✨ feat(versionfile): accept versionfile

dist/index.js

@@ -120,11 +120,48 @@ credentials "${credentialsHostname}" {
   core.debug(`Adding credentials to ${credsFile}`);
   await fs.writeFile(credsFile, creds);
 }
+async function isVersionFileExist(versionFilePath) {
+  try {
+    await fs.access(versionFilePath);
+    return true;
+  } catch (err) {
+    return false;
+  }
+}
+async function resolveVersionInput() {
+  let version = core.getInput("terraform_version");
+  const versionFileInput = core.getInput("terraform_version_file");
+  if (version && versionFileInput) {
+    core.warning(
+      "Both terraform_version and terraform_version_file inputs are specified, only terraform_version will be used"
+    );
+  }
+  if (version) {
+    return version;
+  }
+  if (versionFileInput) {
+    const versionFilePath = path.join(
+      process.env.GITHUB_WORKSPACE,
+      versionFileInput
+    );
+    const fileExists = await isVersionFileExist(versionFilePath);
+    if (!fileExists) {
+      throw new Error(
+        `The specified terraform version file at: ${versionFilePath} does not exist`
+      );
+    }
+
+    version = await fs.readFile(versionFilePath, "utf-8");
+
+    core.info(`Resolved ${versionFileInput} as ${version}`);
+  }
+  return version || "latest";
+}
 
 async function run () {
   try {
     // Gather GitHub Actions inputs
-    const version = core.getInput('terraform_version');
+    const version = await resolveVersionInput();
     const credentialsHostname = core.getInput('cli_config_credentials_hostname');
     const credentialsToken = core.getInput('cli_config_credentials_token');
     const wrapper = core.getInput('terraform_wrapper') === 'true';