mirror of
https://github.com/kubernetes-sigs/prometheus-adapter.git
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d02384477a
The latest boilerplate comes with a lot of simplifications and helpers that let us reduce the amount of code written.
113 lines
4.3 KiB
Go
113 lines
4.3 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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"fmt"
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apimeta "k8s.io/apimachinery/pkg/api/meta"
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"k8s.io/apimachinery/pkg/labels"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"k8s.io/apimachinery/pkg/types"
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"k8s.io/metrics/pkg/apis/custom_metrics"
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"k8s.io/metrics/pkg/apis/external_metrics"
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)
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// CustomMetricInfo describes a metric for a particular
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// fully-qualified group resource.
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type CustomMetricInfo struct {
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GroupResource schema.GroupResource
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Namespaced bool
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Metric string
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}
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// ExternalMetricInfo describes a metric.
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type ExternalMetricInfo struct {
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Metric string
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}
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func (i CustomMetricInfo) String() string {
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if i.Namespaced {
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return fmt.Sprintf("%s/%s(namespaced)", i.GroupResource.String(), i.Metric)
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} else {
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return fmt.Sprintf("%s/%s", i.GroupResource.String(), i.Metric)
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}
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}
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// Normalized returns a copy of the current MetricInfo with the GroupResource resolved using the
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// provided REST mapper, to ensure consistent pluralization, etc, for use when looking up or comparing
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// the MetricInfo. It also returns the singular form of the GroupResource associated with the given
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// MetricInfo.
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func (i CustomMetricInfo) Normalized(mapper apimeta.RESTMapper) (normalizedInfo CustomMetricInfo, singluarResource string, err error) {
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normalizedGroupRes, err := mapper.ResourceFor(i.GroupResource.WithVersion(""))
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if err != nil {
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return i, "", err
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}
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i.GroupResource = normalizedGroupRes.GroupResource()
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singularResource, err := mapper.ResourceSingularizer(i.GroupResource.Resource)
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if err != nil {
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return i, "", err
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}
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return i, singularResource, nil
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}
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// CustomMetricsProvider is a source of custom metrics
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// which is able to supply a list of available metrics,
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// as well as metric values themselves on demand.
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//
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// Note that group-resources are provided as GroupResources,
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// not GroupKinds. This is to allow flexibility on the part
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// of the implementor: implementors do not necessarily need
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// to be aware of all existing kinds and their corresponding
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// REST mappings in order to perform queries.
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//
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// For queries that use label selectors, it is up to the
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// implementor to decide how to make use of the label selector --
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// they may wish to query the main Kubernetes API server, or may
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// wish to simply make use of stored information in their TSDB.
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type CustomMetricsProvider interface {
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// GetMetricByName fetches a particular metric for a particular object.
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// The namespace will be empty if the metric is root-scoped.
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GetMetricByName(name types.NamespacedName, info CustomMetricInfo) (*custom_metrics.MetricValue, error)
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// GetMetricBySelector fetches a particular metric for a set of objects matching
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// the given label selector. The namespace will be empty if the metric is root-scoped.
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GetMetricBySelector(namespace string, selector labels.Selector, info CustomMetricInfo) (*custom_metrics.MetricValueList, error)
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// ListAllMetrics provides a list of all available metrics at
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// the current time. Note that this is not allowed to return
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// an error, so it is reccomended that implementors cache and
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// periodically update this list, instead of querying every time.
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ListAllMetrics() []CustomMetricInfo
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}
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// ExternalMetricsProvider is a source of external metrics.
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// Metric is normally idendified by a name and a set of labels/tags. It is up to a specific
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// implementation how to translate metricSelector to a filter for metric values.
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// Namespace can be used by the implemetation for metric identification, access control or ignored.
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type ExternalMetricsProvider interface {
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GetExternalMetric(namespace string, metricSelector labels.Selector, info ExternalMetricInfo) (*external_metrics.ExternalMetricValueList, error)
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ListAllExternalMetrics() []ExternalMetricInfo
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}
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type MetricsProvider interface {
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CustomMetricsProvider
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ExternalMetricsProvider
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}
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