1/* 2Copyright 2016 The Kubernetes Authors. 3 4Licensed under the Apache License, Version 2.0 (the "License"); 5you may not use this file except in compliance with the License. 6You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10Unless required by applicable law or agreed to in writing, software 11distributed under the License is distributed on an "AS IS" BASIS, 12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13See the License for the specific language governing permissions and 14limitations under the License. 15*/ 16 17// This file provides abstractions for setting the provider (e.g., prometheus) 18// of metrics. 19 20package cache 21 22import ( 23 "sync" 24) 25 26// GaugeMetric represents a single numerical value that can arbitrarily go up 27// and down. 28type GaugeMetric interface { 29 Set(float64) 30} 31 32// CounterMetric represents a single numerical value that only ever 33// goes up. 34type CounterMetric interface { 35 Inc() 36} 37 38// SummaryMetric captures individual observations. 39type SummaryMetric interface { 40 Observe(float64) 41} 42 43type noopMetric struct{} 44 45func (noopMetric) Inc() {} 46func (noopMetric) Dec() {} 47func (noopMetric) Observe(float64) {} 48func (noopMetric) Set(float64) {} 49 50// MetricsProvider generates various metrics used by the reflector. 51type 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 64type noopMetricsProvider struct{} 65 66func (noopMetricsProvider) NewListsMetric(name string) CounterMetric { return noopMetric{} } 67func (noopMetricsProvider) NewListDurationMetric(name string) SummaryMetric { return noopMetric{} } 68func (noopMetricsProvider) NewItemsInListMetric(name string) SummaryMetric { return noopMetric{} } 69func (noopMetricsProvider) NewWatchesMetric(name string) CounterMetric { return noopMetric{} } 70func (noopMetricsProvider) NewShortWatchesMetric(name string) CounterMetric { return noopMetric{} } 71func (noopMetricsProvider) NewWatchDurationMetric(name string) SummaryMetric { return noopMetric{} } 72func (noopMetricsProvider) NewItemsInWatchMetric(name string) SummaryMetric { return noopMetric{} } 73func (noopMetricsProvider) NewLastResourceVersionMetric(name string) GaugeMetric { 74 return noopMetric{} 75} 76 77var metricsFactory = struct { 78 metricsProvider MetricsProvider 79 setProviders sync.Once 80}{ 81 metricsProvider: noopMetricsProvider{}, 82} 83 84// SetReflectorMetricsProvider sets the metrics provider 85func SetReflectorMetricsProvider(metricsProvider MetricsProvider) { 86 metricsFactory.setProviders.Do(func() { 87 metricsFactory.metricsProvider = metricsProvider 88 }) 89} 90