Matteo Scandolo | a428586 | 2020-12-01 18:10:10 -0800 | [diff] [blame^] | 1 | /* |
| 2 | Copyright 2016 The Kubernetes Authors. |
| 3 | |
| 4 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | you may not use this file except in compliance with the License. |
| 6 | You may obtain a copy of the License at |
| 7 | |
| 8 | http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | |
| 10 | Unless required by applicable law or agreed to in writing, software |
| 11 | distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | See the License for the specific language governing permissions and |
| 14 | limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package workqueue |
| 18 | |
| 19 | import ( |
| 20 | "sync" |
| 21 | "time" |
| 22 | |
| 23 | "k8s.io/apimachinery/pkg/util/clock" |
| 24 | ) |
| 25 | |
| 26 | // This file provides abstractions for setting the provider (e.g., prometheus) |
| 27 | // of metrics. |
| 28 | |
| 29 | type queueMetrics interface { |
| 30 | add(item t) |
| 31 | get(item t) |
| 32 | done(item t) |
| 33 | updateUnfinishedWork() |
| 34 | } |
| 35 | |
| 36 | // GaugeMetric represents a single numerical value that can arbitrarily go up |
| 37 | // and down. |
| 38 | type GaugeMetric interface { |
| 39 | Inc() |
| 40 | Dec() |
| 41 | } |
| 42 | |
| 43 | // SettableGaugeMetric represents a single numerical value that can arbitrarily go up |
| 44 | // and down. (Separate from GaugeMetric to preserve backwards compatibility.) |
| 45 | type SettableGaugeMetric interface { |
| 46 | Set(float64) |
| 47 | } |
| 48 | |
| 49 | // CounterMetric represents a single numerical value that only ever |
| 50 | // goes up. |
| 51 | type CounterMetric interface { |
| 52 | Inc() |
| 53 | } |
| 54 | |
| 55 | // SummaryMetric captures individual observations. |
| 56 | type SummaryMetric interface { |
| 57 | Observe(float64) |
| 58 | } |
| 59 | |
| 60 | // HistogramMetric counts individual observations. |
| 61 | type HistogramMetric interface { |
| 62 | Observe(float64) |
| 63 | } |
| 64 | |
| 65 | type noopMetric struct{} |
| 66 | |
| 67 | func (noopMetric) Inc() {} |
| 68 | func (noopMetric) Dec() {} |
| 69 | func (noopMetric) Set(float64) {} |
| 70 | func (noopMetric) Observe(float64) {} |
| 71 | |
| 72 | // defaultQueueMetrics expects the caller to lock before setting any metrics. |
| 73 | type defaultQueueMetrics struct { |
| 74 | clock clock.Clock |
| 75 | |
| 76 | // current depth of a workqueue |
| 77 | depth GaugeMetric |
| 78 | // total number of adds handled by a workqueue |
| 79 | adds CounterMetric |
| 80 | // how long an item stays in a workqueue |
| 81 | latency HistogramMetric |
| 82 | // how long processing an item from a workqueue takes |
| 83 | workDuration HistogramMetric |
| 84 | addTimes map[t]time.Time |
| 85 | processingStartTimes map[t]time.Time |
| 86 | |
| 87 | // how long have current threads been working? |
| 88 | unfinishedWorkSeconds SettableGaugeMetric |
| 89 | longestRunningProcessor SettableGaugeMetric |
| 90 | } |
| 91 | |
| 92 | func (m *defaultQueueMetrics) add(item t) { |
| 93 | if m == nil { |
| 94 | return |
| 95 | } |
| 96 | |
| 97 | m.adds.Inc() |
| 98 | m.depth.Inc() |
| 99 | if _, exists := m.addTimes[item]; !exists { |
| 100 | m.addTimes[item] = m.clock.Now() |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | func (m *defaultQueueMetrics) get(item t) { |
| 105 | if m == nil { |
| 106 | return |
| 107 | } |
| 108 | |
| 109 | m.depth.Dec() |
| 110 | m.processingStartTimes[item] = m.clock.Now() |
| 111 | if startTime, exists := m.addTimes[item]; exists { |
| 112 | m.latency.Observe(m.sinceInSeconds(startTime)) |
| 113 | delete(m.addTimes, item) |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | func (m *defaultQueueMetrics) done(item t) { |
| 118 | if m == nil { |
| 119 | return |
| 120 | } |
| 121 | |
| 122 | if startTime, exists := m.processingStartTimes[item]; exists { |
| 123 | m.workDuration.Observe(m.sinceInSeconds(startTime)) |
| 124 | delete(m.processingStartTimes, item) |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | func (m *defaultQueueMetrics) updateUnfinishedWork() { |
| 129 | // Note that a summary metric would be better for this, but prometheus |
| 130 | // doesn't seem to have non-hacky ways to reset the summary metrics. |
| 131 | var total float64 |
| 132 | var oldest float64 |
| 133 | for _, t := range m.processingStartTimes { |
| 134 | age := m.sinceInSeconds(t) |
| 135 | total += age |
| 136 | if age > oldest { |
| 137 | oldest = age |
| 138 | } |
| 139 | } |
| 140 | m.unfinishedWorkSeconds.Set(total) |
| 141 | m.longestRunningProcessor.Set(oldest) |
| 142 | } |
| 143 | |
| 144 | type noMetrics struct{} |
| 145 | |
| 146 | func (noMetrics) add(item t) {} |
| 147 | func (noMetrics) get(item t) {} |
| 148 | func (noMetrics) done(item t) {} |
| 149 | func (noMetrics) updateUnfinishedWork() {} |
| 150 | |
| 151 | // Gets the time since the specified start in seconds. |
| 152 | func (m *defaultQueueMetrics) sinceInSeconds(start time.Time) float64 { |
| 153 | return m.clock.Since(start).Seconds() |
| 154 | } |
| 155 | |
| 156 | type retryMetrics interface { |
| 157 | retry() |
| 158 | } |
| 159 | |
| 160 | type defaultRetryMetrics struct { |
| 161 | retries CounterMetric |
| 162 | } |
| 163 | |
| 164 | func (m *defaultRetryMetrics) retry() { |
| 165 | if m == nil { |
| 166 | return |
| 167 | } |
| 168 | |
| 169 | m.retries.Inc() |
| 170 | } |
| 171 | |
| 172 | // MetricsProvider generates various metrics used by the queue. |
| 173 | type MetricsProvider interface { |
| 174 | NewDepthMetric(name string) GaugeMetric |
| 175 | NewAddsMetric(name string) CounterMetric |
| 176 | NewLatencyMetric(name string) HistogramMetric |
| 177 | NewWorkDurationMetric(name string) HistogramMetric |
| 178 | NewUnfinishedWorkSecondsMetric(name string) SettableGaugeMetric |
| 179 | NewLongestRunningProcessorSecondsMetric(name string) SettableGaugeMetric |
| 180 | NewRetriesMetric(name string) CounterMetric |
| 181 | } |
| 182 | |
| 183 | type noopMetricsProvider struct{} |
| 184 | |
| 185 | func (_ noopMetricsProvider) NewDepthMetric(name string) GaugeMetric { |
| 186 | return noopMetric{} |
| 187 | } |
| 188 | |
| 189 | func (_ noopMetricsProvider) NewAddsMetric(name string) CounterMetric { |
| 190 | return noopMetric{} |
| 191 | } |
| 192 | |
| 193 | func (_ noopMetricsProvider) NewLatencyMetric(name string) HistogramMetric { |
| 194 | return noopMetric{} |
| 195 | } |
| 196 | |
| 197 | func (_ noopMetricsProvider) NewWorkDurationMetric(name string) HistogramMetric { |
| 198 | return noopMetric{} |
| 199 | } |
| 200 | |
| 201 | func (_ noopMetricsProvider) NewUnfinishedWorkSecondsMetric(name string) SettableGaugeMetric { |
| 202 | return noopMetric{} |
| 203 | } |
| 204 | |
| 205 | func (_ noopMetricsProvider) NewLongestRunningProcessorSecondsMetric(name string) SettableGaugeMetric { |
| 206 | return noopMetric{} |
| 207 | } |
| 208 | |
| 209 | func (_ noopMetricsProvider) NewRetriesMetric(name string) CounterMetric { |
| 210 | return noopMetric{} |
| 211 | } |
| 212 | |
| 213 | var globalMetricsFactory = queueMetricsFactory{ |
| 214 | metricsProvider: noopMetricsProvider{}, |
| 215 | } |
| 216 | |
| 217 | type queueMetricsFactory struct { |
| 218 | metricsProvider MetricsProvider |
| 219 | |
| 220 | onlyOnce sync.Once |
| 221 | } |
| 222 | |
| 223 | func (f *queueMetricsFactory) setProvider(mp MetricsProvider) { |
| 224 | f.onlyOnce.Do(func() { |
| 225 | f.metricsProvider = mp |
| 226 | }) |
| 227 | } |
| 228 | |
| 229 | func (f *queueMetricsFactory) newQueueMetrics(name string, clock clock.Clock) queueMetrics { |
| 230 | mp := f.metricsProvider |
| 231 | if len(name) == 0 || mp == (noopMetricsProvider{}) { |
| 232 | return noMetrics{} |
| 233 | } |
| 234 | return &defaultQueueMetrics{ |
| 235 | clock: clock, |
| 236 | depth: mp.NewDepthMetric(name), |
| 237 | adds: mp.NewAddsMetric(name), |
| 238 | latency: mp.NewLatencyMetric(name), |
| 239 | workDuration: mp.NewWorkDurationMetric(name), |
| 240 | unfinishedWorkSeconds: mp.NewUnfinishedWorkSecondsMetric(name), |
| 241 | longestRunningProcessor: mp.NewLongestRunningProcessorSecondsMetric(name), |
| 242 | addTimes: map[t]time.Time{}, |
| 243 | processingStartTimes: map[t]time.Time{}, |
| 244 | } |
| 245 | } |
| 246 | |
| 247 | func newRetryMetrics(name string) retryMetrics { |
| 248 | var ret *defaultRetryMetrics |
| 249 | if len(name) == 0 { |
| 250 | return ret |
| 251 | } |
| 252 | return &defaultRetryMetrics{ |
| 253 | retries: globalMetricsFactory.metricsProvider.NewRetriesMetric(name), |
| 254 | } |
| 255 | } |
| 256 | |
| 257 | // SetProvider sets the metrics provider for all subsequently created work |
| 258 | // queues. Only the first call has an effect. |
| 259 | func SetProvider(metricsProvider MetricsProvider) { |
| 260 | globalMetricsFactory.setProvider(metricsProvider) |
| 261 | } |