Add healthcheck for each express instance.

controllers/routes.js

@@ -321,8 +321,9 @@ export function bindRoutes(app) {
     });
 
     // Ping-pong to verify the server is working
-    app.all('/ping', (req, res) => {
-        res.status(200).send('pong');
+    app.all('/health', (req, res) => {
+        res.set('Cache-Control', 'no-store');
+        res.status(200).send('OK');
     });
 
     // Last handler. If request reaches it, means that there is no handler for this request

downloader.js

@@ -302,6 +302,14 @@ export async function configure(startStamp) {
     // Start server and do manual manual url router, express is not needed
     const server = http
         .createServer(function handleRequest(req, res) {
+            if (req.url === '/health') {
+                res.setHeader('Cache-Control', 'no-store');
+                res.statusCode = 200;
+                res.end('OK');
+
+                return;
+            }
+
             if (protectedServePattern.test(req.url)) {
                 return protectedHandler(req, res);
             }

uploader.js

@@ -268,6 +268,14 @@ export function configure(startStamp) {
     };
 
     const handleRequest = (req, res) => {
+        if (req.url === '/health') {
+            res.setHeader('Cache-Control', 'no-store');
+            res.statusCode = 200;
+            res.end('OK');
+
+            return;
+        }
+
         if (req.url !== '/upload' && req.url !== '/uploadava') {
             res.statusCode = 403;
             res.end();