Reuse http transport

Signed-off-by: Matthias Fehr <matthias@monostream.com>
(cherry picked from commit aa33f4f)

pkg/getter/httpgetter.go

@@ -31,7 +31,8 @@ import (
 
 // HTTPGetter is the default HTTP(/S) backend handler
 type HTTPGetter struct {
-	opts options
+	opts      options
+	transport *http.Transport
 }
 
 // Get performs a Get from repo.Getter and returns the body.
@@ -106,10 +107,13 @@ func NewHTTPGetter(options ...Option) (Getter, error) {
 }
 
 func (g *HTTPGetter) httpClient() (*http.Client, error) {
-	transport := &http.Transport{
-		DisableCompression: true,
-		Proxy:              http.ProxyFromEnvironment,
+	if g.transport == nil {
+		g.transport = &http.Transport{
+			DisableCompression: true,
+			Proxy:              http.ProxyFromEnvironment,
+		}
 	}
+
 	if (g.opts.certFile != "" && g.opts.keyFile != "") || g.opts.caFile != "" {
 		tlsConf, err := tlsutil.NewClientTLS(g.opts.certFile, g.opts.keyFile, g.opts.caFile)
 		if err != nil {
@@ -123,21 +127,21 @@ func (g *HTTPGetter) httpClient() (*http.Client, error) {
 		}
 		tlsConf.ServerName = sni
 
-		transport.TLSClientConfig = tlsConf
+		g.transport.TLSClientConfig = tlsConf
 	}
 
 	if g.opts.insecureSkipVerifyTLS {
-		if transport.TLSClientConfig == nil {
-			transport.TLSClientConfig = &tls.Config{
+		if g.transport.TLSClientConfig == nil {
+			g.transport.TLSClientConfig = &tls.Config{
 				InsecureSkipVerify: true,
 			}
 		} else {
-			transport.TLSClientConfig.InsecureSkipVerify = true
+			g.transport.TLSClientConfig.InsecureSkipVerify = true
 		}
 	}
 
 	client := &http.Client{
-		Transport: transport,
+		Transport: g.transport,
 		Timeout:   g.opts.timeout,
 	}