99 lines
2.2 KiB
Go
99 lines
2.2 KiB
Go
package expressions
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import (
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"fmt"
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"github.com/prometheus/common/model"
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"github.com/prometheus/prometheus/promql"
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"github.com/prometheus/prometheus/storage/metric"
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)
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func init() {
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register("prometheus", labelReplace)
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}
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func labelReplace(input, ns string) (string, error) {
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root, err := promql.ParseExpr(input)
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if err != nil {
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return "", err
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}
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setRecursive(root, ns)
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if err != nil {
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return "", err
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}
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return root.String(), nil
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}
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// Inspired by https://github.com/prometheus-community/prom-label-proxy
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func setRecursive(node promql.Node, namespace string) (err error) {
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switch n := node.(type) {
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case *promql.EvalStmt:
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if err := setRecursive(n.Expr, namespace); err != nil {
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return err
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}
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case promql.Expressions:
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for _, e := range n {
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if err := setRecursive(e, namespace); err != nil {
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return err
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}
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}
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case *promql.AggregateExpr:
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if err := setRecursive(n.Expr, namespace); err != nil {
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return err
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}
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case *promql.BinaryExpr:
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if err := setRecursive(n.LHS, namespace); err != nil {
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return err
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}
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if err := setRecursive(n.RHS, namespace); err != nil {
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return err
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}
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case *promql.Call:
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if err := setRecursive(n.Args, namespace); err != nil {
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return err
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}
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case *promql.ParenExpr:
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if err := setRecursive(n.Expr, namespace); err != nil {
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return err
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}
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case *promql.UnaryExpr:
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if err := setRecursive(n.Expr, namespace); err != nil {
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return err
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}
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case *promql.NumberLiteral, *promql.StringLiteral:
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// nothing to do
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case *promql.MatrixSelector:
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n.LabelMatchers = enforceLabelMatchers(n.LabelMatchers, namespace)
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case *promql.VectorSelector:
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n.LabelMatchers = enforceLabelMatchers(n.LabelMatchers, namespace)
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default:
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return fmt.Errorf("promql.Walk: unhandled node type %T", node)
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}
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return err
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}
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func enforceLabelMatchers(matchers metric.LabelMatchers, namespace string) metric.LabelMatchers {
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var found bool
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for i, m := range matchers {
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if m.Name == "namespace" {
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matchers[i] = &metric.LabelMatcher{
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Name: "namespace",
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Type: metric.Equal,
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Value: model.LabelValue(namespace),
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}
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found = true
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break
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}
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}
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if !found {
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matchers = append(matchers, &metric.LabelMatcher{
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Name: "namespace",
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Type: metric.Equal,
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Value: model.LabelValue(namespace),
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})
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}
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return matchers
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}
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