New WorkerThread.js apporoach using addChildApp

examples/WorkerThreads.js

@@ -1,33 +1,61 @@
-/* This example spawns two worker threads, each with their own
- * server listening to the same port (Linux feature). */
+/* This example shows two different approaches to multi-core load balancing.
+ * The first approach (the oldest) requires Linux and will only work on Linux.
+ * This approach listens to port 4000 on all CPUs. That's it. That's all you do.
+ * Listening to the same port from many worker threads will work on Linux.
+ * The second approach will work on all platforms; you set up a main acceptorApp and register all child apps
+ * (worker apps) with it. The acceptorApp will listen to port 9001 and move sockets in round-robin fashion to
+ * the registered child apps.
+ * Note that, in this example we only create 2 worker threads. Ideally you should create as many as there are CPUs
+ * in your system. But by only creating 2 here, it is simple to see the perf. gain on a system of 4 cores, as you can then
+ * run the client side on the remaining 2 cores without interfering with the server side. */
 
 const uWS = require('../dist/uws.js');
 const port = 9001;
-const { Worker, isMainThread, threadId } = require('worker_threads');
+const { Worker, isMainThread, threadId, parentPort } = require('worker_threads');
 const os = require('os');
 
 if (isMainThread) {
+
+	/* The acceptorApp only listens, but must be SSL if worker apps are SSL and likewise opposite */
+	const acceptorApp = uWS./*SSL*/App({
+		key_file_name: 'misc/key.pem',
+		cert_file_name: 'misc/cert.pem',
+		passphrase: '1234'
+	  }).listen(port, (token) => {
+		if (token) {
+		  console.log('Listening to port ' + port + ' from thread ' + threadId + ' as main acceptor');
+		} else {
+		  console.log('Failed to listen to port ' + port + ' from thread ' + threadId);
+		}
+	  });
+
   /* Main thread loops over all CPUs */
   /* In this case we only spawn two (hardcoded) */
   /*os.cpus()*/[0, 1].forEach(() => {
+
     /* Spawn a new thread running this source file */
-    new Worker(__filename);
+    new Worker(__filename).on("message", (workerAppDescriptor) => {
+		acceptorApp.addChildAppDescriptor(workerAppDescriptor);
+	});
   });
 
   /* I guess main thread joins by default? */
 } else {
   /* Here we are inside a worker thread */
-  const app = uWS.SSLApp({
+  const app = uWS./*SSL*/App({
     key_file_name: 'misc/key.pem',
     cert_file_name: 'misc/cert.pem',
     passphrase: '1234'
   }).get('/*', (res, req) => {
     res.end('Hello Worker!');
-  }).listen(port, (token) => {
-    if (token) {
-      console.log('Listening to port ' + port + ' from thread ' + threadId);
-    } else {
-      console.log('Failed to listen to port ' + port + ' from thread ' + threadId);
-    }
+  }).listen(4000, (token) => {
+	if (token) {
+		console.log('Listening to port ' + 4000 + ' from thread ' + threadId);
+	  } else {
+		console.log('Failed to listen to port ' + 4000 + ' from thread ' + threadId);
+	  }
   });
+
+  /* The worker sends back its descriptor to the main acceptor */
+  parentPort.postMessage(app.getDescriptor());
 }

src/AppWrapper.h

@@ -713,6 +713,54 @@ std::pair<uWS::SocketContextOptions, bool> readOptionsObject(const FunctionCallb
     return {options, true};
 }
 
+template <typename APP>
+void uWS_App_addChildApp(const FunctionCallbackInfo<Value> &args) {
+    APP *app = (APP *) args.Holder()->GetAlignedPointerFromInternalField(0);
+
+    Isolate *isolate = args.GetIsolate();
+
+    double descriptor = args[0]->NumberValue(isolate->GetCurrentContext()).ToChecked();
+
+
+    APP *receivingApp;// = (APP *) args[0]->ToObject(isolate->GetCurrentContext()).ToLocalChecked()->GetAlignedPointerFromInternalField(0);
+
+    memcpy(&receivingApp, &descriptor, sizeof(receivingApp));
+
+    /* Todo: check the class type of args[0] must match class type of args.Holder() */
+    //if (args[0])
+
+    //std::cout << "addChildApp: " << receivingApp << std::endl;
+
+    app->addChildApp(receivingApp);
+
+    args.GetReturnValue().Set(args.Holder());
+}
+
+template <typename APP>
+void uWS_App_getDescriptor(const FunctionCallbackInfo<Value> &args) {
+    APP *app = (APP *) args.Holder()->GetAlignedPointerFromInternalField(0);
+
+    Isolate *isolate = args.GetIsolate();
+
+    static_assert(sizeof(double) >= sizeof(app));
+
+    //static thread_local std::unordered_set<UniquePersistent<Object>> persistentApps;
+
+    UniquePersistent<Object> *persistentApp = new UniquePersistent<Object>;
+    persistentApp->Reset(args.GetIsolate(), args.Holder());
+
+    //persistentApps.emplace(persistentApp);
+
+    double descriptor = 0;
+    memcpy(&descriptor, &app, sizeof(app));
+
+    //std::cout << "getDescriptor: " << app << std::endl;
+
+    //std::cout << "Loop: " << app->getLoop() << std::endl;
+
+    args.GetReturnValue().Set(Number::New(isolate, descriptor));
+}
+
 template <typename APP>
 void uWS_App_addServerName(const FunctionCallbackInfo<Value> &args) {
     APP *app = (APP *) args.Holder()->GetAlignedPointerFromInternalField(0);
@@ -920,6 +968,11 @@ void uWS_App(const FunctionCallbackInfo<Value> &args) {
         appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "listen_unix", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_listen_unix<APP>, args.Data()));
         appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "filter", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_filter<APP>, args.Data()));
 
+        /* load balancing */
+        appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "addChildAppDescriptor", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_addChildApp<APP>, args.Data()));
+        appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "getDescriptor", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_getDescriptor<APP>, args.Data()));
+
+
         /* ws, listen */
         appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "ws", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_ws<APP>, args.Data()));
         appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "publish", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_publish<APP>, args.Data()));