Use cache for http.client in tsdb package. (#6833)

* datasource: move caching closer to datasource struct

* tsdb: use cached version of datasource http transport

closes #6825

pkg/api/dataproxy.go

@@ -1,13 +1,9 @@
 package api
 
 import (
-	"crypto/tls"
-	"crypto/x509"
-	"net"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
-	"sync"
 	"time"
 
 	"github.com/grafana/grafana/pkg/api/cloudwatch"
@@ -19,75 +15,6 @@ import (
 	"github.com/grafana/grafana/pkg/util"
 )
 
-type proxyTransportCache struct {
-	cache map[int64]cachedTransport
-	sync.Mutex
-}
-
-type cachedTransport struct {
-	updated time.Time
-
-	*http.Transport
-}
-
-var ptc = proxyTransportCache{
-	cache: make(map[int64]cachedTransport),
-}
-
-func DataProxyTransport(ds *m.DataSource) (*http.Transport, error) {
-	ptc.Lock()
-	defer ptc.Unlock()
-
-	if t, present := ptc.cache[ds.Id]; present && ds.Updated.Equal(t.updated) {
-		return t.Transport, nil
-	}
-
-	transport := &http.Transport{
-		TLSClientConfig: &tls.Config{
-			InsecureSkipVerify: true,
-		},
-		Proxy: http.ProxyFromEnvironment,
-		Dial: (&net.Dialer{
-			Timeout:   30 * time.Second,
-			KeepAlive: 30 * time.Second,
-		}).Dial,
-		TLSHandshakeTimeout: 10 * time.Second,
-	}
-
-	var tlsAuth, tlsAuthWithCACert bool
-	if ds.JsonData != nil {
-		tlsAuth = ds.JsonData.Get("tlsAuth").MustBool(false)
-		tlsAuthWithCACert = ds.JsonData.Get("tlsAuthWithCACert").MustBool(false)
-	}
-
-	if tlsAuth {
-		transport.TLSClientConfig.InsecureSkipVerify = false
-
-		decrypted := ds.SecureJsonData.Decrypt()
-
-		if tlsAuthWithCACert && len(decrypted["tlsCACert"]) > 0 {
-			caPool := x509.NewCertPool()
-			ok := caPool.AppendCertsFromPEM([]byte(decrypted["tlsCACert"]))
-			if ok {
-				transport.TLSClientConfig.RootCAs = caPool
-			}
-		}
-
-		cert, err := tls.X509KeyPair([]byte(decrypted["tlsClientCert"]), []byte(decrypted["tlsClientKey"]))
-		if err != nil {
-			return nil, err
-		}
-		transport.TLSClientConfig.Certificates = []tls.Certificate{cert}
-	}
-
-	ptc.cache[ds.Id] = cachedTransport{
-		Transport: transport,
-		updated:   ds.Updated,
-	}
-
-	return transport, nil
-}
-
 func NewReverseProxy(ds *m.DataSource, proxyPath string, targetUrl *url.URL) *httputil.ReverseProxy {
 	director := func(req *http.Request) {
 		req.URL.Scheme = targetUrl.Scheme
@@ -189,7 +116,7 @@ func ProxyDataSourceRequest(c *middleware.Context) {
 	}
 
 	proxy := NewReverseProxy(ds, proxyPath, targetUrl)
-	proxy.Transport, err = DataProxyTransport(ds)
+	proxy.Transport, err = ds.GetHttpTransport()
 	if err != nil {
 		c.JsonApiErr(400, "Unable to load TLS certificate", err)
 		return