mirror of
https://github.com/kubernetes-sigs/prometheus-adapter.git
synced 2026-04-05 17:27:51 +00:00
295 lines
9.1 KiB
Go
295 lines
9.1 KiB
Go
/*
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Copyright 2017 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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package provider
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import (
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"context"
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"fmt"
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"math"
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"time"
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pmodel "github.com/prometheus/common/model"
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apierr "k8s.io/apimachinery/pkg/api/errors"
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apimeta "k8s.io/apimachinery/pkg/api/meta"
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"k8s.io/apimachinery/pkg/api/resource"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/labels"
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"k8s.io/apimachinery/pkg/types"
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utilruntime "k8s.io/apimachinery/pkg/util/runtime"
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"k8s.io/apimachinery/pkg/util/wait"
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"k8s.io/client-go/dynamic"
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"k8s.io/klog/v2"
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"k8s.io/metrics/pkg/apis/custom_metrics"
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"sigs.k8s.io/custom-metrics-apiserver/pkg/provider"
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"sigs.k8s.io/custom-metrics-apiserver/pkg/provider/helpers"
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prom "sigs.k8s.io/prometheus-adapter/pkg/client"
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"sigs.k8s.io/prometheus-adapter/pkg/naming"
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)
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// Runnable represents something that can be run until told to stop.
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type Runnable interface {
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// Run runs the runnable forever.
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Run()
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// RunUntil runs the runnable until the given channel is closed.
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RunUntil(stopChan <-chan struct{})
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}
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type prometheusProvider struct {
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mapper apimeta.RESTMapper
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kubeClient dynamic.Interface
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promClient prom.Client
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SeriesRegistry
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}
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func NewPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []naming.MetricNamer, updateInterval time.Duration, maxAge time.Duration) (provider.CustomMetricsProvider, Runnable) {
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lister := &cachingMetricsLister{
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updateInterval: updateInterval,
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maxAge: maxAge,
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promClient: promClient,
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namers: namers,
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SeriesRegistry: &basicSeriesRegistry{
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mapper: mapper,
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},
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}
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return &prometheusProvider{
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mapper: mapper,
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kubeClient: kubeClient,
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promClient: promClient,
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SeriesRegistry: lister,
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}, lister
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}
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func (p *prometheusProvider) metricFor(value pmodel.SampleValue, name types.NamespacedName, info provider.CustomMetricInfo, metricSelector labels.Selector) (*custom_metrics.MetricValue, error) {
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ref, err := helpers.ReferenceFor(p.mapper, name, info)
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if err != nil {
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return nil, err
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}
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var q *resource.Quantity
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if math.IsNaN(float64(value)) {
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q = resource.NewQuantity(0, resource.DecimalSI)
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} else {
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q = resource.NewMilliQuantity(int64(value*1000.0), resource.DecimalSI)
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}
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metric := &custom_metrics.MetricValue{
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DescribedObject: ref,
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Metric: custom_metrics.MetricIdentifier{
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Name: info.Metric,
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},
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// TODO(directxman12): use the right timestamp
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Timestamp: metav1.Time{Time: time.Now()},
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Value: *q,
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}
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if !metricSelector.Empty() {
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sel, err := metav1.ParseToLabelSelector(metricSelector.String())
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if err != nil {
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return nil, err
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}
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metric.Metric.Selector = sel
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}
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return metric, nil
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}
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func (p *prometheusProvider) metricsFor(valueSet pmodel.Vector, namespace string, names []string, info provider.CustomMetricInfo, metricSelector labels.Selector) (*custom_metrics.MetricValueList, error) {
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values, found := p.MatchValuesToNames(info, valueSet)
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if !found {
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return nil, provider.NewMetricNotFoundError(info.GroupResource, info.Metric)
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}
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res := []custom_metrics.MetricValue{}
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for _, name := range names {
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if _, found := values[name]; !found {
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continue
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}
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value, err := p.metricFor(values[name], types.NamespacedName{Namespace: namespace, Name: name}, info, metricSelector)
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if err != nil {
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return nil, err
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}
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res = append(res, *value)
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}
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return &custom_metrics.MetricValueList{
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Items: res,
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}, nil
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}
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func (p *prometheusProvider) buildQuery(ctx context.Context, info provider.CustomMetricInfo, namespace string, metricSelector labels.Selector, names ...string) (pmodel.Vector, error) {
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query, found := p.QueryForMetric(info, namespace, metricSelector, names...)
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if !found {
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return nil, provider.NewMetricNotFoundError(info.GroupResource, info.Metric)
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}
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// TODO: use an actual context
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queryResults, err := p.promClient.Query(ctx, pmodel.Now(), query)
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if err != nil {
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klog.Errorf("unable to fetch metrics from prometheus: %v", err)
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// don't leak implementation details to the user
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return nil, apierr.NewInternalError(fmt.Errorf("unable to fetch metrics"))
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}
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if queryResults.Type != pmodel.ValVector {
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klog.Errorf("unexpected results from prometheus: expected %s, got %s on results %v", pmodel.ValVector, queryResults.Type, queryResults)
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return nil, apierr.NewInternalError(fmt.Errorf("unable to fetch metrics"))
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}
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return *queryResults.Vector, nil
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}
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func (p *prometheusProvider) GetMetricByName(ctx context.Context, name types.NamespacedName, info provider.CustomMetricInfo, metricSelector labels.Selector) (*custom_metrics.MetricValue, error) {
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// construct a query
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queryResults, err := p.buildQuery(ctx, info, name.Namespace, metricSelector, name.Name)
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if err != nil {
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return nil, err
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}
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// associate the metrics
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if len(queryResults) < 1 {
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return nil, provider.NewMetricNotFoundForError(info.GroupResource, info.Metric, name.Name)
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}
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namedValues, found := p.MatchValuesToNames(info, queryResults)
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if !found {
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return nil, provider.NewMetricNotFoundError(info.GroupResource, info.Metric)
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}
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if len(namedValues) > 1 {
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klog.V(2).Infof("Got more than one result (%v results) when fetching metric %s for %q, using the first one with a matching name...", len(queryResults), info.String(), name)
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}
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resultValue, nameFound := namedValues[name.Name]
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if !nameFound {
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klog.Errorf("None of the results returned by when fetching metric %s for %q matched the resource name", info.String(), name)
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return nil, provider.NewMetricNotFoundForError(info.GroupResource, info.Metric, name.Name)
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}
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// return the resulting metric
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return p.metricFor(resultValue, name, info, metricSelector)
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}
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func (p *prometheusProvider) GetMetricBySelector(ctx context.Context, namespace string, selector labels.Selector, info provider.CustomMetricInfo, metricSelector labels.Selector) (*custom_metrics.MetricValueList, error) {
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// fetch a list of relevant resource names
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resourceNames, err := helpers.ListObjectNames(p.mapper, p.kubeClient, namespace, selector, info)
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if err != nil {
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klog.Errorf("unable to list matching resource names: %v", err)
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// don't leak implementation details to the user
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return nil, apierr.NewInternalError(fmt.Errorf("unable to list matching resources"))
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}
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// construct the actual query
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queryResults, err := p.buildQuery(ctx, info, namespace, metricSelector, resourceNames...)
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if err != nil {
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return nil, err
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}
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// return the resulting metrics
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return p.metricsFor(queryResults, namespace, resourceNames, info, metricSelector)
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}
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type cachingMetricsLister struct {
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SeriesRegistry
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promClient prom.Client
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updateInterval time.Duration
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maxAge time.Duration
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namers []naming.MetricNamer
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}
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func (l *cachingMetricsLister) Run() {
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l.RunUntil(wait.NeverStop)
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}
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func (l *cachingMetricsLister) RunUntil(stopChan <-chan struct{}) {
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go wait.Until(func() {
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if err := l.updateMetrics(); err != nil {
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utilruntime.HandleError(err)
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}
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}, l.updateInterval, stopChan)
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}
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type selectorSeries struct {
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selector prom.Selector
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series []prom.Series
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}
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func (l *cachingMetricsLister) updateMetrics() error {
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startTime := pmodel.Now().Add(-1 * l.maxAge)
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// don't do duplicate queries when it's just the matchers that change
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seriesCacheByQuery := make(map[prom.Selector][]prom.Series)
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// these can take a while on large clusters, so launch in parallel
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// and don't duplicate
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selectors := make(map[prom.Selector]struct{})
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selectorSeriesChan := make(chan selectorSeries, len(l.namers))
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errs := make(chan error, len(l.namers))
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for _, namer := range l.namers {
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sel := namer.Selector()
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if _, ok := selectors[sel]; ok {
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errs <- nil
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selectorSeriesChan <- selectorSeries{}
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continue
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}
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selectors[sel] = struct{}{}
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go func() {
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series, err := l.promClient.Series(context.TODO(), pmodel.Interval{Start: startTime, End: 0}, sel)
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if err != nil {
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errs <- fmt.Errorf("unable to fetch metrics for query %q: %v", sel, err)
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return
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}
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errs <- nil
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selectorSeriesChan <- selectorSeries{
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selector: sel,
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series: series,
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}
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}()
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}
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// iterate through, blocking until we've got all results
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for range l.namers {
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if err := <-errs; err != nil {
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return fmt.Errorf("unable to update list of all metrics: %v", err)
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}
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if ss := <-selectorSeriesChan; ss.series != nil {
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seriesCacheByQuery[ss.selector] = ss.series
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}
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}
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close(errs)
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newSeries := make([][]prom.Series, len(l.namers))
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for i, namer := range l.namers {
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series, cached := seriesCacheByQuery[namer.Selector()]
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if !cached {
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return fmt.Errorf("unable to update list of all metrics: no metrics retrieved for query %q", namer.Selector())
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}
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newSeries[i] = namer.FilterSeries(series)
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}
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klog.V(10).Infof("Set available metric list from Prometheus to: %v", newSeries)
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return l.SetSeries(newSeries, l.namers)
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}
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