mirror of
https://github.com/prometheus/prometheus
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c187308366
This is based on https://github.com/prometheus/prometheus/pull/1997. This adds contexts to the relevant Storage methods and already passes PromQL's new per-query context into the storage's query methods. The immediate motivation supporting multi-tenancy in Frankenstein, but this could also be used by Prometheus's normal local storage to support cancellations and timeouts at some point.
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(ctx context.Context, timestamp model.Time, engine *promql.Engine, _ 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(ctx)
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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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