Readiness probe health check

controllers/gce/controller/utils.go

@@ -27,6 +27,7 @@ import (
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/apis/extensions"
 	"k8s.io/kubernetes/pkg/client/cache"
+	"k8s.io/kubernetes/pkg/labels"
 	"k8s.io/kubernetes/pkg/util/intstr"
 	"k8s.io/kubernetes/pkg/util/sets"
 	"k8s.io/kubernetes/pkg/util/wait"
@@ -357,3 +358,98 @@ func (t *GCETranslator) ListZones() ([]string, error) {
 	}
 	return zones.List(), nil
 }
+
+// isPortEqual compares the given IntOrString ports
+func isPortEqual(port, targetPort intstr.IntOrString) bool {
+	if targetPort.Type == intstr.Int {
+		return port.IntVal == targetPort.IntVal
+	}
+	return port.StrVal == targetPort.StrVal
+}
+
+// geHTTPProbe returns the http readiness probe from the first container
+// that matches targetPort, from the set of pods matching the given labels.
+func (t *GCETranslator) getHTTPProbe(l map[string]string, targetPort intstr.IntOrString) (*api.Probe, error) {
+	// Lookup any container with a matching targetPort from the set of pods
+	// with a matching label selector.
+	pl, err := t.podLister.List(labels.SelectorFromSet(labels.Set(l)))
+	if err != nil {
+		return nil, err
+	}
+	for _, pod := range pl {
+		logStr := fmt.Sprintf("Pod %v matching service selectors %v (targetport %+v)", pod.Name, l, targetPort)
+		for _, c := range pod.Spec.Containers {
+			if c.ReadinessProbe == nil || c.ReadinessProbe.Handler.HTTPGet == nil {
+				continue
+			}
+			for _, p := range c.Ports {
+				cPort := intstr.IntOrString{IntVal: p.ContainerPort, StrVal: p.Name}
+				if isPortEqual(cPort, targetPort) {
+					if isPortEqual(c.ReadinessProbe.Handler.HTTPGet.Port, targetPort) {
+						return c.ReadinessProbe, nil
+					} else {
+						glog.Infof("%v: found matching targetPort on container %v, but not on readinessProbe (%+v)",
+							logStr, c.Name, c.ReadinessProbe.Handler.HTTPGet.Port)
+					}
+				}
+			}
+		}
+		glog.V(4).Infof("%v: lacks a matching HTTP probe for use in health checks.", logStr)
+	}
+	return nil, nil
+}
+
+// HealthCheck returns the http readiness probe for the endpoint backing the
+// given nodePort. If no probe is found it returns a health check with "" as
+// the request path, callers are responsible for swapping this out for the
+// appropriate default.
+func (t *GCETranslator) HealthCheck(port int64) (*compute.HttpHealthCheck, error) {
+	sl, err := t.svcLister.List()
+	if err != nil {
+		return nil, err
+	}
+	// Find the label and target port of the one service with the given nodePort
+	for _, s := range sl.Items {
+		for _, p := range s.Spec.Ports {
+			if int32(port) == p.NodePort {
+				rp, err := t.getHTTPProbe(s.Spec.Selector, p.TargetPort)
+				if err != nil {
+					return nil, err
+				}
+				if rp == nil {
+					glog.Infof("No pod in service %v with node port %v has declared a matching readiness probe for health checks.", s.Name, port)
+					break
+				}
+				healthPath := rp.Handler.HTTPGet.Path
+				host := rp.Handler.HTTPGet.Host
+				glog.Infof("Found custom health check for Service %v nodeport %v: %v%v", s.Name, port, host, healthPath)
+				return &compute.HttpHealthCheck{
+					Port:               port,
+					RequestPath:        healthPath,
+					Host:               host,
+					Description:        "kubernetes L7 health check from readiness probe.",
+					CheckIntervalSec:   int64(rp.PeriodSeconds),
+					TimeoutSec:         int64(rp.TimeoutSeconds),
+					HealthyThreshold:   int64(rp.SuccessThreshold),
+					UnhealthyThreshold: int64(rp.FailureThreshold),
+					// TODO: include headers after updating compute godep.
+				}, nil
+			}
+		}
+	}
+	return &compute.HttpHealthCheck{
+		Port: port,
+		// Empty string is used as a signal to the caller to use the appropriate
+		// default.
+		RequestPath: "",
+		Description: "Default kubernetes L7 Loadbalancing health check.",
+		// How often to health check.
+		CheckIntervalSec: 1,
+		// How long to wait before claiming failure of a health check.
+		TimeoutSec: 1,
+		// Number of healthchecks to pass for a vm to be deemed healthy.
+		HealthyThreshold: 1,
+		// Number of healthchecks to fail before the vm is deemed unhealthy.
+		UnhealthyThreshold: 10,
+	}, nil
+}