Rename health check URL parameter to path.

Also improve documentation.

docs/basics.md

@@ -236,16 +236,22 @@ For example:
       sticky = true
 ```
 
-Healthcheck URL can be configured with a relative URL for `healthcheck.URL`.
-Interval between healthcheck can be configured by using `healthcheck.interval`
-(default: 30s)
+A health check can be configured in order to remove a backend from LB rotation
+as long as it keeps returning HTTP status codes other than 200 OK to HTTP GET
+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

@@ -25,7 +25,7 @@ func GetHealthCheck() *HealthCheck {
 
 // BackendHealthCheck HealthCheck configuration for a backend
 type BackendHealthCheck struct {
-	URL          string
+	Path         string
 	Interval     time.Duration
 	DisabledURLs []*url.URL
 	lb           loadBalancer
@@ -81,7 +81,7 @@ func (hc *HealthCheck) execute(ctx context.Context) {
 					enabledURLs := currentBackend.lb.Servers()
 					var newDisabledURLs []*url.URL
 					for _, url := range currentBackend.DisabledURLs {
-						if checkHealth(url, currentBackend.URL) {
+						if checkHealth(url, currentBackend.Path) {
 							log.Debugf("HealthCheck is up [%s]: Upsert in server list", url.String())
 							currentBackend.lb.UpsertServer(url, roundrobin.Weight(1))
 						} else {
@@ -91,7 +91,7 @@ func (hc *HealthCheck) execute(ctx context.Context) {
 					currentBackend.DisabledURLs = newDisabledURLs
 
 					for _, url := range enabledURLs {
-						if !checkHealth(url, currentBackend.URL) {
+						if !checkHealth(url, currentBackend.Path) {
 							log.Debugf("HealthCheck has failed [%s]: Remove from server list", url.String())
 							currentBackend.lb.RemoveServer(url)
 							currentBackend.DisabledURLs = append(currentBackend.DisabledURLs, url)
@@ -104,12 +104,12 @@ func (hc *HealthCheck) execute(ctx context.Context) {
 	}
 }
 
-func checkHealth(serverURL *url.URL, checkURL string) bool {
+func checkHealth(serverURL *url.URL, path string) bool {
 	timeout := time.Duration(5 * time.Second)
 	client := http.Client{
 		Timeout: timeout,
 	}
-	resp, err := client.Get(serverURL.String() + checkURL)
+	resp, err := client.Get(serverURL.String() + path)
 	if err != nil || resp.StatusCode != 200 {
 		return false
 	}

server.go

@@ -666,7 +666,7 @@ 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:
@@ -700,7 +700,7 @@ 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"`
 }