Gracefull shutdown WEB UI microservice

msa/web-ui/docker/start-web-ui.sh

@@ -26,4 +26,5 @@ source "${CONF_FOLDER}/${configfile}"
 
 cd ${pkg.installFolder}
 
-exec /bin/sh -c "node server.js"
+# This will forward this PID 1 to the node.js and forward SIGTERM for graceful shutdown as well
+exec node server.js

msa/web-ui/server.ts

@@ -22,10 +22,12 @@ import http, { ServerResponse } from 'http';
 import httpProxy from 'http-proxy';
 import compression from 'compression';
 import historyApiFallback from 'connect-history-api-fallback';
+import { Socket } from 'net';
 
 const logger = _logger('main');
 
 let server: http.Server | null;
+let connections: Socket[] = [];
 
 (async() => {
     try {
@@ -102,34 +104,51 @@ let server: http.Server | null;
         server.listen(bindPort, bindAddress, () => {
             logger.info('==> 🌎  Listening on port %s.', bindPort);
             logger.info('Started ThingsBoard Web UI Microservice.');
-        }).on('error', (error) => {
+        }).on('error', async (error) => {
             logger.error('Failed to start ThingsBoard Web UI Microservice: %s', error.message);
             logger.error(error.stack);
-            exit(-1);
+            await exit(-1);
+        });
+
+        server.on('connection', connection => {
+            connections.push(connection);
+            connection.on('close', () => connections = connections.filter(curr => curr !== connection));
         });
 
     } catch (e: any) {
         logger.error('Failed to start ThingsBoard Web UI Microservice: %s', e.message);
         logger.error(e.stack);
-        exit(-1);
+        await exit(-1);
     }
 })();
 
-process.on('exit', () => {
+[`SIGINT`, `SIGUSR1`, `SIGUSR2`, `uncaughtException`, `SIGTERM`].forEach((eventType) => {
-    exit(0);
+    process.on(eventType, async () => {
+        logger.info(`${eventType} signal received`);
+        await exit(0);
+    });
+})
+
+process.on('exit', async (code: number) => {
+    logger.info(`ThingsBoard Web UI Microservice has been stopped. Exit code: ${code}.`);
 });
 
-function exit(status: number) {
+async function exit(status: number) {
     logger.info('Exiting with status: %d ...', status);
     if (server) {
         logger.info('Stopping HTTP Server...');
+        connections.forEach(curr => curr.end(() => curr.destroy()));
         const _server = server;
         server = null;
-        _server.close(() => {
+        const serverClosePromise = new Promise<void>(
+            (resolve, reject) => {
+                _server.close((err) => {
                     logger.info('HTTP Server stopped.');
-            process.exit(status);
+                    resolve();
                 });
-    } else {
+            }
+        );
+        await serverClosePromise;
+    }
     process.exit(status);
 }
-}