add reflector metrics

Kubernetes-commit: 151d39682e62b288c247d8174a5f7fb139ee7bd1

tools/cache/BUILD

@@ -56,6 +56,7 @@ go_library(
         "mutation_cache.go",
         "mutation_detector.go",
         "reflector.go",
+        "reflector_metrics.go",
         "shared_informer.go",
         "store.go",
         "thread_safe_store.go",

tools/cache/reflector.go

@@ -48,6 +48,8 @@ import (
 type Reflector struct {
 	// name identifies this reflector. By default it will be a file:line if possible.
 	name string
+	// metrics tracks basic metric information about the reflector
+	metrics *reflectorMetrics
 
 	// The type of object we expect to place in the store.
 	expectedType reflect.Type
@@ -99,7 +101,9 @@ func NewReflector(lw ListerWatcher, expectedType interface{}, store Store, resyn
 // NewNamedReflector same as NewReflector, but with a specified name for logging
 func NewNamedReflector(name string, lw ListerWatcher, expectedType interface{}, store Store, resyncPeriod time.Duration) *Reflector {
 	r := &Reflector{
-		name:          name,
+		name: name,
+		// we need this to be unique per process (some names are still the same)but obvious who it belongs to
+		metrics:       newReflectorMetrics(makeValidPromethusMetricName(fmt.Sprintf("reflector_"+name+"_%07d", rand.Intn(1000000)))),
 		listerWatcher: lw,
 		store:         store,
 		expectedType:  reflect.TypeOf(expectedType),
@@ -110,6 +114,11 @@ func NewNamedReflector(name string, lw ListerWatcher, expectedType interface{},
 	return r
 }
 
+func makeValidPromethusMetricName(in string) string {
+	// this isn't perfect, but it removes our common characters
+	return strings.NewReplacer("/", "_", ".", "_", "-", "_").Replace(in)
+}
+
 // internalPackages are packages that ignored when creating a default reflector name. These packages are in the common
 // call chains to NewReflector, so they'd be low entropy names for reflectors
 var internalPackages = []string{"client-go/tools/cache/", "/runtime/asm_"}
@@ -231,10 +240,13 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 	// to be served from cache and potentially be delayed relative to
 	// etcd contents. Reflector framework will catch up via Watch() eventually.
 	options := metav1.ListOptions{ResourceVersion: "0"}
+	r.metrics.numberOfLists.Inc()
+	start := r.clock.Now()
 	list, err := r.listerWatcher.List(options)
 	if err != nil {
 		return fmt.Errorf("%s: Failed to list %v: %v", r.name, r.expectedType, err)
 	}
+	r.metrics.listDuration.Observe(time.Since(start).Seconds())
 	listMetaInterface, err := meta.ListAccessor(list)
 	if err != nil {
 		return fmt.Errorf("%s: Unable to understand list result %#v: %v", r.name, list, err)
@@ -244,6 +256,7 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 	if err != nil {
 		return fmt.Errorf("%s: Unable to understand list result %#v (%v)", r.name, list, err)
 	}
+	r.metrics.numberOfItemsInList.Observe(float64(len(items)))
 	if err := r.syncWith(items, resourceVersion); err != nil {
 		return fmt.Errorf("%s: Unable to sync list result: %v", r.name, err)
 	}
@@ -282,6 +295,7 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 			TimeoutSeconds: &timemoutseconds,
 		}
 
+		r.metrics.numberOfWatches.Inc()
 		w, err := r.listerWatcher.Watch(options)
 		if err != nil {
 			switch err {
@@ -333,6 +347,11 @@ func (r *Reflector) watchHandler(w watch.Interface, resourceVersion *string, err
 	// Stopping the watcher should be idempotent and if we return from this function there's no way
 	// we're coming back in with the same watch interface.
 	defer w.Stop()
+	// update metrics
+	defer func() {
+		r.metrics.numberOfItemsInWatch.Observe(float64(eventCount))
+		r.metrics.watchDuration.Observe(time.Since(start).Seconds())
+	}()
 
 loop:
 	for {
@@ -388,8 +407,8 @@ loop:
 
 	watchDuration := r.clock.Now().Sub(start)
 	if watchDuration < 1*time.Second && eventCount == 0 {
-		glog.V(4).Infof("%s: Unexpected watch close - watch lasted less than a second and no items received", r.name)
-		return errors.New("very short watch")
+		r.metrics.numberOfShortWatches.Inc()
+		return fmt.Errorf("very short watch: %s: Unexpected watch close - watch lasted less than a second and no items received", r.name)
 	}
 	glog.V(4).Infof("%s: Watch close - %v total %v items received", r.name, r.expectedType, eventCount)
 	return nil
@@ -407,4 +426,9 @@ func (r *Reflector) setLastSyncResourceVersion(v string) {
 	r.lastSyncResourceVersionMutex.Lock()
 	defer r.lastSyncResourceVersionMutex.Unlock()
 	r.lastSyncResourceVersion = v
+
+	rv, err := strconv.Atoi(v)
+	if err == nil {
+		r.metrics.lastResourceVersion.Set(float64(rv))
+	}
 }

tools/cache/reflector_metrics.go

@@ -0,0 +1,119 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// This file provides abstractions for setting the provider (e.g., prometheus)
+// of metrics.
+
+package cache
+
+import (
+	"sync"
+)
+
+// GaugeMetric represents a single numerical value that can arbitrarily go up
+// and down.
+type GaugeMetric interface {
+	Set(float64)
+}
+
+// CounterMetric represents a single numerical value that only ever
+// goes up.
+type CounterMetric interface {
+	Inc()
+}
+
+// SummaryMetric captures individual observations.
+type SummaryMetric interface {
+	Observe(float64)
+}
+
+type noopMetric struct{}
+
+func (noopMetric) Inc()            {}
+func (noopMetric) Dec()            {}
+func (noopMetric) Observe(float64) {}
+func (noopMetric) Set(float64)     {}
+
+type reflectorMetrics struct {
+	numberOfLists       CounterMetric
+	listDuration        SummaryMetric
+	numberOfItemsInList SummaryMetric
+
+	numberOfWatches      CounterMetric
+	numberOfShortWatches CounterMetric
+	watchDuration        SummaryMetric
+	numberOfItemsInWatch SummaryMetric
+
+	lastResourceVersion GaugeMetric
+}
+
+// MetricsProvider generates various metrics used by the reflector.
+type MetricsProvider interface {
+	NewListsMetric(name string) CounterMetric
+	NewListDurationMetric(name string) SummaryMetric
+	NewItemsInListMetric(name string) SummaryMetric
+
+	NewWatchesMetric(name string) CounterMetric
+	NewShortWatchesMetric(name string) CounterMetric
+	NewWatchDurationMetric(name string) SummaryMetric
+	NewItemsInWatchMetric(name string) SummaryMetric
+
+	NewLastResourceVersionMetric(name string) GaugeMetric
+}
+
+type noopMetricsProvider struct{}
+
+func (noopMetricsProvider) NewListsMetric(name string) CounterMetric         { return noopMetric{} }
+func (noopMetricsProvider) NewListDurationMetric(name string) SummaryMetric  { return noopMetric{} }
+func (noopMetricsProvider) NewItemsInListMetric(name string) SummaryMetric   { return noopMetric{} }
+func (noopMetricsProvider) NewWatchesMetric(name string) CounterMetric       { return noopMetric{} }
+func (noopMetricsProvider) NewShortWatchesMetric(name string) CounterMetric  { return noopMetric{} }
+func (noopMetricsProvider) NewWatchDurationMetric(name string) SummaryMetric { return noopMetric{} }
+func (noopMetricsProvider) NewItemsInWatchMetric(name string) SummaryMetric  { return noopMetric{} }
+func (noopMetricsProvider) NewLastResourceVersionMetric(name string) GaugeMetric {
+	return noopMetric{}
+}
+
+var metricsFactory = struct {
+	metricsProvider MetricsProvider
+	setProviders    sync.Once
+}{
+	metricsProvider: noopMetricsProvider{},
+}
+
+func newReflectorMetrics(name string) *reflectorMetrics {
+	var ret *reflectorMetrics
+	if len(name) == 0 {
+		return ret
+	}
+	return &reflectorMetrics{
+		numberOfLists:        metricsFactory.metricsProvider.NewListsMetric(name),
+		listDuration:         metricsFactory.metricsProvider.NewListDurationMetric(name),
+		numberOfItemsInList:  metricsFactory.metricsProvider.NewItemsInListMetric(name),
+		numberOfWatches:      metricsFactory.metricsProvider.NewWatchesMetric(name),
+		numberOfShortWatches: metricsFactory.metricsProvider.NewShortWatchesMetric(name),
+		watchDuration:        metricsFactory.metricsProvider.NewWatchDurationMetric(name),
+		numberOfItemsInWatch: metricsFactory.metricsProvider.NewItemsInWatchMetric(name),
+		lastResourceVersion:  metricsFactory.metricsProvider.NewLastResourceVersionMetric(name),
+	}
+}
+
+// SetReflectorMetricsProvider sets the metrics provider
+func SetReflectorMetricsProvider(metricsProvider MetricsProvider) {
+	metricsFactory.setProviders.Do(func() {
+		metricsFactory.metricsProvider = metricsProvider
+	})
+}