From: Urban Wallasch <urban.wallasch@freenet.de>
Date: Wed, 10 Apr 2019 17:06:01 +0000 (+0200)
Subject: * Added connection accept rate throttling and worker job queue based request handling.
X-Git-Url: https://git.packet-gain.de/?a=commitdiff_plain;h=e26ddcf101e3e332cb342f4ed19e916b56d580b4;p=gogopherd.git

* Added connection accept rate throttling and worker job queue based request handling.
---

diff --git a/gogopherd.go b/gogopherd.go
index 4cf1c28..0b029db 100644
--- a/gogopherd.go
+++ b/gogopherd.go
@@ -248,6 +248,34 @@ func handleRequest(conn net.Conn) {
 }
 
 func serveTCP(listener *net.TCPListener) {
+	// connection rate limiter
+	rate := 5
+	burst := 50
+	interval := time.Second / time.Duration(rate)
+	tick := time.NewTicker(interval)
+	defer tick.Stop()
+	throttle := make(chan time.Time, burst)
+	go func() {
+		for t := range tick.C {
+			select {
+			case throttle <- t:
+			default:
+			}
+		}
+	}()
+	// worker and job queue setup
+	nworker := 5
+	njobs := 50
+	jobs := make(chan net.Conn, njobs)
+	for w := 1; w <= nworker; w++ {
+		go func(id int, jobs <-chan net.Conn) {
+			for j := range jobs {
+				tracer.Print("worker id ", id, ": ", j.RemoteAddr())
+				handleRequest(j)
+			}
+		}(w, jobs)
+	}
+	// accept connections
 	defer listener.Close()
 	logger.Print("listening on TCP ", listener.Addr())
 	for {
@@ -257,8 +285,9 @@ func serveTCP(listener *net.TCPListener) {
 		}
 		if checkFatal(err, "Accept") == nil {
 			logger.Print("connect from ", conn.RemoteAddr())
-			go handleRequest(conn)
+			jobs <- conn
 		}
+		<-throttle
 	}
 }