@ -25,7 +26,18 @@ function run() {
             // Version is optional.  If supplied, install / use from the tool cache
             // If not supplied then task is still used to setup proxy, auth, etc...
             //
-            const version = core.getInput('version');
+            let version = core.getInput('version');
+            if (!version) {
+                // Try to fall back to global.json
+                core.debug('No version found, trying to find version from global.json');
+                const globalJsonPath = path.join(process.cwd(), 'global.json');
+                if (fs.existsSync(globalJsonPath)) {
+                    const globalJson = JSON.parse(fs.readFileSync(globalJsonPath, { encoding: 'utf8' }));
+                    if (globalJson.sdk && globalJson.sdk.version) {
+                        version = globalJson.sdk.version;
+                    }
+                }
+            }
             if (version) {
                 const dotnetInstaller = new installer.DotnetCoreInstaller(version);
                 yield dotnetInstaller.installDotnet();
@@ -39,4 +51,5 @@ function run() {
         }
     });
 }
+exports.run = run;
 run();

src/setup-dotnet.ts

@@ -1,14 +1,29 @@
 import * as core from '@actions/core';
 import * as installer from './installer';
+import * as fs from 'fs';
 import * as path from 'path';
 
-async function run() {
+export async function run() {
   try {
     //
     // Version is optional.  If supplied, install / use from the tool cache
     // If not supplied then task is still used to setup proxy, auth, etc...
     //
-    const version = core.getInput('version');
+    let version: string = core.getInput('version');
+    if (!version) {
+      // Try to fall back to global.json
+      core.debug('No version found, trying to find version from global.json');
+      const globalJsonPath = path.join(process.cwd(), 'global.json');
+      if (fs.existsSync(globalJsonPath)) {
+        const globalJson = JSON.parse(
+          fs.readFileSync(globalJsonPath, {encoding: 'utf8'})
+        );
+        if (globalJson.sdk && globalJson.sdk.version) {
+          version = globalJson.sdk.version;
+        }
+      }
+    }
+
     if (version) {
       const dotnetInstaller = new installer.DotnetCoreInstaller(version);
       await dotnetInstaller.installDotnet();