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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/apimachinery/pkg/util/clock"
)
// This file provides abstractions for setting the provider (e.g., prometheus)
// of metrics.
type queueMetrics 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 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) 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) 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) 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) 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 struct{}
func (noMetrics) add(item t) {}
func (noMetrics) get(item t) {}
func (noMetrics) done(item t) {}
func (noMetrics) updateUnfinishedWork() {}
// Gets the time since the specified start in seconds.
func (m *defaultQueueMetrics) 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 globalMetricsFactory = queueMetricsFactory{
metricsProvider: noopMetricsProvider{},
}
type queueMetricsFactory struct {
metricsProvider MetricsProvider
onlyOnce sync.Once
}
func (f *queueMetricsFactory) setProvider(mp MetricsProvider) {
f.onlyOnce.Do(func() {
f.metricsProvider = mp
})
}
func (f *queueMetricsFactory) newQueueMetrics(name string, clock clock.Clock) queueMetrics {
mp := f.metricsProvider
if len(name) == 0 || mp == (noopMetricsProvider{}) {
return noMetrics{}
}
return &defaultQueueMetrics{
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) retryMetrics {
var ret *defaultRetryMetrics
if len(name) == 0 {
return ret
}
return &defaultRetryMetrics{
retries: globalMetricsFactory.metricsProvider.NewRetriesMetric(name),
}
}
// SetProvider sets the metrics provider for all subsequently created work
// queues. Only the first call has an effect.
func SetProvider(metricsProvider MetricsProvider) {
globalMetricsFactory.setProvider(metricsProvider)
}