Add OpenTofu version file support (#59)

Signed-off-by: Brendon Smith <bws@bws.bio>

.github/workflows/data/local/.opentofu-version

@@ -0,0 +1 @@
+latest

.github/workflows/setup-tofu.yml

@@ -14,6 +14,25 @@ env:
   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
 jobs:
+  tofu-version-files:
+    name: 'OpenTofu Version Files'
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        tofu-version-files: ['./.github/workflows/data/local/.opentofu-version']
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+
+    - name: Setup OpenTofu - ${{ matrix['tofu-version-files'] }}
+      uses: ./
+      with:
+        tofu_version_file: ${{ matrix['tofu-version-files'] }}
+        tofu_wrapper: false
+
+    - name: Validate that OpenTofu was installed
+      run: tofu version | grep 'OpenTofu v'
   tofu-versions:
     name: 'OpenTofu Versions'
     runs-on: ${{ matrix.os }}

README.md

@@ -28,6 +28,17 @@ steps:
     tofu_version: 1.6.0
 ```
 
+You can also specify the version in a file (e.g., `.opentofu-version`):
+
+```yaml
+steps:
+  - uses: opentofu/setup-opentofu@v1
+    with:
+      tofu_version_file: .opentofu-version
+```
+
+Supported version syntax is the same as for the `tofu_version` input. If both `tofu_version` and `tofu_version_file` are provided, the version number in the file takes precedence.
+
 Credentials for Terraform Cloud ([app.terraform.io](https://app.terraform.io/)) can be configured:
 
 ```yaml
@@ -248,6 +259,8 @@ The action supports the following inputs:
   for available range specifications). Examples are: `<1.6.0-beta`, `~1.6.0-alpha`, `1.6.0-alpha2` (all three installing
   the latest available `1.6.0-alpha2` version). Prerelease versions can be specified and a range will stay within the
   given tag such as `beta` or `rc`. If no version is given, it will default to `latest`.
+- `tofu_version_file` - (optional) Path to a file containing the OpenTofu version to install. Supported version syntax
+  is the same as for the `tofu_version` input. Takes precedence over `tofu_version` if both are provided.
 - `tofu_wrapper` - (optional) Whether to install a wrapper to wrap subsequent calls of
   the `tofu` binary and expose its STDOUT, STDERR, and exit code as outputs
   named `stdout`, `stderr`, and `exitcode` respectively. Defaults to `true`.

action.yml

@@ -13,6 +13,9 @@ inputs:
     description: 'The version of OpenTofu CLI to install. If no version is given, it will default to `latest`.'
     default: 'latest'
     required: false
+  tofu_version_file:
+    description: 'Path to a file containing the OpenTofu version to install. Takes precedence over `tofu_version` if both are provided.'
+    required: false
   tofu_wrapper:
     description: 'Whether or not to install a wrapper to wrap subsequent calls of the `tofu` binary and expose its STDOUT, STDERR, and exit code as outputs named `stdout`, `stderr`, and `exitcode` respectively. Defaults to `true`.'
     default: 'true'

dist/index.js

@@ -247,7 +247,8 @@ credentials "${credentialsHostname}" {
 async function run () {
   try {
     // Gather GitHub Actions inputs
-    const version = core.getInput('tofu_version');
+    let version = core.getInput('tofu_version');
+    const versionFile = core.getInput('tofu_version_file');
     const credentialsHostname = core.getInput('cli_config_credentials_hostname');
     const credentialsToken = core.getInput('cli_config_credentials_token');
     const wrapper = core.getInput('tofu_wrapper') === 'true';
@@ -258,6 +259,27 @@ async function run () {
       githubToken = process.env.GITHUB_TOKEN;
     }
 
+    // If tofu_version_file is provided, read the version from the file
+    if (versionFile) {
+      try {
+        core.debug(`Reading OpenTofu version from file: ${versionFile}`);
+        const fileVersion = await fs.readFile(versionFile, 'utf8');
+        const trimmedVersion = fileVersion.trim();
+        if (trimmedVersion) {
+          version = trimmedVersion;
+          core.debug(`Using version from file: ${version}`);
+        } else {
+          core.warning(
+            `Version file ${versionFile} is empty, using tofu_version input: ${version}`
+          );
+        }
+      } catch (error) {
+        core.warning(
+          `Failed to read version from file ${versionFile}: ${error.message}. Using tofu_version input: ${version}`
+        );
+      }
+    }
+
     // Gather OS details
     const osPlatform = os.platform();
     const osArch = os.arch();

lib/setup-tofu.js

@@ -128,7 +128,8 @@ credentials "${credentialsHostname}" {
 async function run () {
   try {
     // Gather GitHub Actions inputs
-    const version = core.getInput('tofu_version');
+    let version = core.getInput('tofu_version');
+    const versionFile = core.getInput('tofu_version_file');
     const credentialsHostname = core.getInput('cli_config_credentials_hostname');
     const credentialsToken = core.getInput('cli_config_credentials_token');
     const wrapper = core.getInput('tofu_wrapper') === 'true';
@@ -139,6 +140,27 @@ async function run () {
       githubToken = process.env.GITHUB_TOKEN;
     }
 
+    // If tofu_version_file is provided, read the version from the file
+    if (versionFile) {
+      try {
+        core.debug(`Reading OpenTofu version from file: ${versionFile}`);
+        const fileVersion = await fs.readFile(versionFile, 'utf8');
+        const trimmedVersion = fileVersion.trim();
+        if (trimmedVersion) {
+          version = trimmedVersion;
+          core.debug(`Using version from file: ${version}`);
+        } else {
+          core.warning(
+            `Version file ${versionFile} is empty, using tofu_version input: ${version}`
+          );
+        }
+      } catch (error) {
+        core.warning(
+          `Failed to read version from file ${versionFile}: ${error.message}. Using tofu_version input: ${version}`
+        );
+      }
+    }
+
     // Gather OS details
     const osPlatform = os.platform();
     const osArch = os.arch();

lib/test/setup-tofu.test.js

@@ -0,0 +1,176 @@
+// Node.js core
+const fs = require('fs').promises;
+const os = require('os');
+const path = require('path');
+
+// External
+const core = require('@actions/core');
+
+// First party
+const releases = require('../releases');
+const setup = require('../setup-tofu');
+
+// Mock dependencies
+jest.mock('@actions/core');
+jest.mock('@actions/io', () => ({
+  mv: jest.fn(),
+  cp: jest.fn(),
+  mkdirP: jest.fn()
+}));
+jest.mock('@actions/tool-cache', () => ({
+  downloadTool: jest.fn(),
+  extractZip: jest.fn()
+}));
+
+// Mock releases.js so setup-tofu.js can be tested in isolation
+jest.mock('../releases');
+
+// Set up global test fixtures
+const fallbackVersion = 'latest';
+let tempDir;
+let tempDirPath;
+let version = '1.10.5';
+let versionFile;
+let versionFileName = '.opentofu-version';
+
+describe('setup-tofu', () => {
+  beforeAll(async () => {
+    // Mock dependencies
+    const tc = require('@actions/tool-cache');
+    tc.downloadTool.mockResolvedValue('/mock/download/path');
+    tc.extractZip.mockResolvedValue('/mock/extract/path');
+
+    const io = require('@actions/io');
+    io.mv.mockResolvedValue();
+    io.cp.mockResolvedValue();
+    io.mkdirP.mockResolvedValue();
+
+    const mockRelease = {
+      getBuild: jest.fn().mockReturnValue({ url: 'mock-url' })
+    };
+    releases.getRelease.mockResolvedValue(mockRelease);
+
+    // Write version file to temporary directory
+    tempDirPath = path.join(os.tmpdir(), 'setup-tofu-');
+    tempDir = await fs.mkdtemp(tempDirPath);
+    versionFile = path.join(tempDir, versionFileName);
+    await fs.writeFile(versionFile, `${version}\n`);
+
+    // Mock action inputs to return default values
+    core.getInput.mockImplementation((name) => {
+      const defaults = {
+        tofu_version: fallbackVersion,
+        tofu_version_file: versionFile,
+        cli_config_credentials_hostname: '',
+        cli_config_credentials_token: '',
+        tofu_wrapper: 'true',
+        github_token: ''
+      };
+      return defaults[name] || '';
+    });
+
+    // Mock environment variables
+    process.env.GITHUB_TOKEN = 'mock-github-token';
+  });
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  afterAll(async () => {
+    delete process.env.GITHUB_TOKEN;
+  });
+
+  describe('tofu_version_file functionality', () => {
+    it('should read version from file when tofu_version_file is provided', async () => {
+      jest.spyOn(fs, 'readFile');
+
+      await setup();
+
+      expect(releases.getRelease).toHaveBeenCalledWith(
+        version, process.env.GITHUB_TOKEN
+      );
+
+      expect(fs.readFile).toHaveBeenCalled();
+    });
+
+    it('should handle empty version file gracefully', async () => {
+      jest.spyOn(fs, 'readFile');
+
+      version = ' ';
+      versionFileName = '.opentofu-version-empty';
+      versionFile = path.join(tempDir, versionFileName);
+      await fs.writeFile(versionFile, `${version}\n`);
+
+      core.getInput.mockImplementation((name) => {
+        if (name === 'tofu_version_file') {
+          return versionFile;
+        }
+        if (name === 'tofu_version') {
+          return fallbackVersion;
+        }
+        return '';
+      });
+
+      await setup();
+
+      expect(releases.getRelease).toHaveBeenCalledWith(
+        fallbackVersion, process.env.GITHUB_TOKEN
+      );
+
+      expect(core.warning).toHaveBeenCalledWith(
+        expect.stringContaining(`Version file ${versionFile} is empty`)
+      );
+
+      expect(fs.readFile).toHaveBeenCalled();
+    });
+
+    it('should handle file read errors gracefully', async () => {
+      jest.spyOn(fs, 'readFile');
+
+      versionFileName = '.opentofu-version-file-does-not-exist';
+      versionFile = path.join(tempDir, versionFileName);
+
+      core.getInput.mockImplementation((name) => {
+        if (name === 'tofu_version_file') {
+          return versionFile;
+        }
+        if (name === 'tofu_version') {
+          return fallbackVersion;
+        }
+        return '';
+      });
+
+      await setup();
+
+      expect(releases.getRelease).toHaveBeenCalledWith(
+        fallbackVersion, process.env.GITHUB_TOKEN
+      );
+
+      expect(core.warning).toHaveBeenCalledWith(
+        expect.stringContaining(`Failed to read version from file ${versionFile}`)
+      );
+
+      expect(fs.readFile).toHaveBeenCalled();
+    });
+
+    it('should not read file when tofu_version_file is not provided', async () => {
+      jest.spyOn(fs, 'readFile');
+
+      core.getInput.mockImplementation((name) => {
+        if (name === 'tofu_version') {
+          return fallbackVersion;
+        }
+        return '';
+      });
+
+      await setup();
+
+      expect(releases.getRelease).toHaveBeenCalledWith(
+        fallbackVersion, process.env.GITHUB_TOKEN
+      );
+
+      expect(fs.readFile).not.toHaveBeenCalled();
+    });
+  });
+});