138 lines
3.7 KiB
Go
138 lines
3.7 KiB
Go
// Copyright 2013 Prometheus Team
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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 ast
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import (
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"flag"
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"github.com/prometheus/prometheus/model"
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"github.com/prometheus/prometheus/storage/metric"
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"time"
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)
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var defaultStalenessDelta = flag.Int("defaultStalenessDelta", 300, "Default staleness delta allowance in seconds during expression evaluations.")
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// AST-global storage to use for operations that are not supported by views
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// (i.e. metric->fingerprint lookups).
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var queryStorage metric.Storage = nil
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type viewAdapter struct {
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view metric.View
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// TODO: use this.
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stalenessPolicy *metric.StalenessPolicy
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}
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func (v *viewAdapter) chooseClosestSample(samples []model.SamplePair, timestamp *time.Time) (sample *model.SamplePair) {
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var minDelta time.Duration
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for _, candidate := range samples {
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// Ignore samples outside of staleness policy window.
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delta := candidate.Timestamp.Sub(*timestamp)
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if delta < 0 {
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delta = -delta
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}
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if delta > v.stalenessPolicy.DeltaAllowance {
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continue
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}
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// Skip sample if we've seen a closer one before this.
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if sample != nil {
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if delta > minDelta {
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continue
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}
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}
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sample = &candidate
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minDelta = delta
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}
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return
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}
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func (v *viewAdapter) GetValueAtTime(fingerprints model.Fingerprints, timestamp *time.Time) (samples []*model.Sample, err error) {
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for _, fingerprint := range fingerprints {
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sampleCandidates := v.view.GetValueAtTime(fingerprint, *timestamp)
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samplePair := v.chooseClosestSample(sampleCandidates, timestamp)
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m, err := queryStorage.GetMetricForFingerprint(fingerprint)
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if err != nil {
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continue
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}
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if samplePair != nil {
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samples = append(samples, &model.Sample{
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Metric: *m,
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Value: samplePair.Value,
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Timestamp: *timestamp,
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})
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}
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}
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return
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}
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func (v *viewAdapter) GetBoundaryValues(fingerprints model.Fingerprints, interval *model.Interval) (sampleSets []*model.SampleSet, err error) {
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for _, fingerprint := range fingerprints {
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// TODO: change to GetBoundaryValues() once it has the right return type.
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samplePairs := v.view.GetRangeValues(fingerprint, *interval)
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if samplePairs == nil {
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continue
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}
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// TODO: memoize/cache this.
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m, err := queryStorage.GetMetricForFingerprint(fingerprint)
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if err != nil {
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continue
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}
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sampleSet := &model.SampleSet{
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Metric: *m,
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Values: samplePairs,
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}
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sampleSets = append(sampleSets, sampleSet)
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}
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return sampleSets, nil
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}
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func (v *viewAdapter) GetRangeValues(fingerprints model.Fingerprints, interval *model.Interval) (sampleSets []*model.SampleSet, err error) {
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for _, fingerprint := range fingerprints {
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samplePairs := v.view.GetRangeValues(fingerprint, *interval)
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if samplePairs == nil {
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continue
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}
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// TODO: memoize/cache this.
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m, err := queryStorage.GetMetricForFingerprint(fingerprint)
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if err != nil {
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continue
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}
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sampleSet := &model.SampleSet{
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Metric: *m,
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Values: samplePairs,
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}
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sampleSets = append(sampleSets, sampleSet)
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}
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return sampleSets, nil
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}
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func SetStorage(storage metric.Storage) {
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queryStorage = storage
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}
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func NewViewAdapter(view metric.View) *viewAdapter {
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stalenessPolicy := metric.StalenessPolicy{
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DeltaAllowance: time.Duration(*defaultStalenessDelta) * time.Second,
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}
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return &viewAdapter{
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view: view,
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stalenessPolicy: &stalenessPolicy,
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}
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}
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