mirror of
https://github.com/kubernetes-sigs/prometheus-adapter.git
synced 2026-04-06 01:38:10 +00:00
a94494337e
* Wiped out a ton of warnings about comments. * Created consts for `MetricType` values. * `externalInfoMap` can now track multiple series with the same name/namespace and different labels. * `namespace` parameter of external metrics queries is now respected (albeit very rudimentarily) * Metric converter values for external metrics are now converted the same way as for custom metrics (probably still some opportunity for consolidation). * Lots of TODOs actually done. * Deleted a lot of commented out code.
98 lines
2.8 KiB
Go
98 lines
2.8 KiB
Go
package provider
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import (
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"bytes"
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"fmt"
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"strings"
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"text/template"
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prom "github.com/directxman12/k8s-prometheus-adapter/pkg/client"
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)
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//QueryBuilder provides functions for generating Prometheus queries.
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type QueryBuilder interface {
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BuildSelector(seriesName string, groupBy string, groupBySlice []string, queryParts []queryPart) (prom.Selector, error)
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}
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type queryBuilder struct {
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metricsQueryTemplate *template.Template
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}
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//NewQueryBuilder creates a QueryBuilder.
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func NewQueryBuilder(metricsQuery string) (QueryBuilder, error) {
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metricsQueryTemplate, err := template.New("metrics-query").Delims("<<", ">>").Parse(metricsQuery)
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if err != nil {
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return nil, fmt.Errorf("unable to parse metrics query template %q: %v", metricsQuery, err)
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}
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return &queryBuilder{
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metricsQueryTemplate: metricsQueryTemplate,
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}, nil
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}
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func (n *queryBuilder) BuildSelector(seriesName string, groupBy string, groupBySlice []string, queryParts []queryPart) (prom.Selector, error) {
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//Convert our query parts into the types we need for our template.
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exprs, valuesByName := n.processQueryParts(queryParts)
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args := queryTemplateArgs{
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Series: seriesName,
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LabelMatchers: strings.Join(exprs, ","),
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LabelValuesByName: valuesByName,
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GroupBy: groupBy,
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GroupBySlice: groupBySlice,
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}
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selector, err := n.createSelectorFromTemplateArgs(args)
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if err != nil {
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return "", err
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}
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return selector, nil
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}
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func (n *queryBuilder) createSelectorFromTemplateArgs(args queryTemplateArgs) (prom.Selector, error) {
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//Turn our template arguments into a Selector.
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queryBuff := new(bytes.Buffer)
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if err := n.metricsQueryTemplate.Execute(queryBuff, args); err != nil {
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return "", err
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}
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if queryBuff.Len() == 0 {
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return "", fmt.Errorf("empty query produced by metrics query template")
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}
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return prom.Selector(queryBuff.String()), nil
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}
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func (n *queryBuilder) processQueryParts(queryParts []queryPart) ([]string, map[string][]string) {
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//Contains the expressions that we want to include as part of the query to Prometheus.
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//e.g. "namespace=my-namespace"
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//e.g. "some_label=some-value"
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var exprs []string
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//Contains the list of label values we're targeting, by namespace.
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//e.g. "some_label" => ["value-one", "value-two"]
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valuesByName := map[string][]string{}
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//Convert our query parts into template arguments.
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for _, qPart := range queryParts {
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//Be resilient against bad inputs.
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//We obviously can't generate label filters for these cases.
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if qPart.labelName == "" || len(qPart.values) == 0 {
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continue
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}
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targetValue := qPart.values[0]
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matcher := prom.LabelEq
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if len(qPart.values) > 1 {
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targetValue = strings.Join(qPart.values, "|")
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matcher = prom.LabelMatches
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}
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expression := matcher(qPart.labelName, targetValue)
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exprs = append(exprs, expression)
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valuesByName[qPart.labelName] = qPart.values
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}
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return exprs, valuesByName
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}
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