force http2 for clients and increase http2 server concurrency

Author: TymKh

proxy/receiver_servers.go

@@ -16,6 +16,7 @@ var (
 	HTTPDefaultIdleTimeout             = time.Duration(cli.GetEnvInt("HTTP_IDLE_TIMEOUT_SEC", 3600)) * time.Second
 	HTTP2DefaultMaxUploadPerConnection = int32(cli.GetEnvInt("HTTP2_MAX_UPLOAD_PER_CONN", 32<<20))  // 32MiB
 	HTTP2DefaultMaxUploadPerStream     = int32(cli.GetEnvInt("HTTP2_MAX_UPLOAD_PER_STREAM", 8<<20)) // 8MiB
+	HTTP2DefaultMaxConcurrentStreams   = uint32(cli.GetEnvInt("HTTP2_MAX_CONCURRENT_STREAMS", 4096))
 )
 
 type ReceiverProxyServers struct {
@@ -35,6 +36,7 @@ func StartReceiverServers(proxy *ReceiverProxy, userListenAddress, systemListenA
 		IdleTimeout:  HTTPDefaultIdleTimeout,
 	}
 	userH2 := http2.Server{
+		MaxConcurrentStreams:         HTTP2DefaultMaxConcurrentStreams,
 		MaxUploadBufferPerConnection: HTTP2DefaultMaxUploadPerConnection,
 		MaxUploadBufferPerStream:     HTTP2DefaultMaxUploadPerStream,
 	}
@@ -54,6 +56,7 @@ func StartReceiverServers(proxy *ReceiverProxy, userListenAddress, systemListenA
 		IdleTimeout:  HTTPDefaultIdleTimeout,
 	}
 	systemH2 := http2.Server{
+		MaxConcurrentStreams:         HTTP2DefaultMaxConcurrentStreams,
 		MaxUploadBufferPerConnection: HTTP2DefaultMaxUploadPerConnection,
 		MaxUploadBufferPerStream:     HTTP2DefaultMaxUploadPerStream,
 	}

proxy/utils.go

@@ -32,12 +32,19 @@ func createTransportForSelfSignedCert(certPEM []byte) (*http.Transport, error) {
 	if ok := certPool.AppendCertsFromPEM(certPEM); !ok {
 		return nil, errCertificate
 	}
-	return &http.Transport{
+	tr := &http.Transport{
 		TLSClientConfig: &tls.Config{
 			RootCAs:    certPool,
 			MinVersion: tls.VersionTLS12,
 		},
-	}, nil
+		ForceAttemptHTTP2: true,
+	}
+	// Is required due to TLSCLientConfig field specified
+	err := http2.ConfigureTransport(tr)
+	if err != nil {
+		return nil, err
+	}
+	return tr, nil
 }
 
 func HTTPClientWithMaxConnections(maxOpenConnections int) *http.Client {