mirror of
https://github.com/prometheus/prometheus.git
synced 2024-12-26 14:09:41 -08:00
293 lines
8.5 KiB
Go
293 lines
8.5 KiB
Go
// Copyright 2016 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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"bufio"
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"bytes"
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"context"
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"fmt"
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"io"
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"io/ioutil"
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"net/http"
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"strconv"
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"strings"
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"time"
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"github.com/gogo/protobuf/proto"
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"github.com/golang/snappy"
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"github.com/opentracing/opentracing-go"
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"github.com/pkg/errors"
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"github.com/prometheus/client_golang/prometheus"
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config_util "github.com/prometheus/common/config"
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"github.com/prometheus/common/model"
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"github.com/prometheus/common/version"
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"github.com/opentracing-contrib/go-stdlib/nethttp"
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"github.com/prometheus/prometheus/prompb"
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)
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const maxErrMsgLen = 256
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var UserAgent = fmt.Sprintf("Prometheus/%s", version.Version)
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var (
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remoteReadQueriesTotal = prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Namespace: namespace,
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Subsystem: subsystem,
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Name: "read_queries_total",
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Help: "The total number of remote read queries.",
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},
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[]string{remoteName, endpoint, "code"},
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)
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remoteReadQueries = prometheus.NewGaugeVec(
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prometheus.GaugeOpts{
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Namespace: namespace,
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Subsystem: subsystem,
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Name: "remote_read_queries",
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Help: "The number of in-flight remote read queries.",
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},
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[]string{remoteName, endpoint},
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)
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remoteReadQueryDuration = prometheus.NewHistogramVec(
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prometheus.HistogramOpts{
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Namespace: namespace,
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Subsystem: subsystem,
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Name: "read_request_duration_seconds",
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Help: "Histogram of the latency for remote read requests.",
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Buckets: append(prometheus.DefBuckets, 25, 60),
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},
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[]string{remoteName, endpoint},
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)
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)
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func init() {
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prometheus.MustRegister(remoteReadQueriesTotal, remoteReadQueries, remoteReadQueryDuration)
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}
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// Client allows reading and writing from/to a remote HTTP endpoint.
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type Client struct {
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remoteName string // Used to differentiate clients in metrics.
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url *config_util.URL
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Client *http.Client
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timeout time.Duration
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readQueries prometheus.Gauge
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readQueriesTotal *prometheus.CounterVec
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readQueriesDuration prometheus.Observer
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}
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// ClientConfig configures a client.
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type ClientConfig struct {
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URL *config_util.URL
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Timeout model.Duration
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HTTPClientConfig config_util.HTTPClientConfig
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}
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// ReadClient uses the SAMPLES method of remote read to read series samples from remote server.
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// TODO(bwplotka): Add streamed chunked remote read method as well (https://github.com/prometheus/prometheus/issues/5926).
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type ReadClient interface {
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Read(ctx context.Context, query *prompb.Query) (*prompb.QueryResult, error)
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}
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// newReadClient creates a new client for remote read.
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func newReadClient(name string, conf *ClientConfig) (ReadClient, error) {
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httpClient, err := config_util.NewClientFromConfig(conf.HTTPClientConfig, "remote_storage_read_client", false, false)
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if err != nil {
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return nil, err
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}
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return &Client{
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remoteName: name,
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url: conf.URL,
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Client: httpClient,
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timeout: time.Duration(conf.Timeout),
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readQueries: remoteReadQueries.WithLabelValues(name, conf.URL.String()),
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readQueriesTotal: remoteReadQueriesTotal.MustCurryWith(prometheus.Labels{remoteName: name, endpoint: conf.URL.String()}),
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readQueriesDuration: remoteReadQueryDuration.WithLabelValues(name, conf.URL.String()),
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}, nil
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}
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// NewWriteClient creates a new client for remote write.
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func NewWriteClient(name string, conf *ClientConfig) (WriteClient, error) {
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httpClient, err := config_util.NewClientFromConfig(conf.HTTPClientConfig, "remote_storage_write_client", false, false)
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if err != nil {
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return nil, err
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}
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t := httpClient.Transport
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httpClient.Transport = &nethttp.Transport{
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RoundTripper: t,
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}
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return &Client{
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remoteName: name,
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url: conf.URL,
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Client: httpClient,
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timeout: time.Duration(conf.Timeout),
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}, nil
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}
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type RecoverableError struct {
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error
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}
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// Store sends a batch of samples to the HTTP endpoint, the request is the proto marshalled
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// and encoded bytes from codec.go.
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func (c *Client) Store(ctx context.Context, req []byte) error {
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httpReq, err := http.NewRequest("POST", c.url.String(), bytes.NewReader(req))
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if err != nil {
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// Errors from NewRequest are from unparsable URLs, so are not
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// recoverable.
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return err
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}
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httpReq.Header.Add("Content-Encoding", "snappy")
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httpReq.Header.Set("Content-Type", "application/x-protobuf")
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httpReq.Header.Set("User-Agent", UserAgent)
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httpReq.Header.Set("X-Prometheus-Remote-Write-Version", "0.1.0")
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ctx, cancel := context.WithTimeout(ctx, c.timeout)
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defer cancel()
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httpReq = httpReq.WithContext(ctx)
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if parentSpan := opentracing.SpanFromContext(ctx); parentSpan != nil {
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var ht *nethttp.Tracer
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httpReq, ht = nethttp.TraceRequest(
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parentSpan.Tracer(),
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httpReq,
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nethttp.OperationName("Remote Store"),
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nethttp.ClientTrace(false),
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)
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defer ht.Finish()
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}
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httpResp, err := c.Client.Do(httpReq)
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if err != nil {
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// Errors from Client.Do are from (for example) network errors, so are
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// recoverable.
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return RecoverableError{err}
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}
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defer func() {
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io.Copy(ioutil.Discard, httpResp.Body)
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httpResp.Body.Close()
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}()
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if httpResp.StatusCode/100 != 2 {
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scanner := bufio.NewScanner(io.LimitReader(httpResp.Body, maxErrMsgLen))
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line := ""
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if scanner.Scan() {
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line = scanner.Text()
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}
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err = errors.Errorf("server returned HTTP status %s: %s", httpResp.Status, line)
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}
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if httpResp.StatusCode/100 == 5 {
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return RecoverableError{err}
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}
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return err
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}
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// Name uniquely identifies the client.
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func (c Client) Name() string {
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return c.remoteName
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}
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// Endpoint is the remote read or write endpoint.
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func (c Client) Endpoint() string {
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return c.url.String()
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}
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// Read reads from a remote endpoint.
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func (c *Client) Read(ctx context.Context, query *prompb.Query) (*prompb.QueryResult, error) {
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c.readQueries.Inc()
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defer c.readQueries.Dec()
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req := &prompb.ReadRequest{
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// TODO: Support batching multiple queries into one read request,
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// as the protobuf interface allows for it.
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Queries: []*prompb.Query{
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query,
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},
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}
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data, err := proto.Marshal(req)
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if err != nil {
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return nil, errors.Wrapf(err, "unable to marshal read request")
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}
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compressed := snappy.Encode(nil, data)
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httpReq, err := http.NewRequest("POST", c.url.String(), bytes.NewReader(compressed))
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if err != nil {
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return nil, errors.Wrap(err, "unable to create request")
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}
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httpReq.Header.Add("Content-Encoding", "snappy")
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httpReq.Header.Add("Accept-Encoding", "snappy")
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httpReq.Header.Set("Content-Type", "application/x-protobuf")
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httpReq.Header.Set("User-Agent", UserAgent)
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httpReq.Header.Set("X-Prometheus-Remote-Read-Version", "0.1.0")
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ctx, cancel := context.WithTimeout(ctx, c.timeout)
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defer cancel()
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httpReq = httpReq.WithContext(ctx)
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if parentSpan := opentracing.SpanFromContext(ctx); parentSpan != nil {
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var ht *nethttp.Tracer
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httpReq, ht = nethttp.TraceRequest(
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parentSpan.Tracer(),
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httpReq,
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nethttp.OperationName("Remote Read"),
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nethttp.ClientTrace(false),
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)
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defer ht.Finish()
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}
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start := time.Now()
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httpResp, err := c.Client.Do(httpReq)
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if err != nil {
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return nil, errors.Wrap(err, "error sending request")
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}
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defer func() {
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io.Copy(ioutil.Discard, httpResp.Body)
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httpResp.Body.Close()
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}()
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c.readQueriesDuration.Observe(time.Since(start).Seconds())
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c.readQueriesTotal.WithLabelValues(strconv.Itoa(httpResp.StatusCode)).Inc()
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compressed, err = ioutil.ReadAll(httpResp.Body)
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if err != nil {
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return nil, errors.Wrap(err, fmt.Sprintf("error reading response. HTTP status code: %s", httpResp.Status))
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}
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if httpResp.StatusCode/100 != 2 {
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return nil, errors.Errorf("remote server %s returned HTTP status %s: %s", c.url.String(), httpResp.Status, strings.TrimSpace(string(compressed)))
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}
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uncompressed, err := snappy.Decode(nil, compressed)
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if err != nil {
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return nil, errors.Wrap(err, "error reading response")
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}
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var resp prompb.ReadResponse
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err = proto.Unmarshal(uncompressed, &resp)
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if err != nil {
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return nil, errors.Wrap(err, "unable to unmarshal response body")
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}
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if len(resp.Results) != len(req.Queries) {
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return nil, errors.Errorf("responses: want %d, got %d", len(req.Queries), len(resp.Results))
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}
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return resp.Results[0], nil
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}
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