admin, reverseproxy: Stop timers if canceled to avoid goroutine leak (#…

…4482)

caddy.go

@@ -494,16 +494,21 @@ 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))
 							return
 						}
 						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
 					}

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
 	}
 }