Expose new LocalCluster interface and use in example

build.c

@@ -9,7 +9,7 @@ int main(int argc, char **argv) {
     char *CXX = strcpy(calloc(1024, 1), or_else(getenv("CXX"), "g++"));
     char *EXEC_SUFFIX = strcpy(calloc(1024, 1), maybe(getenv("EXEC_SUFFIX")));
 
-    char *EXAMPLE_FILES[] = {"LoadBalancer", "Http3Server", "Broadcast", "HelloWorld", "Crc32", "ServerName",
+    char *EXAMPLE_FILES[] = {"HelloWorldThreaded", "Http3Server", "Broadcast", "HelloWorld", "Crc32", "ServerName",
     "EchoServer", "BroadcastingEchoServer", "UpgradeSync", "UpgradeAsync", "ParameterRoutes"};
 
     strcat(CXXFLAGS, " -march=native -O3 -Wpedantic -Wall -Wextra -Wsign-conversion -Wconversion -std=c++20 -Isrc -IuSockets/src");

examples/HelloWorldThreaded.cpp

@@ -1,40 +1,24 @@
 #include "App.h"
-#include <thread>
-#include <algorithm>
-#include <mutex>
-
-/* Note that SSL is disabled unless you build with WITH_OPENSSL=1 */
-const int SSL = 1;
-std::mutex stdoutMutex;
+#include "LocalCluster.h"
 
 int main() {
-    /* Overly simple hello world app, using multiple threads */
-    std::vector<std::thread *> threads(std::thread::hardware_concurrency());
-
-    std::transform(threads.begin(), threads.end(), threads.begin(), [](std::thread */*t*/) {
-        return new std::thread([]() {
-
-            uWS::SSLApp({
-                .key_file_name = "misc/key.pem",
-                .cert_file_name = "misc/cert.pem",
-                .passphrase = "1234"
-            }).get("/*", [](auto *res, auto * /*req*/) {
-                res->end("Hello world!");
-            }).listen(3000, [](auto *listen_socket) {
-		stdoutMutex.lock();
-                if (listen_socket) {
-                    /* Note that us_listen_socket_t is castable to us_socket_t */
-                    std::cout << "Thread " << std::this_thread::get_id() << " listening on port " << us_socket_local_port(SSL, (struct us_socket_t *) listen_socket) << std::endl;
-                } else {
-                    std::cout << "Thread " << std::this_thread::get_id() << " failed to listen on port 3000" << std::endl;
-                }
-		stdoutMutex.unlock();
-            }).run();
-
+    /* Note that SSL is disabled unless you build with WITH_OPENSSL=1 */
+    uWS::LocalCluster({
+        .key_file_name = "misc/key.pem",
+        .cert_file_name = "misc/cert.pem",
+        .passphrase = "1234"
+    },
+    [](uWS::SSLApp &app) {
+        /* Here this App instance is defined */
+        app.get("/*", [](auto *res, auto * /*req*/) {
+            res->end("Hello world!");
+        }).listen(3000, [](auto *listen_socket) {
+            if (listen_socket) {
+                /* Note that us_listen_socket_t is castable to us_socket_t */
+                std::cout << "Thread " << std::this_thread::get_id() << " listening on port " << us_socket_local_port(true, (struct us_socket_t *) listen_socket) << std::endl;
+            } else {
+                std::cout << "Thread " << std::this_thread::get_id() << " failed to listen on port 3000" << std::endl;
+            }
         });
     });
-
-    std::for_each(threads.begin(), threads.end(), [](std::thread *t) {
-        t->join();
-    });
 }

src/LocalCluster.h

@@ -0,0 +1,62 @@
+/* This header is highly experimental and needs refactorings but will do for now */
+
+#include <thread>
+#include <algorithm>
+#include <mutex>
+
+unsigned int roundRobin = 0;
+unsigned int hardwareConcurrency = std::thread::hardware_concurrency();
+std::vector<std::thread *> threads(hardwareConcurrency);
+std::vector<uWS::SSLApp *> apps;
+std::mutex m;
+
+namespace uWS {
+struct LocalCluster {
+
+    //std::vector<std::thread *> threads = std::thread::hardware_concurrency();
+    //std::vector<uWS::SSLApp *> apps;
+    //std::mutex m;
+
+
+    static void loadBalancer() {
+        static std::atomic<unsigned int> roundRobin = 0; // atomic fetch_add
+    }
+
+    LocalCluster(SocketContextOptions options = {}, std::function<void(uWS::SSLApp &)> cb = nullptr) {
+        std::transform(threads.begin(), threads.end(), threads.begin(), [options, &cb](std::thread *) {
+
+            return new std::thread([options, &cb]() {
+
+                // lock this
+                m.lock();
+                apps.emplace_back(new uWS::SSLApp(options));
+                uWS::SSLApp *app = apps.back();
+
+                cb(*app);
+
+                app->preOpen([](LIBUS_SOCKET_DESCRIPTOR fd) {
+
+                    /* Distribute this socket in round robin fashion */
+                    //std::cout << "About to load balance " << fd << " to " << roundRobin << std::endl;
+
+                    auto receivingApp = apps[roundRobin];
+                    apps[roundRobin]->getLoop()->defer([fd, receivingApp]() {
+                        receivingApp->adoptSocket(fd);
+                    });
+
+                    roundRobin = (roundRobin + 1) % hardwareConcurrency;
+                    return -1;
+                });
+                m.unlock();
+                app->run();
+                std::cout << "Fallthrough!" << std::endl;
+                delete app;
+            });
+        });
+
+        std::for_each(threads.begin(), threads.end(), [](std::thread *t) {
+            t->join();
+        });
+    }
+};
+}