From 74600ffc7c7d7d8d7d2b52b255b107fd28c0eb22 Mon Sep 17 00:00:00 2001
From: Tsuyoshi-Ishikawa <tsuyozo7@gmail.com>
Date: Wed, 15 Mar 2023 22:27:18 +0900
Subject: [PATCH 1/2] enable to set worker_count to use multi_processing

---
 README.md   | 10 +++++++++-
 src/main.ts | 24 +++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 2b0e48c..ef6d3d4 100644
--- a/README.md
+++ b/README.md
@@ -275,4 +275,12 @@ The default body parse limit is 512kb.
 
 ```bash
 MAX_BODY_BYTE_SIZE=1048576 # 1048576 byte is 1MB.
-```
\ No newline at end of file
+```
+
+## Multi Processing
+If you want to build proxy in multi-process, set worker count to environment variables.
+The default worker count is 1.
+
+```bash
+CLUSTER_PROCESS=4
+```
diff --git a/src/main.ts b/src/main.ts
index fbfb42d..9d7429e 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -2,6 +2,13 @@ import { NestFactory } from '@nestjs/core';
 import { ValidationPipe } from '@nestjs/common';
 import { AppModule } from 'src/app.module';
 import { json } from 'body-parser';
+import * as _cluster from 'cluster';
+import { cpus } from 'os';
+
+const cluster = _cluster as unknown as _cluster.Cluster;
+const workerCount = process.env.CLUSTER_PROCESS
+  ? parseInt(process.env.CLUSTER_PROCESS, 10)
+  : 1;
 
 async function bootstrap() {
   const app = await NestFactory.create(AppModule);
@@ -20,4 +27,19 @@ async function bootstrap() {
   });
   await app.listen(process.env.PORT ? parseInt(process.env.PORT, 10) : 3000);
 }
-bootstrap();
+
+if (cluster.isPrimary) {
+  const workerLimit = cpus().length;
+  if (workerCount > workerLimit)
+    throw new Error(
+      `cluster process limit is ${workerLimit}. CLUSTER_PROCESS is over  ${workerLimit}`,
+    );
+
+  for (let i = 0; i < workerCount; i++) {
+    console.log('cluster fork :', i);
+    cluster.fork();
+  }
+} else {
+  console.log('worker pid is', cluster.worker?.process.pid);
+  bootstrap();
+}

From 9861c60e797da009488b3e3225c441412d5d230b Mon Sep 17 00:00:00 2001
From: Tsuyoshi-Ishikawa <tsuyozo7@gmail.com>
Date: Thu, 16 Mar 2023 12:24:26 +0900
Subject: [PATCH 2/2] restart when worker died

---
 src/main.ts | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/main.ts b/src/main.ts
index 9d7429e..364db82 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -39,6 +39,13 @@ if (cluster.isPrimary) {
     console.log('cluster fork :', i);
     cluster.fork();
   }
+
+  cluster.on('exit', (worker, code, signal) => {
+    console.log(
+      `Worker ${worker.process.pid} died with code(${code}) and signal(${signal}). Restarting...`,
+    );
+    cluster.fork();
+  });
 } else {
   console.log('worker pid is', cluster.worker?.process.pid);
   bootstrap();