prometheus/rules/recording.go

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// Copyright 2013 Prometheus Team
// 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 (
"fmt"
"html/template"
clientmodel "github.com/prometheus/client_golang/model"
"github.com/prometheus/prometheus/rules/ast"
"github.com/prometheus/prometheus/stats"
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"github.com/prometheus/prometheus/storage/metric"
)
// A RecordingRule records its vector expression into new timeseries.
type RecordingRule struct {
name string
vector ast.VectorNode
labels clientmodel.LabelSet
permanent bool
}
func (rule RecordingRule) Name() string { return rule.name }
func (rule RecordingRule) EvalRaw(timestamp clientmodel.Timestamp, storage metric.PreloadingPersistence) (ast.Vector, error) {
return ast.EvalVectorInstant(rule.vector, timestamp, storage, stats.NewTimerGroup())
}
func (rule RecordingRule) Eval(timestamp clientmodel.Timestamp, storage metric.PreloadingPersistence) (ast.Vector, error) {
// Get the raw value of the rule expression.
vector, err := rule.EvalRaw(timestamp, storage)
if err != nil {
return nil, err
}
// Override the metric name and labels.
for _, sample := range vector {
sample.Metric[clientmodel.MetricNameLabel] = clientmodel.LabelValue(rule.name)
for label, value := range rule.labels {
if value == "" {
delete(sample.Metric, label)
} else {
sample.Metric[label] = value
}
}
}
return vector, nil
}
func (rule RecordingRule) ToDotGraph() string {
graph := fmt.Sprintf(`digraph "Rules" {
%#p[shape="box",label="%s = "];
%#p -> %#p;
%s
}`, &rule, rule.name, &rule, rule.vector, rule.vector.NodeTreeToDotGraph())
return graph
}
func (rule RecordingRule) String() string {
return fmt.Sprintf("%s%s = %s\n", rule.name, rule.labels, rule.vector)
}
func (rule RecordingRule) HTMLSnippet() template.HTML {
ruleExpr := rule.vector.String()
return template.HTML(fmt.Sprintf(
`<a href="%s">%s</a>%s = <a href="%s">%s</a>`,
GraphLinkForExpression(rule.name),
rule.name,
rule.labels,
GraphLinkForExpression(ruleExpr),
ruleExpr))
}
// Construct a new RecordingRule.
func NewRecordingRule(name string, labels clientmodel.LabelSet, vector ast.VectorNode, permanent bool) *RecordingRule {
return &RecordingRule{
name: name,
labels: labels,
vector: vector,
permanent: permanent,
}
}