k8s.io/client-go@v0.31.1/tools/cache/reflector_metrics.go (about) 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 // This file provides abstractions for setting the provider (e.g., prometheus) 18 // of metrics. 19 20 package cache 21 22 import ( 23 "sync" 24 ) 25 26 // GaugeMetric represents a single numerical value that can arbitrarily go up 27 // and down. 28 type GaugeMetric interface { 29 Set(float64) 30 } 31 32 // CounterMetric represents a single numerical value that only ever 33 // goes up. 34 type CounterMetric interface { 35 Inc() 36 } 37 38 // SummaryMetric captures individual observations. 39 type SummaryMetric interface { 40 Observe(float64) 41 } 42 43 type noopMetric struct{} 44 45 func (noopMetric) Inc() {} 46 func (noopMetric) Dec() {} 47 func (noopMetric) Observe(float64) {} 48 func (noopMetric) Set(float64) {} 49 50 // MetricsProvider generates various metrics used by the reflector. 51 type MetricsProvider interface { 52 NewListsMetric(name string) CounterMetric 53 NewListDurationMetric(name string) SummaryMetric 54 NewItemsInListMetric(name string) SummaryMetric 55 56 NewWatchesMetric(name string) CounterMetric 57 NewShortWatchesMetric(name string) CounterMetric 58 NewWatchDurationMetric(name string) SummaryMetric 59 NewItemsInWatchMetric(name string) SummaryMetric 60 61 NewLastResourceVersionMetric(name string) GaugeMetric 62 } 63 64 type noopMetricsProvider struct{} 65 66 func (noopMetricsProvider) NewListsMetric(name string) CounterMetric { return noopMetric{} } 67 func (noopMetricsProvider) NewListDurationMetric(name string) SummaryMetric { return noopMetric{} } 68 func (noopMetricsProvider) NewItemsInListMetric(name string) SummaryMetric { return noopMetric{} } 69 func (noopMetricsProvider) NewWatchesMetric(name string) CounterMetric { return noopMetric{} } 70 func (noopMetricsProvider) NewShortWatchesMetric(name string) CounterMetric { return noopMetric{} } 71 func (noopMetricsProvider) NewWatchDurationMetric(name string) SummaryMetric { return noopMetric{} } 72 func (noopMetricsProvider) NewItemsInWatchMetric(name string) SummaryMetric { return noopMetric{} } 73 func (noopMetricsProvider) NewLastResourceVersionMetric(name string) GaugeMetric { 74 return noopMetric{} 75 } 76 77 var metricsFactory = struct { 78 metricsProvider MetricsProvider 79 setProviders sync.Once 80 }{ 81 metricsProvider: noopMetricsProvider{}, 82 } 83 84 // SetReflectorMetricsProvider sets the metrics provider 85 func SetReflectorMetricsProvider(metricsProvider MetricsProvider) { 86 metricsFactory.setProviders.Do(func() { 87 metricsFactory.metricsProvider = metricsProvider 88 }) 89 }