prometheus/rules/ast/query_analyzer.go
2013-05-07 13:15:10 +02:00

134 lines
4.6 KiB
Go

// 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 ast
import (
"github.com/prometheus/prometheus/model"
"github.com/prometheus/prometheus/storage/metric"
"log"
"time"
)
type FullRangeMap map[model.Fingerprint]time.Duration
type IntervalRangeMap map[model.Fingerprint]bool
type QueryAnalyzer struct {
// Values collected by query analysis.
//
// Full ranges always implicitly span a time range of:
// - start: query interval start - duration
// - end: query interval end
//
// This is because full ranges can only result from matrix literals (like
// "foo[5m]"), which have said time-spanning behavior during a ranged query.
FullRanges FullRangeMap
// Interval ranges always implicitly span the whole query interval.
IntervalRanges IntervalRangeMap
// The underlying storage to which the query will be applied. Needed for
// extracting timeseries fingerprint information during query analysis.
storage *metric.TieredStorage
}
func NewQueryAnalyzer(storage *metric.TieredStorage) *QueryAnalyzer {
return &QueryAnalyzer{
FullRanges: FullRangeMap{},
IntervalRanges: IntervalRangeMap{},
storage: storage,
}
}
func (analyzer *QueryAnalyzer) Visit(node Node) {
switch n := node.(type) {
case *VectorLiteral:
fingerprints, err := analyzer.storage.GetFingerprintsForLabelSet(n.labels)
if err != nil {
log.Printf("Error getting fingerprints for labelset %v: %v", n.labels, err)
return
}
n.fingerprints = fingerprints
for _, fingerprint := range fingerprints {
if !analyzer.IntervalRanges[fingerprint] {
analyzer.IntervalRanges[fingerprint] = true
}
}
case *MatrixLiteral:
fingerprints, err := analyzer.storage.GetFingerprintsForLabelSet(n.labels)
if err != nil {
log.Printf("Error getting fingerprints for labelset %v: %v", n.labels, err)
return
}
n.fingerprints = fingerprints
for _, fingerprint := range fingerprints {
interval := n.interval
// If an interval has already been recorded for this fingerprint, merge
// it with the current interval.
if oldInterval, ok := analyzer.FullRanges[fingerprint]; ok {
if oldInterval > interval {
interval = oldInterval
}
}
analyzer.FullRanges[fingerprint] = interval
}
}
}
func (analyzer *QueryAnalyzer) AnalyzeQueries(node Node) {
Walk(analyzer, node)
// Find and dedupe overlaps between full and stepped ranges. Full ranges
// always contain more points *and* span more time than stepped ranges, so
// throw away stepped ranges for fingerprints which have full ranges.
for fingerprint := range analyzer.FullRanges {
if analyzer.IntervalRanges[fingerprint] {
delete(analyzer.IntervalRanges, fingerprint)
}
}
}
func viewAdapterForInstantQuery(node Node, timestamp time.Time, storage *metric.TieredStorage) (viewAdapter *viewAdapter, err error) {
analyzer := NewQueryAnalyzer(storage)
analyzer.AnalyzeQueries(node)
viewBuilder := metric.NewViewRequestBuilder()
for fingerprint, rangeDuration := range analyzer.FullRanges {
viewBuilder.GetMetricRange(fingerprint, timestamp.Add(-rangeDuration), timestamp)
}
for fingerprint := range analyzer.IntervalRanges {
viewBuilder.GetMetricAtTime(fingerprint, timestamp)
}
view, err := analyzer.storage.MakeView(viewBuilder, time.Duration(60)*time.Second)
if err == nil {
viewAdapter = NewViewAdapter(view, storage)
}
return
}
func viewAdapterForRangeQuery(node Node, start time.Time, end time.Time, interval time.Duration, storage *metric.TieredStorage) (viewAdapter *viewAdapter, err error) {
analyzer := NewQueryAnalyzer(storage)
analyzer.AnalyzeQueries(node)
viewBuilder := metric.NewViewRequestBuilder()
for fingerprint, rangeDuration := range analyzer.FullRanges {
// TODO: we should support GetMetricRangeAtInterval() or similar ops in the view builder.
for t := start; t.Before(end); t = t.Add(interval) {
viewBuilder.GetMetricRange(fingerprint, t.Add(-rangeDuration), t)
}
}
for fingerprint := range analyzer.IntervalRanges {
viewBuilder.GetMetricAtInterval(fingerprint, start, end, interval)
}
view, err := analyzer.storage.MakeView(viewBuilder, time.Duration(60)*time.Second)
if err == nil {
viewAdapter = NewViewAdapter(view, storage)
}
return
}