/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// This file provides abstractions for setting the provider (e.g., prometheus)
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// of metrics.
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package cache
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import (
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"sync"
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)
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// GaugeMetric represents a single numerical value that can arbitrarily go up
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// and down.
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type GaugeMetric interface {
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Set(float64)
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}
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// CounterMetric represents a single numerical value that only ever
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// goes up.
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type CounterMetric interface {
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Inc()
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}
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// SummaryMetric captures individual observations.
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type SummaryMetric interface {
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Observe(float64)
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}
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type noopMetric struct{}
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func (noopMetric) Inc() {}
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func (noopMetric) Dec() {}
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func (noopMetric) Observe(float64) {}
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func (noopMetric) Set(float64) {}
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// MetricsProvider generates various metrics used by the reflector.
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type MetricsProvider interface {
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NewListsMetric(name string) CounterMetric
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NewListDurationMetric(name string) SummaryMetric
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NewItemsInListMetric(name string) SummaryMetric
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NewWatchesMetric(name string) CounterMetric
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NewShortWatchesMetric(name string) CounterMetric
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NewWatchDurationMetric(name string) SummaryMetric
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NewItemsInWatchMetric(name string) SummaryMetric
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NewLastResourceVersionMetric(name string) GaugeMetric
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}
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type noopMetricsProvider struct{}
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func (noopMetricsProvider) NewListsMetric(name string) CounterMetric { return noopMetric{} }
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func (noopMetricsProvider) NewListDurationMetric(name string) SummaryMetric { return noopMetric{} }
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func (noopMetricsProvider) NewItemsInListMetric(name string) SummaryMetric { return noopMetric{} }
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func (noopMetricsProvider) NewWatchesMetric(name string) CounterMetric { return noopMetric{} }
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func (noopMetricsProvider) NewShortWatchesMetric(name string) CounterMetric { return noopMetric{} }
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func (noopMetricsProvider) NewWatchDurationMetric(name string) SummaryMetric { return noopMetric{} }
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func (noopMetricsProvider) NewItemsInWatchMetric(name string) SummaryMetric { return noopMetric{} }
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func (noopMetricsProvider) NewLastResourceVersionMetric(name string) GaugeMetric {
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return noopMetric{}
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}
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var metricsFactory = struct {
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metricsProvider MetricsProvider
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setProviders sync.Once
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}{
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metricsProvider: noopMetricsProvider{},
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}
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// SetReflectorMetricsProvider sets the metrics provider
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func SetReflectorMetricsProvider(metricsProvider MetricsProvider) {
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metricsFactory.setProviders.Do(func() {
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metricsFactory.metricsProvider = metricsProvider
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})
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}
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