138 lines
3.4 KiB
Go
138 lines
3.4 KiB
Go
// Copyright 2013 The Prometheus 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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package rules
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import (
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"fmt"
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"html/template"
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"net/url"
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"time"
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yaml "gopkg.in/yaml.v2"
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"golang.org/x/net/context"
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"github.com/prometheus/prometheus/pkg/labels"
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"github.com/prometheus/prometheus/pkg/rulefmt"
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"github.com/prometheus/prometheus/promql"
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"github.com/prometheus/prometheus/util/strutil"
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)
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// A RecordingRule records its vector expression into new timeseries.
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type RecordingRule struct {
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name string
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vector promql.Expr
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labels labels.Labels
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}
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// NewRecordingRule returns a new recording rule.
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func NewRecordingRule(name string, vector promql.Expr, lset labels.Labels) *RecordingRule {
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return &RecordingRule{
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name: name,
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vector: vector,
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labels: lset,
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}
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}
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// Name returns the rule name.
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func (rule RecordingRule) Name() string {
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return rule.name
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}
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// Eval evaluates the rule and then overrides the metric names and labels accordingly.
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func (rule RecordingRule) Eval(ctx context.Context, ts time.Time, engine *promql.Engine, _ *url.URL) (promql.Vector, error) {
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query, err := engine.NewInstantQuery(rule.vector.String(), ts)
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if err != nil {
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return nil, err
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}
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var (
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result = query.Exec(ctx)
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vector promql.Vector
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)
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if result.Err != nil {
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return nil, err
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}
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switch v := result.Value.(type) {
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case promql.Vector:
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vector = v
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case promql.Scalar:
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vector = promql.Vector{promql.Sample{
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Point: promql.Point(v),
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Metric: labels.Labels{},
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}}
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default:
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return nil, fmt.Errorf("rule result is not a vector or scalar")
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}
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// Override the metric name and labels.
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for i := range vector {
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sample := &vector[i]
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lb := labels.NewBuilder(sample.Metric)
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lb.Set(labels.MetricName, rule.name)
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for _, l := range rule.labels {
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if l.Value == "" {
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lb.Del(l.Name)
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} else {
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lb.Set(l.Name, l.Value)
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}
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}
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sample.Metric = lb.Labels()
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}
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return vector, nil
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}
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func (rule RecordingRule) String() string {
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r := rulefmt.Rule{
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Record: rule.name,
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Expr: rule.vector.String(),
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Labels: rule.labels.Map(),
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}
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byt, err := yaml.Marshal(r)
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if err != nil {
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return fmt.Sprintf("error marshalling recording rule: %q", err.Error())
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}
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return string(byt)
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}
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// HTMLSnippet returns an HTML snippet representing this rule.
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func (rule RecordingRule) HTMLSnippet(pathPrefix string) template.HTML {
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ruleExpr := rule.vector.String()
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labels := make(map[string]string, len(rule.labels))
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for _, l := range rule.labels {
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labels[l.Name] = template.HTMLEscapeString(l.Value)
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}
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r := rulefmt.Rule{
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Record: fmt.Sprintf(`<a href="%s">%s</a>`, pathPrefix+strutil.GraphLinkForExpression(rule.name), rule.name),
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Expr: fmt.Sprintf(`<a href="%s">%s</a>`, pathPrefix+strutil.GraphLinkForExpression(ruleExpr), template.HTMLEscapeString(ruleExpr)),
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Labels: labels,
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}
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byt, err := yaml.Marshal(r)
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if err != nil {
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return template.HTML(fmt.Sprintf("error marshalling recording rule: %q", err.Error()))
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}
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return template.HTML(byt)
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}
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