prometheus/rules/recording.go

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// Copyright 2013 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package rules
import (
"context"
"fmt"
"html/template"
"net/url"
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"sync"
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"time"
yaml "gopkg.in/yaml.v2"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/pkg/rulefmt"
"github.com/prometheus/prometheus/promql"
"github.com/prometheus/prometheus/promql/parser"
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"github.com/prometheus/prometheus/util/strutil"
)
// A RecordingRule records its vector expression into new timeseries.
type RecordingRule struct {
name string
vector parser.Expr
labels labels.Labels
// Protects the below.
mtx sync.Mutex
// The health of the recording rule.
health RuleHealth
// Timestamp of last evaluation of the recording rule.
evaluationTimestamp time.Time
// The last error seen by the recording rule.
lastError error
// Duration of how long it took to evaluate the recording rule.
evaluationDuration time.Duration
}
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// NewRecordingRule returns a new recording rule.
func NewRecordingRule(name string, vector parser.Expr, lset labels.Labels) *RecordingRule {
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return &RecordingRule{
name: name,
vector: vector,
health: HealthUnknown,
labels: lset,
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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
}
// Query returns the rule query expression.
func (rule *RecordingRule) Query() parser.Expr {
return rule.vector
}
// Labels returns the rule labels.
func (rule *RecordingRule) Labels() labels.Labels {
return rule.labels
}
// Eval evaluates the rule and then overrides the metric names and labels accordingly.
func (rule *RecordingRule) Eval(ctx context.Context, ts time.Time, query QueryFunc, _ *url.URL) (promql.Vector, error) {
vector, err := query(ctx, rule.vector.String(), ts)
if err != nil {
rule.SetHealth(HealthBad)
rule.SetLastError(err)
return nil, err
}
// Override the metric name and labels.
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for i := range vector {
sample := &vector[i]
lb := labels.NewBuilder(sample.Metric)
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lb.Set(labels.MetricName, rule.name)
for _, l := range rule.labels {
lb.Set(l.Name, l.Value)
}
sample.Metric = lb.Labels()
}
// Check that the rule does not produce identical metrics after applying
// labels.
if vector.ContainsSameLabelset() {
err = fmt.Errorf("vector contains metrics with the same labelset after applying rule labels")
rule.SetHealth(HealthBad)
rule.SetLastError(err)
return nil, err
}
rule.SetHealth(HealthGood)
rule.SetLastError(err)
return vector, nil
}
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func (rule *RecordingRule) String() string {
r := rulefmt.Rule{
Record: rule.name,
Expr: rule.vector.String(),
Labels: rule.labels.Map(),
}
byt, err := yaml.Marshal(r)
if err != nil {
return fmt.Sprintf("error marshaling recording rule: %q", err.Error())
}
return string(byt)
}
// SetEvaluationDuration updates evaluationDuration to the time in seconds it took to evaluate the rule on its last evaluation.
func (rule *RecordingRule) SetEvaluationDuration(dur time.Duration) {
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rule.mtx.Lock()
defer rule.mtx.Unlock()
rule.evaluationDuration = dur
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}
// SetLastError sets the current error seen by the recording rule.
func (rule *RecordingRule) SetLastError(err error) {
rule.mtx.Lock()
defer rule.mtx.Unlock()
rule.lastError = err
}
// LastError returns the last error seen by the recording rule.
func (rule *RecordingRule) LastError() error {
rule.mtx.Lock()
defer rule.mtx.Unlock()
return rule.lastError
}
// SetHealth sets the current health of the recording rule.
func (rule *RecordingRule) SetHealth(health RuleHealth) {
rule.mtx.Lock()
defer rule.mtx.Unlock()
rule.health = health
}
// Health returns the current health of the recording rule.
func (rule *RecordingRule) Health() RuleHealth {
rule.mtx.Lock()
defer rule.mtx.Unlock()
return rule.health
}
// GetEvaluationDuration returns the time in seconds it took to evaluate the recording rule.
func (rule *RecordingRule) GetEvaluationDuration() time.Duration {
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rule.mtx.Lock()
defer rule.mtx.Unlock()
return rule.evaluationDuration
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}
// SetEvaluationTimestamp updates evaluationTimestamp to the timestamp of when the rule was last evaluated.
func (rule *RecordingRule) SetEvaluationTimestamp(ts time.Time) {
rule.mtx.Lock()
defer rule.mtx.Unlock()
rule.evaluationTimestamp = ts
}
// GetEvaluationTimestamp returns the time the evaluation took place.
func (rule *RecordingRule) GetEvaluationTimestamp() time.Time {
rule.mtx.Lock()
defer rule.mtx.Unlock()
return rule.evaluationTimestamp
}
// HTMLSnippet returns an HTML snippet representing this rule.
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func (rule *RecordingRule) HTMLSnippet(pathPrefix string) template.HTML {
ruleExpr := rule.vector.String()
labels := make(map[string]string, len(rule.labels))
for _, l := range rule.labels {
labels[l.Name] = template.HTMLEscapeString(l.Value)
}
r := rulefmt.Rule{
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Record: fmt.Sprintf(`<a href="%s">%s</a>`, pathPrefix+strutil.TableLinkForExpression(rule.name), rule.name),
Expr: fmt.Sprintf(`<a href="%s">%s</a>`, pathPrefix+strutil.TableLinkForExpression(ruleExpr), template.HTMLEscapeString(ruleExpr)),
Labels: labels,
}
byt, err := yaml.Marshal(r)
if err != nil {
return template.HTML(fmt.Sprintf("error marshaling recording rule: %q", template.HTMLEscapeString(err.Error())))
}
return template.HTML(byt)
}