techdocs: Add build timestamp to techdocs_metadata.json

Co-authored-by: Raghunandan Balachandran <soapraj@gmail.com>

packages/techdocs-common/src/stages/generate/helpers.test.ts

@@ -13,22 +13,23 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import fs from 'fs-extra';
-import os from 'os';
-import { resolve as resolvePath } from 'path';
-import Stream, { PassThrough } from 'stream';
+import { getVoidLogger } from '@backstage/backend-common';
 import Docker from 'dockerode';
+import fs from 'fs-extra';
 import mockFs from 'mock-fs';
-import * as winston from 'winston';
-import {
-  runDockerContainer,
-  getGeneratorKey,
-  isValidRepoUrlForMkdocs,
-  getRepoUrlFromLocationAnnotation,
-  patchMkdocsYmlPreBuild,
-} from './helpers';
-import { RemoteProtocol } from '../prepare/types';
+import os from 'os';
+import path, { resolve as resolvePath } from 'path';
+import Stream, { PassThrough } from 'stream';
 import { ParsedLocationAnnotation } from '../../helpers';
+import { RemoteProtocol } from '../prepare/types';
+import {
+  addBuildTimestampMetadata,
+  getGeneratorKey,
+  getRepoUrlFromLocationAnnotation,
+  isValidRepoUrlForMkdocs,
+  patchMkdocsYmlPreBuild,
+  runDockerContainer,
+} from './helpers';
 
 const mockEntity = {
   apiVersion: 'version',
@@ -46,7 +47,8 @@ const mkdocsYml = fs.readFileSync(
 const mkdocsYmlWithRepoUrl = fs.readFileSync(
   resolvePath(__filename, '../__fixtures__/mkdocs_with_repo_url.yml'),
 );
-const mockLogger = winston.createLogger();
+const mockLogger = getVoidLogger();
+const tmpDir = os.platform() === 'win32' ? 'C:\\tmp' : '/tmp';
 
 describe('helpers', () => {
   describe('getGeneratorKey', () => {
@@ -329,4 +331,47 @@ describe('helpers', () => {
       );
     });
   });
+
+  describe('addBuildTimestampMetadata', () => {
+    beforeEach(() => {
+      mockFs({
+        [tmpDir]: {
+          'invalid_techdocs_metadata.json': 'dsds',
+          'techdocs_metadata.json': '{"site_name": "Tech Docs"}',
+        },
+      });
+    });
+
+    afterEach(() => {
+      mockFs.restore();
+    });
+
+    it('should create the file if it does not exist', async () => {
+      const filePath = path.join(tmpDir, 'wrong_techdocs_metadata.json');
+      await addBuildTimestampMetadata(filePath, mockLogger);
+
+      // Check if the file exists
+      await expect(
+        fs.access(filePath, fs.constants.F_OK),
+      ).resolves.not.toThrowError();
+    });
+
+    it('should throw error when the JSON is invalid', async () => {
+      const filePath = path.join(tmpDir, 'invalid_techdocs_metadata.json');
+
+      // Check if the file exists
+      await expect(
+        addBuildTimestampMetadata(filePath, mockLogger),
+      ).rejects.toThrowError();
+    });
+
+    it('should add build timestamp to the metadata json', async () => {
+      const filePath = path.join(tmpDir, 'techdocs_metadata.json');
+
+      await addBuildTimestampMetadata(filePath, mockLogger);
+
+      const json = await fs.readJson(filePath);
+      expect(json.build_timestamp).toBeLessThanOrEqual(Date.now());
+    });
+  });
 });

packages/techdocs-common/src/stages/generate/helpers.ts

@@ -14,16 +14,16 @@
  * limitations under the License.
  */
 
-import fs from 'fs-extra';
-import { spawn } from 'child_process';
-import { Writable, PassThrough } from 'stream';
-import Docker from 'dockerode';
-import yaml from 'js-yaml';
-import { Logger } from 'winston';
 import { Entity } from '@backstage/catalog-model';
-import { SupportedGeneratorKey } from './types';
+import { spawn } from 'child_process';
+import Docker from 'dockerode';
+import fs from 'fs-extra';
+import yaml from 'js-yaml';
+import { PassThrough, Writable } from 'stream';
+import { Logger } from 'winston';
 import { ParsedLocationAnnotation } from '../../helpers';
 import { RemoteProtocol } from '../prepare/types';
+import { SupportedGeneratorKey } from './types';
 
 // TODO: Implement proper support for more generators.
 export function getGeneratorKey(entity: Entity): SupportedGeneratorKey {
@@ -275,3 +275,34 @@ export const patchMkdocsYmlPreBuild = async (
     return;
   }
 };
+
+/**
+ * Update the techdocs_metadata.json to add a new build timestamp metadata. Create the .json file if it doesn't exist.
+ *
+ * @param {string} techdocsMetadataPath File path to techdocs_metadata.json
+ */
+export const addBuildTimestampMetadata = async (
+  techdocsMetadataPath: string,
+  logger: Logger,
+): Promise<void> => {
+  // check if file exists, create if it does not.
+  try {
+    await fs.access(techdocsMetadataPath, fs.constants.F_OK);
+  } catch (err) {
+    // Bootstrap file with empty JSON
+    await fs.writeJson(techdocsMetadataPath, JSON.parse('{}'));
+  }
+  // check if valid Json
+  let json;
+  try {
+    json = await fs.readJson(techdocsMetadataPath);
+  } catch (err) {
+    const message = `Invalid JSON at ${techdocsMetadataPath} with error ${err.message}`;
+    logger.error(message);
+    throw new Error(message);
+  }
+
+  json.build_timestamp = Date.now();
+  await fs.writeJson(techdocsMetadataPath, json);
+  return;
+};

packages/techdocs-common/src/stages/generate/techdocs.ts

@@ -14,17 +14,17 @@
  * limitations under the License.
  */
 
-import path from 'path';
-import { Logger } from 'winston';
-import { PassThrough } from 'stream';
 import { Config } from '@backstage/config';
-
-import { GeneratorBase, GeneratorRunOptions } from './types';
+import path from 'path';
+import { PassThrough } from 'stream';
+import { Logger } from 'winston';
 import {
-  runDockerContainer,
-  runCommand,
+  addBuildTimestampMetadata,
   patchMkdocsYmlPreBuild,
+  runCommand,
+  runDockerContainer,
 } from './helpers';
+import { GeneratorBase, GeneratorRunOptions } from './types';
 
 type TechdocsGeneratorOptions = {
   // This option enables users to configure if they want to use TechDocs container
@@ -118,5 +118,13 @@ export class TechdocsGenerator implements GeneratorBase {
         `Failed to generate docs from ${inputDir} into ${outputDir} with error ${error.message}`,
       );
     }
+
+    // Post Generate steps
+
+    // Add build timestamp to techdocs_metadata.json
+    addBuildTimestampMetadata(
+      path.join(outputDir, 'techdocs_metadata.json'),
+      this.logger,
+    );
   }
 }