From 2e46c2ac1d860230a80de5fd7bc85c8c9429d3f4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=94=D0=B5=D0=BD=D0=B8=D1=81=20=D0=A2=D0=B5=D0=BB=D1=8E?=
 =?UTF-8?q?=D1=85?= <telyukh.denis@gmail.com>
Date: Wed, 5 Jan 2022 02:14:18 +0700
Subject: [PATCH] admin, reverseproxy: Stop timers if canceled to avoid
 goroutine leak (#4482)

---
 caddy.go                                       | 7 ++++++-
 modules/caddyhttp/reverseproxy/reverseproxy.go | 7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/caddy.go b/caddy.go
index bee4274c7d3..f990d362cfa 100644
--- a/caddy.go
+++ b/caddy.go
@@ -494,9 +494,10 @@ func finishSettingUp(ctx Context, cfg *Config) error {
 		if cfg.Admin.Config.LoadInterval > 0 {
 			go func() {
 				for {
+					timer := time.NewTimer(time.Duration(cfg.Admin.Config.LoadInterval))
 					select {
 					// if LoadInterval is positive, will wait for the interval and then run with new config
-					case <-time.After(time.Duration(cfg.Admin.Config.LoadInterval)):
+					case <-timer.C:
 						loadedConfig, err := val.(ConfigLoader).LoadConfig(ctx)
 						if err != nil {
 							Log().Error("loading dynamic config failed", zap.Error(err))
@@ -504,6 +505,10 @@ func finishSettingUp(ctx Context, cfg *Config) error {
 						}
 						runLoadedConfig(loadedConfig)
 					case <-ctx.Done():
+						if !timer.Stop() {
+							// if the timer has been stopped then read from the channel
+							<-timer.C
+						}
 						Log().Info("stopping config load interval")
 						return
 					}
diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go
index b4189535fd9..eaa7cbf928e 100644
--- a/modules/caddyhttp/reverseproxy/reverseproxy.go
+++ b/modules/caddyhttp/reverseproxy/reverseproxy.go
@@ -792,10 +792,15 @@ func (lb LoadBalancing) tryAgain(ctx caddy.Context, start time.Time, proxyErr er
 	}
 
 	// otherwise, wait and try the next available host
+	timer := time.NewTimer(time.Duration(lb.TryInterval))
 	select {
-	case <-time.After(time.Duration(lb.TryInterval)):
+	case <-timer.C:
 		return true
 	case <-ctx.Done():
+		if !timer.Stop() {
+			// if the timer has been stopped then read from the channel
+			<-timer.C
+		}
 		return false
 	}
 }