Move server to proxy implementation

api/http/proxy/factory/docker_compose.go

@@ -1,6 +1,9 @@
 package factory
 
 import (
+	"fmt"
+	"log"
+	"net"
 	"net/http"
 	"net/url"
 
@@ -9,7 +12,13 @@ import (
 	"github.com/portainer/portainer/api/http/proxy/factory/dockercompose"
 )
 
-func (factory *ProxyFactory) NewDockerComposeAgentProxy(endpoint *portainer.Endpoint) (http.Handler, error) {
+// ProxyServer provide an extedned proxy with a local server to forward requests
+type ProxyServer struct {
+	server http.Server
+	Port   int
+}
+
+func (factory *ProxyFactory) NewDockerComposeAgentProxy(endpoint *portainer.Endpoint) (*ProxyServer, error) {
 
 	endpointURL, err := url.Parse(endpoint.URL)
 	if err != nil {
@@ -33,9 +42,45 @@ func (factory *ProxyFactory) NewDockerComposeAgentProxy(endpoint *portainer.Endp
 
 	proxy.Transport = dockercompose.NewAgentTransport(factory.signatureService, httpTransport)
 
-	return proxy, nil
+	proxyServer := &ProxyServer{
+		http.Server{
+			Handler: proxy,
+		},
+		0,
+	}
+
+	return proxyServer, proxyServer.Start()
 }
 
 func (factory *ProxyFactory) GetReverseTunnel(endpoint *portainer.Endpoint) *portainer.TunnelDetails {
 	return factory.reverseTunnelService.GetTunnelDetails(endpoint.ID)
 }
+
+func (proxy *ProxyServer) Start() error {
+	listener, err := net.Listen("tcp", ":0")
+	if err != nil {
+		return err
+	}
+
+	shutdownChan := make(chan error, 1)
+	proxy.Port = listener.Addr().(*net.TCPAddr).Port
+	go func() {
+
+		log.Printf("Starting Proxy server on %s...\n", fmt.Sprintf("http://127.0.0.1:%d", proxy.Port))
+
+		err := proxy.server.Serve(listener)
+		log.Printf("Proxy Server exited with '%v' error\n", err)
+
+		if err != http.ErrServerClosed {
+			log.Printf("Put '%v' error returned by Proxy Server to shutdown channel\n", proxy.Port)
+			shutdownChan <- err
+		}
+	}()
+
+	return nil
+}
+
+// Close the server proxy
+func (proxy *ProxyServer) Close() {
+	proxy.server.Close()
+}