Method remoteReadSamples

storage/remote/read_handler.go:116–186

(
	ctx context.Context,
	w http.ResponseWriter,
	req *prompb.ReadRequest,
	externalLabels map[string]string,
	sortedExternalLabels []prompb.Label,
)

}

func (h *readHandler) remoteReadSamples(
	ctx context.Context,
	w http.ResponseWriter,
	req *prompb.ReadRequest,
	externalLabels map[string]string,
	sortedExternalLabels []prompb.Label,
) {
	w.Header().Set("Content-Type", "application/x-protobuf")
	w.Header().Set("Content-Encoding", "snappy")

	resp := prompb.ReadResponse{
		Results: make([]*prompb.QueryResult, len(req.Queries)),
	}
	for i, query := range req.Queries {
		if err := func() error {
			filteredMatchers, err := filterExtLabelsFromMatchers(query.Matchers, externalLabels)
			if err != nil {
				return err
			}

			querier, err := h.queryable.Querier(query.StartTimestampMs, query.EndTimestampMs)
			if err != nil {
				return err
			}
			defer func() {
				if err := querier.Close(); err != nil {
					h.logger.Warn("Error on querier close", "err", err.Error())
				}
			}()

			var hints *storage.SelectHints
			if query.Hints != nil {
				hints = &storage.SelectHints{
					Start:    query.Hints.StartMs,
					End:      query.Hints.EndMs,
					Step:     query.Hints.StepMs,
					Func:     query.Hints.Func,
					Grouping: query.Hints.Grouping,
					Range:    query.Hints.RangeMs,
					By:       query.Hints.By,
				}
			}

			var ws annotations.Annotations
			resp.Results[i], ws, err = ToQueryResult(querier.Select(ctx, false, hints, filteredMatchers...), h.remoteReadSampleLimit)
			if err != nil {
				return err
			}
			for _, w := range ws {
				h.logger.Warn("Warnings on remote read query", "err", w.Error())
			}
			for _, ts := range resp.Results[i].Timeseries {
				ts.Labels = MergeLabels(ts.Labels, sortedExternalLabels)
			}
			return nil
		}(); err != nil {
			var httpErr HTTPError
			if errors.As(err, &httpErr) {