From 47a90eef81608322674c6fbe398730f423d2d8c5 Mon Sep 17 00:00:00 2001
From: Joeky <joeky5888@gmail.com>
Date: Fri, 17 Mar 2023 23:15:50 +0800
Subject: [PATCH] Add thread pool

Signed-off-by: Joeky <joeky5888@gmail.com>
---
 main.go | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/main.go b/main.go
index 311d399..77f1a4d 100644
--- a/main.go
+++ b/main.go
@@ -9,6 +9,14 @@ import (
 	"time"
 )
 
+var poolGuard chan struct{}
+
+const MaxGoroutine = 512
+
+func init() {
+	poolGuard = make(chan struct{}, MaxGoroutine)
+}
+
 func handleTunneling(w http.ResponseWriter, r *http.Request) {
 	destConn, err := net.DialTimeout("tcp", r.Host, 10*time.Second)
 	if err != nil {
@@ -59,10 +67,20 @@ func copyHeader(dst, src http.Header) {
 	}
 }
 
+func acquireRequestPool() {
+	poolGuard <- struct{}{} // Would block if guard channel is full
+}
+
+func releaseRequestPool() {
+	<-poolGuard
+}
+
 func main() {
 	server := &http.Server{
 		Addr: ":13002",
 		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			acquireRequestPool()
+			defer releaseRequestPool()
 			if r.Method == http.MethodConnect {
 				handleTunneling(w, r)
 			} else {