feat(main): add cluster

Author: tugascript

src/cluster.ts

@@ -0,0 +1,60 @@
+/*
+ This file is part of Nest GraphQL Fastify Template
+
+ This project is dual-licensed under the Mozilla Public License 2.0 (MPLv2) and the
+ GNU General Public License version 3 (GPLv3).
+
+ You may use, distribute, and modify this file under the terms of either the MPLv2
+ or GPLv3, at your option. If a copy of these licenses was not distributed with this
+ file. You may obtain a copy of the licenses at https://www.mozilla.org/en-US/MPL/2.0/
+ and https://www.gnu.org/licenses/gpl-3.0.en.html respectively.
+
+ Copyright © 2023
+ Afonso Barracha
+*/
+
+import { Logger } from '@nestjs/common';
+import cluster from 'cluster';
+import os from 'os';
+import { isUndefined } from './config/utils/validation.util';
+
+export class Cluster {
+  private static readonly loggerService = new Logger(Cluster.name);
+
+  public static createCluster(main: () => Promise<void>): void {
+    const cpuCount = Cluster.getCpuCount();
+
+    if (cluster.isMaster) {
+      Cluster.loggerService.log(`Starting cluster with ${cpuCount} workers...`);
+      Cluster.loggerService.log(
+        `Master server is running on process ${process.pid}`,
+      );
+
+      for (let i = 0; i < cpuCount; i++) {
+        Cluster.loggerService.log(`Forking process number ${i + 1}...`);
+        cluster.fork();
+      }
+
+      cluster.on('exit', (worker) => {
+        Cluster.loggerService.warn(`Worker ${worker.id} died. `);
+        Cluster.loggerService.warn('Starting a new worker...');
+        cluster.fork();
+      });
+    } else {
+      main();
+    }
+  }
+
+  private static getCpuCount(): number {
+    if (!isUndefined(process.env.WORKERS_COUNT)) {
+      return parseInt(process.env.WORKERS_COUNT, 10);
+    }
+    if (
+      !isUndefined(process.env.NODE_ENV) &&
+      process.env.NODE_ENV === 'production'
+    ) {
+      return os.cpus().length;
+    }
+    return 2;
+  }
+}

src/config/validation.config.ts

@@ -57,4 +57,5 @@ export const validationSchema = Joi.object({
   FACEBOOK_CLIENT_SECRET: Joi.string().optional(),
   GITHUB_CLIENT_ID: Joi.string().optional(),
   GITHUB_CLIENT_SECRET: Joi.string().optional(),
+  WORKERS_COUNT: Joi.number().optional(),
 });

src/main.ts

@@ -28,6 +28,7 @@ import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
 import mercuriusUpload from 'mercurius-upload';
 import { join } from 'path';
 import { AppModule } from './app.module';
+import { Cluster } from './cluster';
 
 async function bootstrap(): Promise<void> {
   const app = await NestFactory.create<NestFastifyApplication>(
@@ -68,4 +69,4 @@ async function bootstrap(): Promise<void> {
   );
 }
 
-bootstrap();
+Cluster.createCluster(bootstrap);