sidecar: allow custom http con pool size fix thanos-io#1953

Signed-off-by: Brett Jones <[email protected]>

CHANGELOG.md

@@ -13,6 +13,7 @@ We use *breaking* word for marking changes that are not backward compatible (rel
 
 ### Fixed
 
+- [#1955](https://github.com/thanos-io/thanos/pull/1955) Sidecar: enable command line flag to set http connection pool size `--prometheus.connection-pool-size`
 - [#1919](https://github.com/thanos-io/thanos/issues/1919) Compactor: Fixed potential data loss when uploading older blocks, or upload taking long time while compactor is
 running.
 - [#1937](https://github.com/thanos-io/thanos/pull/1937) Compactor: Improved synchronization of meta JSON files.

cmd/thanos/sidecar.go

@@ -45,6 +45,9 @@ func registerSidecar(m map[string]setupFunc, app *kingpin.Application) {
 	promReadyTimeout := cmd.Flag("prometheus.ready_timeout", "Maximum time to wait for the Prometheus instance to start up").
 		Default("10m").Duration()
 
+	connectionPoolSize := cmd.Flag("prometheus.connection-pool-size", "sets the MaxIdleConnsPerHost and MaxIdleConns when connecting to prometheus").
+		Default("100").Int()
+
 	dataDir := cmd.Flag("tsdb.path", "Data directory of TSDB.").
 		Default("./data").String()
 
@@ -95,6 +98,7 @@ func registerSidecar(m map[string]setupFunc, app *kingpin.Application) {
 			*ignoreBlockSize,
 			component.Sidecar,
 			*minTime,
+			*connectionPoolSize,
 		)
 	}
 }
@@ -120,6 +124,7 @@ func runSidecar(
 	ignoreBlockSize bool,
 	comp component.Component,
 	limitMinTime thanosmodel.TimeOrDurationValue,
+	connectionPoolSize int,
 ) error {
 	var m = &promMetadata{
 		promURL: promURL,
@@ -244,7 +249,7 @@ func runSidecar(
 
 	{
 		promStore, err := store.NewPrometheusStore(
-			logger, nil, promURL, component.Sidecar, m.Labels, m.Timestamps)
+			logger, nil, promURL, component.Sidecar, m.Labels, m.Timestamps, connectionPoolSize)
 		if err != nil {
 			return errors.Wrap(err, "create Prometheus store")
 		}

docs/components/sidecar.md

@@ -126,6 +126,9 @@ Flags:
       --prometheus.ready_timeout=10m
                                  Maximum time to wait for the Prometheus
                                  instance to start up
+      --prometheus.connection-pool-size=100
+                                 sets the MaxIdleConnsPerHost and MaxIdleConns
+                                 when connecting to prometheus
       --tsdb.path="./data"       Data directory of TSDB.
       --reloader.config-file=""  Config file watched by the reloader.
       --reloader.config-envsubst-file=""

pkg/store/prometheus.go

@@ -73,13 +73,18 @@ func NewPrometheusStore(
 	component component.StoreAPI,
 	externalLabels func() labels.Labels,
 	timestamps func() (mint int64, maxt int64),
+	connectionPoolSize int,
 ) (*PrometheusStore, error) {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
 	if client == nil {
+		t := http.DefaultTransport.(*http.Transport)
+		t.MaxIdleConnsPerHost = connectionPoolSize
+		t.MaxIdleConns = connectionPoolSize
+
 		client = &http.Client{
-			Transport: tracing.HTTPTripperware(logger, http.DefaultTransport),
+			Transport: tracing.HTTPTripperware(logger, t),
 		}
 	}
 	p := &PrometheusStore{

pkg/store/prometheus_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"net/http"
 	"net/url"
 	"testing"
 	"time"
@@ -59,7 +60,7 @@ func testPrometheusStoreSeriesE2e(t *testing.T, prefix string) {
 	limitMinT := int64(0)
 	proxy, err := NewPrometheusStore(nil, nil, u, component.Sidecar,
 		func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-		func() (int64, int64) { return limitMinT, -1 }) // Maxt does not matter.
+		func() (int64, int64) { return limitMinT, -1 }, http.DefaultMaxIdleConnsPerHost) // Maxt does not matter.
 	testutil.Ok(t, err)
 
 	// Query all three samples except for the first one. Since we round up queried data
@@ -211,7 +212,7 @@ func TestPrometheusStore_SeriesLabels_e2e(t *testing.T) {
 	limitMinT := int64(0)
 	proxy, err := NewPrometheusStore(nil, nil, u, component.Sidecar,
 		func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-		func() (int64, int64) { return limitMinT, -1 }) // Maxt does not matter.
+		func() (int64, int64) { return limitMinT, -1 }, http.DefaultMaxIdleConnsPerHost) // Maxt does not matter.
 	testutil.Ok(t, err)
 
 	{
@@ -284,7 +285,7 @@ func TestPrometheusStore_LabelValues_e2e(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", p.Addr()))
 	testutil.Ok(t, err)
 
-	proxy, err := NewPrometheusStore(nil, nil, u, component.Sidecar, getExternalLabels, nil)
+	proxy, err := NewPrometheusStore(nil, nil, u, component.Sidecar, getExternalLabels, nil, http.DefaultMaxIdleConnsPerHost)
 	testutil.Ok(t, err)
 
 	resp, err := proxy.LabelValues(ctx, &storepb.LabelValuesRequest{
@@ -318,7 +319,7 @@ func TestPrometheusStore_ExternalLabelValues_e2e(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", p.Addr()))
 	testutil.Ok(t, err)
 
-	proxy, err := NewPrometheusStore(nil, nil, u, component.Sidecar, getExternalLabels, nil)
+	proxy, err := NewPrometheusStore(nil, nil, u, component.Sidecar, getExternalLabels, nil, http.DefaultMaxIdleConnsPerHost)
 	testutil.Ok(t, err)
 
 	resp, err := proxy.LabelValues(ctx, &storepb.LabelValuesRequest{
@@ -364,8 +365,7 @@ func TestPrometheusStore_Series_MatchExternalLabel_e2e(t *testing.T) {
 
 	proxy, err := NewPrometheusStore(nil, nil, u, component.Sidecar,
 		func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-		func() (int64, int64) { return 0, math.MaxInt64 },
-	)
+		func() (int64, int64) { return 0, math.MaxInt64 }, http.DefaultMaxIdleConnsPerHost)
 	testutil.Ok(t, err)
 	srv := newStoreSeriesServer(ctx)
 
@@ -410,8 +410,7 @@ func TestPrometheusStore_Info(t *testing.T) {
 
 	proxy, err := NewPrometheusStore(nil, nil, nil, component.Sidecar,
 		func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-		func() (int64, int64) { return 123, 456 },
-	)
+		func() (int64, int64) { return 123, 456 }, http.DefaultMaxIdleConnsPerHost)
 	testutil.Ok(t, err)
 
 	resp, err := proxy.Info(ctx, &storepb.InfoRequest{})
@@ -489,8 +488,7 @@ func TestPrometheusStore_Series_SplitSamplesIntoChunksWithMaxSizeOfUint16_e2e(t
 
 		proxy, err := NewPrometheusStore(nil, nil, u, component.Sidecar,
 			func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-			func() (int64, int64) { return 0, math.MaxInt64 },
-		)
+			func() (int64, int64) { return 0, math.MaxInt64 }, http.DefaultMaxIdleConnsPerHost)
 		testutil.Ok(t, err)
 
 		// We build chunks only for SAMPLES method. Make sure we ask for SAMPLES only.