From 99ffc26d4082d84c751cd9085f30fe2c1311a7ce Mon Sep 17 00:00:00 2001
From: Julien Salleyron <juliens@php.net>
Date: Wed, 30 Nov 2016 22:49:57 +0100
Subject: [PATCH] One goroutine for each backend + fix typo

---
 healthcheck/healthcheck.go | 64 +++++++++++++++++++++++---------------
 server.go                  |  8 ++---
 2 files changed, 43 insertions(+), 29 deletions(-)

diff --git a/healthcheck/healthcheck.go b/healthcheck/healthcheck.go
index a8b0de4fc..ebf0cac8a 100644
--- a/healthcheck/healthcheck.go
+++ b/healthcheck/healthcheck.go
@@ -1,6 +1,7 @@
 package healthcheck
 
 import (
+	"context"
 	"github.com/containous/traefik/log"
 	"github.com/vulcand/oxy/roundrobin"
 	"net/http"
@@ -16,7 +17,6 @@ var once sync.Once
 func GetHealthCheck() *HealthCheck {
 	once.Do(func() {
 		singleton = newHealthCheck()
-		singleton.execute()
 	})
 	return singleton
 }
@@ -33,6 +33,7 @@ var launch = false
 //HealthCheck struct
 type HealthCheck struct {
 	Backends map[string]*BackendHealthCheck
+	cancel   context.CancelFunc
 }
 
 type loadBalancer interface {
@@ -42,7 +43,7 @@ type loadBalancer interface {
 }
 
 func newHealthCheck() *HealthCheck {
-	return &HealthCheck{make(map[string]*BackendHealthCheck)}
+	return &HealthCheck{make(map[string]*BackendHealthCheck), nil}
 }
 
 // NewBackendHealthCheck Instantiate a new BackendHealthCheck
@@ -53,36 +54,49 @@ func NewBackendHealthCheck(URL string, lb loadBalancer) *BackendHealthCheck {
 //SetBackendsConfiguration set backends configuration
 func (hc *HealthCheck) SetBackendsConfiguration(backends map[string]*BackendHealthCheck) {
 	hc.Backends = backends
+	if hc.cancel != nil {
+		hc.cancel()
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	hc.cancel = cancel
+	hc.execute(ctx)
 }
 
-func (hc *HealthCheck) execute() {
-	ticker := time.NewTicker(time.Second * 30)
-	go func() {
-		for t := range ticker.C {
-			for backendID, backend := range hc.Backends {
-				log.Debugf("Refreshing Healthcheck %s for backend %s ", t.String(), backendID)
-				enabledURLs := backend.lb.Servers()
-				var newDisabledURLs []*url.URL
-				for _, url := range backend.DisabledURLs {
-					if testHealth(url, backend.URL) {
-						log.Debugf("Upsert %s", url.String())
-						backend.lb.UpsertServer(url, roundrobin.Weight(1))
-					} else {
-						newDisabledURLs = append(newDisabledURLs, url)
+func (hc *HealthCheck) execute(ctx context.Context) {
+	for backendID, backend := range hc.Backends {
+		go func(backendID string, backend *BackendHealthCheck) {
+			for {
+				ticker := time.NewTicker(time.Second * 30)
+				select {
+				case <-ctx.Done():
+					log.Debugf("Refreshing All Healthcheck goroutines")
+					return
+				case <-ticker.C:
+					log.Debugf("Refreshing Healthcheck for backend %s ", backendID)
+					enabledURLs := backend.lb.Servers()
+					var newDisabledURLs []*url.URL
+					for _, url := range backend.DisabledURLs {
+						if testHealth(url, backend.URL) {
+							log.Debugf("Upsert %s", url.String())
+							backend.lb.UpsertServer(url, roundrobin.Weight(1))
+						} else {
+							newDisabledURLs = append(newDisabledURLs, url)
+						}
 					}
-				}
-				backend.DisabledURLs = newDisabledURLs
+					backend.DisabledURLs = newDisabledURLs
 
-				for _, url := range enabledURLs {
-					if !testHealth(url, backend.URL) {
-						log.Debugf("Remove %s", url.String())
-						backend.lb.RemoveServer(url)
-						backend.DisabledURLs = append(backend.DisabledURLs, url)
+					for _, url := range enabledURLs {
+						if !testHealth(url, backend.URL) {
+							log.Debugf("Remove %s", url.String())
+							backend.lb.RemoveServer(url)
+							backend.DisabledURLs = append(backend.DisabledURLs, url)
+						}
 					}
+
 				}
 			}
-		}
-	}()
+		}(backendID, backend)
+	}
 }
 
 func testHealth(serverURL *url.URL, checkURL string) bool {
diff --git a/server.go b/server.go
index b968a30bf..499a9a706 100644
--- a/server.go
+++ b/server.go
@@ -553,7 +553,7 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 
 	backends := map[string]http.Handler{}
 
-	backendsHealcheck := map[string]*healthcheck.BackendHealthCheck{}
+	backendsHealthcheck := map[string]*healthcheck.BackendHealthCheck{}
 
 	backend2FrontendMap := map[string]string{}
 	for _, configuration := range configurations {
@@ -655,7 +655,7 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 									continue frontend
 								}
 								if configuration.Backends[frontend.Backend].HealthCheck != nil {
-									backendsHealcheck[frontend.Backend] = healthcheck.NewBackendHealthCheck(configuration.Backends[frontend.Backend].HealthCheck.URL, rebalancer)
+									backendsHealthcheck[frontend.Backend] = healthcheck.NewBackendHealthCheck(configuration.Backends[frontend.Backend].HealthCheck.URL, rebalancer)
 								}
 							}
 						case types.Wrr:
@@ -681,7 +681,7 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 								}
 							}
 							if configuration.Backends[frontend.Backend].HealthCheck != nil {
-								backendsHealcheck[frontend.Backend] = healthcheck.NewBackendHealthCheck(configuration.Backends[frontend.Backend].HealthCheck.URL, rr)
+								backendsHealthcheck[frontend.Backend] = healthcheck.NewBackendHealthCheck(configuration.Backends[frontend.Backend].HealthCheck.URL, rr)
 							}
 						}
 						maxConns := configuration.Backends[frontend.Backend].MaxConn
@@ -745,7 +745,7 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 			}
 		}
 	}
-	healthcheck.GetHealthCheck().SetBackendsConfiguration(backendsHealcheck)
+	healthcheck.GetHealthCheck().SetBackendsConfiguration(backendsHealthcheck)
 	middlewares.SetBackend2FrontendMap(&backend2FrontendMap)
 	//sort routes
 	for _, serverEntryPoint := range serverEntryPoints {