281 lines
8.3 KiB
Go
281 lines
8.3 KiB
Go
// Copyright 2021 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 remote
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import (
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"context"
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"errors"
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"log/slog"
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"net/http"
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"slices"
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"strings"
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"sync"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/prometheus/config"
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"github.com/prometheus/prometheus/model/labels"
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"github.com/prometheus/prometheus/prompb"
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"github.com/prometheus/prometheus/storage"
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"github.com/prometheus/prometheus/util/annotations"
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"github.com/prometheus/prometheus/util/gate"
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)
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type readHandler struct {
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logger *slog.Logger
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queryable storage.SampleAndChunkQueryable
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config func() config.Config
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remoteReadSampleLimit int
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remoteReadMaxBytesInFrame int
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remoteReadGate *gate.Gate
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queries prometheus.Gauge
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marshalPool *sync.Pool
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}
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// NewReadHandler creates a http.Handler that accepts remote read requests and
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// writes them to the provided queryable.
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func NewReadHandler(logger *slog.Logger, r prometheus.Registerer, queryable storage.SampleAndChunkQueryable, config func() config.Config, remoteReadSampleLimit, remoteReadConcurrencyLimit, remoteReadMaxBytesInFrame int) http.Handler {
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h := &readHandler{
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logger: logger,
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queryable: queryable,
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config: config,
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remoteReadSampleLimit: remoteReadSampleLimit,
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remoteReadGate: gate.New(remoteReadConcurrencyLimit),
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remoteReadMaxBytesInFrame: remoteReadMaxBytesInFrame,
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marshalPool: &sync.Pool{},
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queries: prometheus.NewGauge(prometheus.GaugeOpts{
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Namespace: namespace,
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Subsystem: "remote_read_handler",
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Name: "queries",
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Help: "The current number of remote read queries that are either in execution or queued on the handler.",
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}),
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}
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if r != nil {
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r.MustRegister(h.queries)
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}
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return h
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}
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func (h *readHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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ctx := r.Context()
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if err := h.remoteReadGate.Start(ctx); err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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h.queries.Inc()
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defer h.remoteReadGate.Done()
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defer h.queries.Dec()
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req, err := DecodeReadRequest(r)
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if err != nil {
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http.Error(w, err.Error(), http.StatusBadRequest)
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return
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}
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externalLabels := h.config().GlobalConfig.ExternalLabels.Map()
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sortedExternalLabels := make([]prompb.Label, 0, len(externalLabels))
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for name, value := range externalLabels {
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sortedExternalLabels = append(sortedExternalLabels, prompb.Label{
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Name: name,
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Value: value,
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})
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}
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slices.SortFunc(sortedExternalLabels, func(a, b prompb.Label) int {
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return strings.Compare(a.Name, b.Name)
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})
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responseType, err := NegotiateResponseType(req.AcceptedResponseTypes)
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if err != nil {
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http.Error(w, err.Error(), http.StatusBadRequest)
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return
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}
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switch responseType {
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case prompb.ReadRequest_STREAMED_XOR_CHUNKS:
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h.remoteReadStreamedXORChunks(ctx, w, req, externalLabels, sortedExternalLabels)
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default:
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// On empty or unknown types in req.AcceptedResponseTypes we default to non streamed, raw samples response.
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h.remoteReadSamples(ctx, w, req, externalLabels, sortedExternalLabels)
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}
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}
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func (h *readHandler) remoteReadSamples(
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ctx context.Context,
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w http.ResponseWriter,
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req *prompb.ReadRequest,
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externalLabels map[string]string,
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sortedExternalLabels []prompb.Label,
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) {
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w.Header().Set("Content-Type", "application/x-protobuf")
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w.Header().Set("Content-Encoding", "snappy")
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resp := prompb.ReadResponse{
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Results: make([]*prompb.QueryResult, len(req.Queries)),
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}
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for i, query := range req.Queries {
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if err := func() error {
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filteredMatchers, err := filterExtLabelsFromMatchers(query.Matchers, externalLabels)
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if err != nil {
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return err
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}
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querier, err := h.queryable.Querier(query.StartTimestampMs, query.EndTimestampMs)
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if err != nil {
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return err
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}
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defer func() {
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if err := querier.Close(); err != nil {
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h.logger.Warn("Error on querier close", "err", err.Error())
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}
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}()
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var hints *storage.SelectHints
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if query.Hints != nil {
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hints = &storage.SelectHints{
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Start: query.Hints.StartMs,
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End: query.Hints.EndMs,
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Step: query.Hints.StepMs,
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Func: query.Hints.Func,
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Grouping: query.Hints.Grouping,
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Range: query.Hints.RangeMs,
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By: query.Hints.By,
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}
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}
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var ws annotations.Annotations
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resp.Results[i], ws, err = ToQueryResult(querier.Select(ctx, false, hints, filteredMatchers...), h.remoteReadSampleLimit)
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if err != nil {
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return err
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}
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for _, w := range ws {
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h.logger.Warn("Warnings on remote read query", "err", w.Error())
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}
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for _, ts := range resp.Results[i].Timeseries {
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ts.Labels = MergeLabels(ts.Labels, sortedExternalLabels)
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}
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return nil
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}(); err != nil {
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var httpErr HTTPError
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if errors.As(err, &httpErr) {
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http.Error(w, httpErr.Error(), httpErr.Status())
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return
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}
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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}
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if err := EncodeReadResponse(&resp, w); err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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}
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func (h *readHandler) remoteReadStreamedXORChunks(ctx context.Context, w http.ResponseWriter, req *prompb.ReadRequest, externalLabels map[string]string, sortedExternalLabels []prompb.Label) {
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w.Header().Set("Content-Type", "application/x-streamed-protobuf; proto=prometheus.ChunkedReadResponse")
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f, ok := w.(http.Flusher)
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if !ok {
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http.Error(w, "internal http.ResponseWriter does not implement http.Flusher interface", http.StatusInternalServerError)
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return
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}
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for i, query := range req.Queries {
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if err := func() error {
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filteredMatchers, err := filterExtLabelsFromMatchers(query.Matchers, externalLabels)
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if err != nil {
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return err
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}
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querier, err := h.queryable.ChunkQuerier(query.StartTimestampMs, query.EndTimestampMs)
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if err != nil {
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return err
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}
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defer func() {
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if err := querier.Close(); err != nil {
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h.logger.Warn("Error on chunk querier close", "err", err.Error())
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}
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}()
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var hints *storage.SelectHints
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if query.Hints != nil {
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hints = &storage.SelectHints{
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Start: query.Hints.StartMs,
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End: query.Hints.EndMs,
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Step: query.Hints.StepMs,
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Func: query.Hints.Func,
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Grouping: query.Hints.Grouping,
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Range: query.Hints.RangeMs,
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By: query.Hints.By,
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}
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}
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ws, err := StreamChunkedReadResponses(
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NewChunkedWriter(w, f),
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int64(i),
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// The streaming API has to provide the series sorted.
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querier.Select(ctx, true, hints, filteredMatchers...),
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sortedExternalLabels,
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h.remoteReadMaxBytesInFrame,
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h.marshalPool,
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)
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if err != nil {
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return err
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}
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for _, w := range ws {
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h.logger.Warn("Warnings on chunked remote read query", "warnings", w.Error())
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}
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return nil
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}(); err != nil {
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var httpErr HTTPError
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if errors.As(err, &httpErr) {
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http.Error(w, httpErr.Error(), httpErr.Status())
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return
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}
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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}
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}
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// filterExtLabelsFromMatchers change equality matchers which match external labels
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// to a matcher that looks for an empty label,
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// as that label should not be present in the storage.
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func filterExtLabelsFromMatchers(pbMatchers []*prompb.LabelMatcher, externalLabels map[string]string) ([]*labels.Matcher, error) {
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matchers, err := FromLabelMatchers(pbMatchers)
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if err != nil {
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return nil, err
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}
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filteredMatchers := make([]*labels.Matcher, 0, len(matchers))
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for _, m := range matchers {
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value := externalLabels[m.Name]
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if m.Type == labels.MatchEqual && value == m.Value {
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matcher, err := labels.NewMatcher(labels.MatchEqual, m.Name, "")
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if err != nil {
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return nil, err
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}
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filteredMatchers = append(filteredMatchers, matcher)
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} else {
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filteredMatchers = append(filteredMatchers, m)
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}
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}
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return filteredMatchers, nil
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}
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