From 882afa4163789da997bbccada062248f7dd004bd Mon Sep 17 00:00:00 2001
From: Gregor Noczinski <gregor@noczinski.eu>
Date: Thu, 10 Sep 2020 14:25:59 +0200
Subject: [PATCH] Make SO_LINGER configurable

---
 server/connections.go    | 8 +++++---
 server/connector_http.go | 8 +++++++-
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/server/connections.go b/server/connections.go
index 38a0423..a333c88 100644
--- a/server/connections.go
+++ b/server/connections.go
@@ -8,18 +8,20 @@ import (
 )
 
 type limitedListener struct {
+	linger int16
 	sync.Mutex
 	net.Listener
 	sem chan bool
 }
 
-func newLimitedListener(count uint16, l net.Listener) *limitedListener {
+func newLimitedListener(count uint16, linger int16, l net.Listener) *limitedListener {
 	sem := make(chan bool, count)
 	for i := uint16(0); i < count; i++ {
 		sem <- true
 	}
 	return &limitedListener{
 		Listener: l,
+		linger:   linger,
 		sem:      sem,
 	}
 }
@@ -35,8 +37,8 @@ func (instance *limitedListener) Accept() (net.Conn, error) {
 	if c, err := instance.Listener.Accept(); err != nil {
 		return nil, err
 	} else {
-		if err := c.(*net.TCPConn).SetLinger(0); err != nil {
-			return nil, fmt.Errorf("cannot set the SO_LINGER to 0")
+		if err := c.(*net.TCPConn).SetLinger(int(instance.linger)); err != nil {
+			return nil, fmt.Errorf("cannot set the SO_LINGER to %d", instance.linger)
 		}
 		result := &limitedConn{
 			Conn:                c,
diff --git a/server/connector_http.go b/server/connector_http.go
index 16fcb69..ac14a2b 100644
--- a/server/connector_http.go
+++ b/server/connector_http.go
@@ -15,6 +15,7 @@ type HttpConnector struct {
 	Id      ConnectorId
 	Handler ConnectorHandler
 
+	SoLinger       int16
 	MaxConnections uint16
 
 	Server       http.Server
@@ -25,6 +26,7 @@ func NewHttpConnector(id ConnectorId) (*HttpConnector, error) {
 	result := HttpConnector{
 		Id:             id,
 		MaxConnections: 512,
+		SoLinger:       -1,
 
 		Server: http.Server{
 			Addr:              ":8080",
@@ -53,7 +55,7 @@ func (instance *HttpConnector) Serve(stop support.Channel) error {
 	if err != nil {
 		return err
 	}
-	ln = newLimitedListener(instance.MaxConnections, ln)
+	ln = newLimitedListener(instance.MaxConnections, instance.SoLinger, ln)
 
 	var serve func() error
 	if tlsConfig := instance.Server.TLSConfig; tlsConfig != nil {
@@ -121,6 +123,10 @@ func (instance *HttpConnector) RegisterFlag(fe support.FlagEnabled, appPrefix st
 		PlaceHolder(fmt.Sprint(instance.MaxConnections)).
 		Envar(instance.serverFlagEnvVar(appPrefix, "MAX_CONNECTIONS")).
 		Uint16Var(&instance.MaxConnections)
+	fe.Flag(instance.serverFlagName("soLinger"), "Set the behavior of SO_LINGER.").
+		PlaceHolder(fmt.Sprint(instance.SoLinger)).
+		Envar(instance.serverFlagEnvVar(appPrefix, "SO_LINGER")).
+		Int16Var(&instance.SoLinger)
 
 	fe.Flag(instance.clientFlagName("maxHeaderBytes"), "Maximum number of bytes the server will read parsing the request header's keys and values, including the request line. It does not limit the size of the request body.").
 		PlaceHolder(fmt.Sprint(instance.Server.MaxHeaderBytes)).