114 lines
3.0 KiB
Go
114 lines
3.0 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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"github.com/prometheus/common/model"
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"golang.org/x/net/context"
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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 model.LabelSet
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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, labels model.LabelSet) *RecordingRule {
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return &RecordingRule{
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name: name,
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vector: vector,
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labels: labels,
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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(timestamp model.Time, engine *promql.Engine, queryCtx context.Context, _ string) (model.Vector, error) {
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query, err := engine.NewInstantQuery(rule.vector.String(), timestamp)
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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(queryCtx)
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vector model.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 result.Value.(type) {
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case model.Vector:
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vector, err = result.Vector()
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if err != nil {
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return nil, err
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}
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case *model.Scalar:
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scalar, err := result.Scalar()
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if err != nil {
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return nil, err
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}
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vector = model.Vector{&model.Sample{
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Value: scalar.Value,
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Timestamp: scalar.Timestamp,
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Metric: model.Metric{},
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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 _, sample := range vector {
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sample.Metric[model.MetricNameLabel] = model.LabelValue(rule.name)
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for label, value := range rule.labels {
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if value == "" {
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delete(sample.Metric, label)
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} else {
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sample.Metric[label] = value
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}
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}
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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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return fmt.Sprintf("%s%s = %s\n", rule.name, rule.labels, rule.vector)
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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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return template.HTML(fmt.Sprintf(
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`<a href="%s">%s</a>%s = <a href="%s">%s</a>`,
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pathPrefix+strutil.GraphLinkForExpression(rule.name),
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rule.name,
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template.HTMLEscapeString(rule.labels.String()),
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pathPrefix+strutil.GraphLinkForExpression(ruleExpr),
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template.HTMLEscapeString(ruleExpr)))
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}
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