Rename health check URL parameter to path.

Also improve documentation.

docs/basics.md

@@ -240,16 +240,22 @@ For example:
       sticky = true
 ```
 
-Healthcheck URL can be configured with a relative URL for `healthcheck.URL`.
+A health check can be configured in order to remove a backend from LB rotation
-Interval between healthcheck can be configured by using `healthcheck.interval`
+as long as it keeps returning HTTP status codes other than 200 OK to HTTP GET
-(default: 30s)
+requests periodically carried out by Traefik. The check is defined by a path
+appended to the backend URL and an interval (given in a format understood by [time.ParseDuration](https://golang.org/pkg/time/#ParseDuration)) specifying how
+often the health check should be executed (the default being 30 seconds). Each
+backend must respond to the health check within 5 seconds.
+
+A recovering backend returning 200 OK responses again is being returned to the
+LB rotation pool.
 
 For example:
 ```toml
 [backends]
   [backends.backend1]
     [backends.backend1.healthcheck]
-      URL = "/health"
+      path = "/health"
       interval = "10s"
 ```
 

healthcheck/healthcheck.go

@@ -25,11 +25,11 @@ func GetHealthCheck() *HealthCheck {
 
 // BackendHealthCheck HealthCheck configuration for a backend
 type BackendHealthCheck struct {
-	URL            string
+	Path         string
-	Interval       time.Duration
+	Interval     time.Duration
-	DisabledURLs   []*url.URL
+	DisabledURLs []*url.URL
 	requestTimeout time.Duration
-	lb             loadBalancer
+	lb           loadBalancer
 }
 
 var launch = false
@@ -85,12 +85,12 @@ func (hc *HealthCheck) execute(ctx context.Context, backendID string, backend *B
 	checkBackend(backend)
 	ticker := time.NewTicker(backend.Interval)
 	defer ticker.Stop()
-	for {
+			for {
-		select {
+				select {
-		case <-ctx.Done():
+				case <-ctx.Done():
-			log.Debugf("Stopping all current Healthcheck goroutines")
+					log.Debugf("Stopping all current Healthcheck goroutines")
-			return
+					return
-		case <-ticker.C:
+				case <-ticker.C:
 			log.Debugf("Refreshing healthcheck for currentBackend %s ", backendID)
 			checkBackend(backend)
 		}
@@ -98,33 +98,33 @@ func (hc *HealthCheck) execute(ctx context.Context, backendID string, backend *B
 }
 
 func checkBackend(currentBackend *BackendHealthCheck) {
-	enabledURLs := currentBackend.lb.Servers()
+					enabledURLs := currentBackend.lb.Servers()
-	var newDisabledURLs []*url.URL
+					var newDisabledURLs []*url.URL
-	for _, url := range currentBackend.DisabledURLs {
+					for _, url := range currentBackend.DisabledURLs {
 		if checkHealth(url, currentBackend) {
-			log.Debugf("HealthCheck is up [%s]: Upsert in server list", url.String())
+							log.Debugf("HealthCheck is up [%s]: Upsert in server list", url.String())
-			currentBackend.lb.UpsertServer(url, roundrobin.Weight(1))
+							currentBackend.lb.UpsertServer(url, roundrobin.Weight(1))
-		} else {
+						} else {
 			log.Warnf("HealthCheck is still failing [%s]", url.String())
-			newDisabledURLs = append(newDisabledURLs, url)
+							newDisabledURLs = append(newDisabledURLs, url)
-		}
+						}
-	}
+					}
-	currentBackend.DisabledURLs = newDisabledURLs
+					currentBackend.DisabledURLs = newDisabledURLs
 
-	for _, url := range enabledURLs {
+					for _, url := range enabledURLs {
 		if !checkHealth(url, currentBackend) {
 			log.Warnf("HealthCheck has failed [%s]: Remove from server list", url.String())
-			currentBackend.lb.RemoveServer(url)
+							currentBackend.lb.RemoveServer(url)
-			currentBackend.DisabledURLs = append(currentBackend.DisabledURLs, url)
+							currentBackend.DisabledURLs = append(currentBackend.DisabledURLs, url)
-		}
+						}
-	}
+					}
 }
 
 func checkHealth(serverURL *url.URL, backend *BackendHealthCheck) bool {
 	client := http.Client{
 		Timeout: backend.requestTimeout,
 	}
-	resp, err := client.Get(serverURL.String() + backend.URL)
+	resp, err := client.Get(serverURL.String() + backend.Path)
 	if err == nil {
 		defer resp.Body.Close()
 	}

server.go

@@ -667,7 +667,7 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 											interval = time.Second * 30
 										}
 									}
-									backendsHealthcheck[frontend.Backend] = healthcheck.NewBackendHealthCheck(configuration.Backends[frontend.Backend].HealthCheck.URL, interval, rebalancer)
+									backendsHealthcheck[frontend.Backend] = healthcheck.NewBackendHealthCheck(configuration.Backends[frontend.Backend].HealthCheck.Path, interval, rebalancer)
 								}
 							}
 						case types.Wrr:
@@ -701,7 +701,7 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 										interval = time.Second * 30
 									}
 								}
-								backendsHealthcheck[frontend.Backend] = healthcheck.NewBackendHealthCheck(configuration.Backends[frontend.Backend].HealthCheck.URL, interval, rr)
+								backendsHealthcheck[frontend.Backend] = healthcheck.NewBackendHealthCheck(configuration.Backends[frontend.Backend].HealthCheck.Path, interval, rr)
 							}
 						}
 						maxConns := configuration.Backends[frontend.Backend].MaxConn

types/types.go

@@ -39,7 +39,7 @@ type CircuitBreaker struct {
 
 // HealthCheck holds HealthCheck configuration
 type HealthCheck struct {
-	URL      string `json:"url,omitempty"`
+	Path     string `json:"path,omitempty"`
 	Interval string `json:"interval,omitempty"`
 }