build source

vendor/k8s.io/client-go/util/workqueue/metrics.go

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+/*
+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.
+*/
+
+package workqueue
+
+import (
+	"sync"
+	"time"
+
+	"k8s.io/utils/clock"
+)
+
+// This file provides abstractions for setting the provider (e.g., prometheus)
+// of metrics.
+
+type queueMetrics[T comparable] interface {
+	add(item T)
+	get(item T)
+	done(item T)
+	updateUnfinishedWork()
+}
+
+// GaugeMetric represents a single numerical value that can arbitrarily go up
+// and down.
+type GaugeMetric interface {
+	Inc()
+	Dec()
+}
+
+// SettableGaugeMetric represents a single numerical value that can arbitrarily go up
+// and down. (Separate from GaugeMetric to preserve backwards compatibility.)
+type SettableGaugeMetric 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)
+}
+
+// HistogramMetric counts individual observations.
+type HistogramMetric interface {
+	Observe(float64)
+}
+
+type noopMetric struct{}
+
+func (noopMetric) Inc()            {}
+func (noopMetric) Dec()            {}
+func (noopMetric) Set(float64)     {}
+func (noopMetric) Observe(float64) {}
+
+// defaultQueueMetrics expects the caller to lock before setting any metrics.
+type defaultQueueMetrics[T comparable] struct {
+	clock clock.Clock
+
+	// current depth of a workqueue
+	depth GaugeMetric
+	// total number of adds handled by a workqueue
+	adds CounterMetric
+	// how long an item stays in a workqueue
+	latency HistogramMetric
+	// how long processing an item from a workqueue takes
+	workDuration         HistogramMetric
+	addTimes             map[T]time.Time
+	processingStartTimes map[T]time.Time
+
+	// how long have current threads been working?
+	unfinishedWorkSeconds   SettableGaugeMetric
+	longestRunningProcessor SettableGaugeMetric
+}
+
+func (m *defaultQueueMetrics[T]) add(item T) {
+	if m == nil {
+		return
+	}
+
+	m.adds.Inc()
+	m.depth.Inc()
+	if _, exists := m.addTimes[item]; !exists {
+		m.addTimes[item] = m.clock.Now()
+	}
+}
+
+func (m *defaultQueueMetrics[T]) get(item T) {
+	if m == nil {
+		return
+	}
+
+	m.depth.Dec()
+	m.processingStartTimes[item] = m.clock.Now()
+	if startTime, exists := m.addTimes[item]; exists {
+		m.latency.Observe(m.sinceInSeconds(startTime))
+		delete(m.addTimes, item)
+	}
+}
+
+func (m *defaultQueueMetrics[T]) done(item T) {
+	if m == nil {
+		return
+	}
+
+	if startTime, exists := m.processingStartTimes[item]; exists {
+		m.workDuration.Observe(m.sinceInSeconds(startTime))
+		delete(m.processingStartTimes, item)
+	}
+}
+
+func (m *defaultQueueMetrics[T]) updateUnfinishedWork() {
+	// Note that a summary metric would be better for this, but prometheus
+	// doesn't seem to have non-hacky ways to reset the summary metrics.
+	var total float64
+	var oldest float64
+	for _, t := range m.processingStartTimes {
+		age := m.sinceInSeconds(t)
+		total += age
+		if age > oldest {
+			oldest = age
+		}
+	}
+	m.unfinishedWorkSeconds.Set(total)
+	m.longestRunningProcessor.Set(oldest)
+}
+
+type noMetrics[T any] struct{}
+
+func (noMetrics[T]) add(item T)            {}
+func (noMetrics[T]) get(item T)            {}
+func (noMetrics[T]) done(item T)           {}
+func (noMetrics[T]) updateUnfinishedWork() {}
+
+// Gets the time since the specified start in seconds.
+func (m *defaultQueueMetrics[T]) sinceInSeconds(start time.Time) float64 {
+	return m.clock.Since(start).Seconds()
+}
+
+type retryMetrics interface {
+	retry()
+}
+
+type defaultRetryMetrics struct {
+	retries CounterMetric
+}
+
+func (m *defaultRetryMetrics) retry() {
+	if m == nil {
+		return
+	}
+
+	m.retries.Inc()
+}
+
+// MetricsProvider generates various metrics used by the queue.
+type MetricsProvider interface {
+	NewDepthMetric(name string) GaugeMetric
+	NewAddsMetric(name string) CounterMetric
+	NewLatencyMetric(name string) HistogramMetric
+	NewWorkDurationMetric(name string) HistogramMetric
+	NewUnfinishedWorkSecondsMetric(name string) SettableGaugeMetric
+	NewLongestRunningProcessorSecondsMetric(name string) SettableGaugeMetric
+	NewRetriesMetric(name string) CounterMetric
+}
+
+type noopMetricsProvider struct{}
+
+func (_ noopMetricsProvider) NewDepthMetric(name string) GaugeMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewAddsMetric(name string) CounterMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewLatencyMetric(name string) HistogramMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewWorkDurationMetric(name string) HistogramMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewUnfinishedWorkSecondsMetric(name string) SettableGaugeMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewLongestRunningProcessorSecondsMetric(name string) SettableGaugeMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewRetriesMetric(name string) CounterMetric {
+	return noopMetric{}
+}
+
+var globalMetricsProvider MetricsProvider = noopMetricsProvider{}
+
+var setGlobalMetricsProviderOnce sync.Once
+
+func newQueueMetrics[T comparable](mp MetricsProvider, name string, clock clock.Clock) queueMetrics[T] {
+	if len(name) == 0 || mp == (noopMetricsProvider{}) {
+		return noMetrics[T]{}
+	}
+	return &defaultQueueMetrics[T]{
+		clock:                   clock,
+		depth:                   mp.NewDepthMetric(name),
+		adds:                    mp.NewAddsMetric(name),
+		latency:                 mp.NewLatencyMetric(name),
+		workDuration:            mp.NewWorkDurationMetric(name),
+		unfinishedWorkSeconds:   mp.NewUnfinishedWorkSecondsMetric(name),
+		longestRunningProcessor: mp.NewLongestRunningProcessorSecondsMetric(name),
+		addTimes:                map[T]time.Time{},
+		processingStartTimes:    map[T]time.Time{},
+	}
+}
+
+func newRetryMetrics(name string, provider MetricsProvider) retryMetrics {
+	var ret *defaultRetryMetrics
+	if len(name) == 0 {
+		return ret
+	}
+
+	if provider == nil {
+		provider = globalMetricsProvider
+	}
+
+	return &defaultRetryMetrics{
+		retries: provider.NewRetriesMetric(name),
+	}
+}
+
+// SetProvider sets the metrics provider for all subsequently created work
+// queues. Only the first call has an effect.
+func SetProvider(metricsProvider MetricsProvider) {
+	setGlobalMetricsProviderOnce.Do(func() {
+		globalMetricsProvider = metricsProvider
+	})
+}