feat(tsdb): default tsdb httpclient

pkg/tsdb/graphite/graphite.go

@@ -2,7 +2,6 @@ package graphite
 
 import (
 	"context"
-	"crypto/tls"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -10,7 +9,6 @@ import (
 	"net/url"
 	"path"
 	"strings"
-	"time"
 
 	"golang.org/x/net/context/ctxhttp"
 
@@ -36,14 +34,7 @@ func init() {
 	glog = log.New("tsdb.graphite")
 	tsdb.RegisterExecutor("graphite", NewGraphiteExecutor)
 
-	tr := &http.Transport{
+	HttpClient = tsdb.GetDefaultClient()
-		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
-	}
-
-	HttpClient = &http.Client{
-		Timeout:   time.Duration(15 * time.Second),
-		Transport: tr,
-	}
 }
 
 func (e *GraphiteExecutor) Execute(ctx context.Context, queries tsdb.QuerySlice, context *tsdb.QueryContext) *tsdb.BatchResult {

pkg/tsdb/http.go

@@ -0,0 +1,29 @@
+package tsdb
+
+import (
+	"crypto/tls"
+	"net"
+	"net/http"
+	"time"
+)
+
+func GetDefaultClient() *http.Client {
+	tr := &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+		}).DialContext,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+	}
+
+	return &http.Client{
+		Timeout:   time.Duration(30 * time.Second),
+		Transport: tr,
+	}
+}

pkg/tsdb/influxdb/influxdb.go

@@ -2,13 +2,11 @@ package influxdb
 
 import (
 	"context"
-	"crypto/tls"
 	"encoding/json"
 	"fmt"
 	"net/http"
 	"net/url"
 	"path"
-	"time"
 
 	"golang.org/x/net/context/ctxhttp"
 
@@ -41,14 +39,7 @@ func init() {
 	glog = log.New("tsdb.influxdb")
 	tsdb.RegisterExecutor("influxdb", NewInfluxDBExecutor)
 
-	tr := &http.Transport{
+	HttpClient = tsdb.GetDefaultClient()
-		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
-	}
-
-	HttpClient = &http.Client{
-		Timeout:   time.Duration(15 * time.Second),
-		Transport: tr,
-	}
 }
 
 func (e *InfluxDBExecutor) Execute(ctx context.Context, queries tsdb.QuerySlice, context *tsdb.QueryContext) *tsdb.BatchResult {

pkg/tsdb/opentsdb/opentsdb.go

@@ -2,19 +2,17 @@ package opentsdb
 
 import (
 	"context"
-	"crypto/tls"
 	"fmt"
 	"path"
 	"strconv"
 	"strings"
-	"time"
 
 	"golang.org/x/net/context/ctxhttp"
 
+	"encoding/json"
 	"io/ioutil"
 	"net/http"
 	"net/url"
-	"encoding/json"
 
 	"gopkg.in/guregu/null.v3"
 
@@ -40,14 +38,7 @@ func init() {
 	plog = log.New("tsdb.opentsdb")
 	tsdb.RegisterExecutor("opentsdb", NewOpenTsdbExecutor)
 
-	tr := &http.Transport{
+	HttpClient = tsdb.GetDefaultClient()
-		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
-	}
-
-	HttpClient = &http.Client{
-		Timeout:   time.Duration(15 * time.Second),
-		Transport: tr,
-	}
 }
 
 func (e *OpenTsdbExecutor) Execute(ctx context.Context, queries tsdb.QuerySlice, queryContext *tsdb.QueryContext) *tsdb.BatchResult {
@@ -152,7 +143,7 @@ func (e *OpenTsdbExecutor) parseResponse(query OpenTsdbQuery, res *http.Response
 	return queryResults, nil
 }
 
-func (e *OpenTsdbExecutor) buildMetric(query *tsdb.Query) (map[string]interface{}) {
+func (e *OpenTsdbExecutor) buildMetric(query *tsdb.Query) map[string]interface{} {
 
 	metric := make(map[string]interface{})
 

pkg/tsdb/prometheus/prometheus.go

@@ -3,7 +3,6 @@ package prometheus
 import (
 	"context"
 	"fmt"
-	"net/http"
 	"regexp"
 	"strings"
 	"time"
@@ -26,7 +25,6 @@ func NewPrometheusExecutor(dsInfo *tsdb.DataSourceInfo) tsdb.Executor {
 
 var (
 	plog log.Logger
-	HttpClient http.Client
 )
 
 func init() {