feat: add API version in response header (#1216)

* feat: added stacks version in header

* fix: resolved error on reading from git-info

* fix: refactored file reading to read only once

* fix: append cors header, read .git-info only once

Co-authored-by: Rafael Cárdenas <[email protected]>

Author: MHassanTariq

src/api/init.ts

@@ -58,6 +58,9 @@ export interface ApiServer {
   forceKill: () => Promise<void>;
 }
 
+/** API version as given by .git-info */
+export const API_VERSION: { branch?: string; commit?: string; tag?: string } = {};
+
 export async function startApiServer(opts: {
   datastore: PgStore;
   writeDatastore?: PgWriteStore;
@@ -70,6 +73,15 @@ export async function startApiServer(opts: {
 }): Promise<ApiServer> {
   const { datastore, writeDatastore, chainId, serverHost, serverPort, httpLogLevel } = opts;
 
+  try {
+    const [branch, commit, tag] = fs.readFileSync('.git-info', 'utf-8').split('\n');
+    API_VERSION.branch = branch;
+    API_VERSION.commit = commit;
+    API_VERSION.tag = tag;
+  } catch (error) {
+    logger.error(`Unable to read API version from .git-info`, error);
+  }
+
   const app = express();
   const apiHost = serverHost ?? process.env['STACKS_BLOCKCHAIN_API_HOST'];
   const apiPort = serverPort ?? parseInt(process.env['STACKS_BLOCKCHAIN_API_PORT'] ?? '');
@@ -128,6 +140,15 @@ export async function startApiServer(opts: {
     });
     app.use(promMiddleware);
   }
+  // Add API version to header
+  app.use((_, res, next) => {
+    res.setHeader(
+      'X-API-Version',
+      `${API_VERSION.tag} (${API_VERSION.branch}:${API_VERSION.commit})`
+    );
+    res.append('Access-Control-Expose-Headers', 'X-API-Version');
+    next();
+  });
   // Setup request logging
   app.use(
     expressWinston.logger({

src/api/routes/status.ts

@@ -4,15 +4,15 @@ import { ServerStatusResponse } from '@stacks/stacks-blockchain-api-types';
 import { logger } from '../../helpers';
 import { getETagCacheHandler, setETagCacheHeaders } from '../controllers/cache-controller';
 import { PgStore } from '../../datastore/pg-store';
+import { API_VERSION } from '../init';
 
 export function createStatusRouter(db: PgStore): express.Router {
   const router = express.Router();
   const cacheHandler = getETagCacheHandler(db);
   const statusHandler = async (_: Request, res: any) => {
     try {
-      const [branch, commit, tag] = fs.readFileSync('.git-info', 'utf-8').split('\n');
       const response: ServerStatusResponse = {
-        server_version: `stacks-blockchain-api ${tag} (${branch}:${commit})`,
+        server_version: `stacks-blockchain-api ${API_VERSION.tag} (${API_VERSION.branch}:${API_VERSION.commit})`,
         status: 'ready',
       };
       const chainTip = await db.getUnanchoredChainTip();
@@ -28,7 +28,6 @@ export function createStatusRouter(db: PgStore): express.Router {
       setETagCacheHeaders(res);
       res.json(response);
     } catch (error) {
-      logger.error(`Unable to read git info`, error);
       const response: ServerStatusResponse = {
         status: 'ready',
       };