prometheus/storage/remote/read.go

262 lines
7.7 KiB
Go

// Copyright 2017 The Prometheus Authors
// 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 remote
import (
"context"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/storage"
)
var remoteReadQueries = prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "remote_read_queries",
Help: "The number of in-flight remote read queries.",
},
[]string{"client"},
)
func init() {
prometheus.MustRegister(remoteReadQueries)
}
// QueryableClient returns a storage.Queryable which queries the given
// Client to select series sets.
func QueryableClient(c *Client) storage.Queryable {
remoteReadQueries.WithLabelValues(c.Name())
return storage.QueryableFunc(func(ctx context.Context, mint, maxt int64) (storage.Querier, error) {
return &querier{
ctx: ctx,
mint: mint,
maxt: maxt,
client: c,
}, nil
})
}
// querier is an adapter to make a Client usable as a storage.Querier.
type querier struct {
ctx context.Context
mint, maxt int64
client *Client
}
// Select implements storage.Querier and uses the given matchers to read series
// sets from the Client.
func (q *querier) Select(p *storage.SelectParams, matchers ...*labels.Matcher) (storage.SeriesSet, storage.Warnings, error) {
query, err := ToQuery(q.mint, q.maxt, matchers, p)
if err != nil {
return nil, nil, err
}
remoteReadGauge := remoteReadQueries.WithLabelValues(q.client.Name())
remoteReadGauge.Inc()
defer remoteReadGauge.Dec()
res, err := q.client.Read(q.ctx, query)
if err != nil {
return nil, nil, err
}
return FromQueryResult(res), nil, nil
}
// LabelValues implements storage.Querier and is a noop.
func (q *querier) LabelValues(name string) ([]string, error) {
// TODO implement?
return nil, nil
}
// LabelNames implements storage.Querier and is a noop.
func (q *querier) LabelNames() ([]string, error) {
// TODO implement?
return nil, nil
}
// Close implements storage.Querier and is a noop.
func (q *querier) Close() error {
return nil
}
// ExternalLabelsHandler returns a storage.Queryable which creates a
// externalLabelsQuerier.
func ExternalLabelsHandler(next storage.Queryable, externalLabels model.LabelSet) storage.Queryable {
return storage.QueryableFunc(func(ctx context.Context, mint, maxt int64) (storage.Querier, error) {
q, err := next.Querier(ctx, mint, maxt)
if err != nil {
return nil, err
}
return &externalLabelsQuerier{Querier: q, externalLabels: externalLabels}, nil
})
}
// externalLabelsQuerier is a querier which ensures that Select() results match
// the configured external labels.
type externalLabelsQuerier struct {
storage.Querier
externalLabels model.LabelSet
}
// Select adds equality matchers for all external labels to the list of matchers
// before calling the wrapped storage.Queryable. The added external labels are
// removed from the returned series sets.
func (q externalLabelsQuerier) Select(p *storage.SelectParams, matchers ...*labels.Matcher) (storage.SeriesSet, storage.Warnings, error) {
m, added := q.addExternalLabels(matchers)
s, warnings, err := q.Querier.Select(p, m...)
if err != nil {
return nil, warnings, err
}
return newSeriesSetFilter(s, added), warnings, nil
}
// PreferLocalStorageFilter returns a QueryableFunc which creates a NoopQuerier
// if requested timeframe can be answered completely by the local TSDB, and
// reduces maxt if the timeframe can be partially answered by TSDB.
func PreferLocalStorageFilter(next storage.Queryable, cb startTimeCallback) storage.Queryable {
return storage.QueryableFunc(func(ctx context.Context, mint, maxt int64) (storage.Querier, error) {
localStartTime, err := cb()
if err != nil {
return nil, err
}
cmaxt := maxt
// Avoid queries whose timerange is later than the first timestamp in local DB.
if mint > localStartTime {
return storage.NoopQuerier(), nil
}
// Query only samples older than the first timestamp in local DB.
if maxt > localStartTime {
cmaxt = localStartTime
}
return next.Querier(ctx, mint, cmaxt)
})
}
// RequiredMatchersFilter returns a storage.Queryable which creates a
// requiredMatchersQuerier.
func RequiredMatchersFilter(next storage.Queryable, required []*labels.Matcher) storage.Queryable {
return storage.QueryableFunc(func(ctx context.Context, mint, maxt int64) (storage.Querier, error) {
q, err := next.Querier(ctx, mint, maxt)
if err != nil {
return nil, err
}
return &requiredMatchersQuerier{Querier: q, requiredMatchers: required}, nil
})
}
// requiredMatchersQuerier wraps a storage.Querier and requires Select() calls
// to match the given labelSet.
type requiredMatchersQuerier struct {
storage.Querier
requiredMatchers []*labels.Matcher
}
// Select returns a NoopSeriesSet if the given matchers don't match the label
// set of the requiredMatchersQuerier. Otherwise it'll call the wrapped querier.
func (q requiredMatchersQuerier) Select(p *storage.SelectParams, matchers ...*labels.Matcher) (storage.SeriesSet, storage.Warnings, error) {
ms := q.requiredMatchers
for _, m := range matchers {
for i, r := range ms {
if m.Type == labels.MatchEqual && m.Name == r.Name && m.Value == r.Value {
ms = append(ms[:i], ms[i+1:]...)
break
}
}
if len(ms) == 0 {
break
}
}
if len(ms) > 0 {
return storage.NoopSeriesSet(), nil, nil
}
return q.Querier.Select(p, matchers...)
}
// addExternalLabels adds matchers for each external label. External labels
// that already have a corresponding user-supplied matcher are skipped, as we
// assume that the user explicitly wants to select a different value for them.
// We return the new set of matchers, along with a map of labels for which
// matchers were added, so that these can later be removed from the result
// time series again.
func (q externalLabelsQuerier) addExternalLabels(ms []*labels.Matcher) ([]*labels.Matcher, model.LabelSet) {
el := make(model.LabelSet, len(q.externalLabels))
for k, v := range q.externalLabels {
el[k] = v
}
for _, m := range ms {
if _, ok := el[model.LabelName(m.Name)]; ok {
delete(el, model.LabelName(m.Name))
}
}
for k, v := range el {
m, err := labels.NewMatcher(labels.MatchEqual, string(k), string(v))
if err != nil {
panic(err)
}
ms = append(ms, m)
}
return ms, el
}
func newSeriesSetFilter(ss storage.SeriesSet, toFilter model.LabelSet) storage.SeriesSet {
return &seriesSetFilter{
SeriesSet: ss,
toFilter: toFilter,
}
}
type seriesSetFilter struct {
storage.SeriesSet
toFilter model.LabelSet
querier storage.Querier
}
func (ssf *seriesSetFilter) GetQuerier() storage.Querier {
return ssf.querier
}
func (ssf *seriesSetFilter) SetQuerier(querier storage.Querier) {
ssf.querier = querier
}
func (ssf seriesSetFilter) At() storage.Series {
return seriesFilter{
Series: ssf.SeriesSet.At(),
toFilter: ssf.toFilter,
}
}
type seriesFilter struct {
storage.Series
toFilter model.LabelSet
}
func (sf seriesFilter) Labels() labels.Labels {
labels := sf.Series.Labels()
for i := 0; i < len(labels); {
if _, ok := sf.toFilter[model.LabelName(labels[i].Name)]; ok {
labels = labels[:i+copy(labels[i:], labels[i+1:])]
continue
}
i++
}
return labels
}