suppress health check noise (#1650)

This change suppresses logging of the Skipper health check path in normal conditions, reducing log noise.

The logging is enabled if the health check fails or debugging levels are enabled

Signed-off-by: Samuel Lang <[email protected]>

dataclients/kubernetes/kube.go

@@ -13,6 +13,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	"github.com/zalando/skipper/eskip"
+	"github.com/zalando/skipper/filters/accesslog"
 	"github.com/zalando/skipper/filters/builtin"
 	"github.com/zalando/skipper/predicates/source"
 )
@@ -348,9 +349,19 @@ func shuntRoute(r *eskip.Route) {
 }
 
 func healthcheckRoute(healthy, reverseSourcePredicate bool) *eskip.Route {
-	status := http.StatusOK
+	logFilters := []*eskip.Filter{{
+		Name: builtin.StatusName,
+		Args: []interface{}{http.StatusOK}},
+	}
 	if !healthy {
-		status = http.StatusServiceUnavailable
+		logFilters[0].Args = []interface{}{http.StatusServiceUnavailable}
+	}
+	// log if unhealthy or a debug loglevel
+	if healthy && !log.IsLevelEnabled(log.DebugLevel) {
+		logFilters = append(logFilters, &eskip.Filter{
+			Name: accesslog.DisableAccessLogName,
+			Args: []interface{}{200},
+		})
 	}
 
 	var p []*eskip.Predicate
@@ -370,11 +381,8 @@ func healthcheckRoute(healthy, reverseSourcePredicate bool) *eskip.Route {
 		Id:         healthcheckRouteID,
 		Predicates: p,
 		Path:       healthcheckPath,
-		Filters: []*eskip.Filter{{
-			Name: builtin.StatusName,
-			Args: []interface{}{status}},
-		},
-		Shunt: true,
+		Filters:    logFilters,
+		Shunt:      true,
 	}
 }