'metricsConn' net.Conn wrapper to capture service metrics in the frontend (#74)

endpoints/frontend/http.go

@@ -65,7 +65,11 @@ type zitiDialContext struct {
 
 func (self *zitiDialContext) Dial(_ context.Context, _ string, addr string) (net.Conn, error) {
 	svcName := strings.Split(addr, ":")[0] // ignore :port (we get passed 'host:port')
-	return self.ctx.Dial(svcName)
+	conn, err := self.ctx.Dial(svcName)
+	if err != nil {
+		return conn, err
+	}
+	return newMetricsConn(svcName, conn), nil
 }
 
 func newServiceProxy(cfg *Config, ctx ziti.Context) (*httputil.ReverseProxy, error) {

endpoints/frontend/metrics.go

@@ -0,0 +1,52 @@
+package frontend
+
+import (
+	"github.com/sirupsen/logrus"
+	"net"
+	"time"
+)
+
+type metricsConn struct {
+	id   string
+	conn net.Conn
+}
+
+func newMetricsConn(id string, conn net.Conn) *metricsConn {
+	return &metricsConn{id, conn}
+}
+
+func (mc *metricsConn) Read(b []byte) (n int, err error) {
+	n, err = mc.conn.Read(b)
+	logrus.Infof("[%v] => %d", mc.id, n)
+	return n, err
+}
+
+func (mc *metricsConn) Write(b []byte) (n int, err error) {
+	n, err = mc.conn.Write(b)
+	logrus.Infof("[%v] <= %d", mc.id, n)
+	return n, err
+}
+
+func (mc *metricsConn) Close() error {
+	return mc.conn.Close()
+}
+
+func (mc *metricsConn) LocalAddr() net.Addr {
+	return mc.conn.LocalAddr()
+}
+
+func (mc *metricsConn) RemoteAddr() net.Addr {
+	return mc.conn.RemoteAddr()
+}
+
+func (mc *metricsConn) SetDeadline(t time.Time) error {
+	return mc.conn.SetDeadline(t)
+}
+
+func (mc *metricsConn) SetReadDeadline(t time.Time) error {
+	return mc.conn.SetReadDeadline(t)
+}
+
+func (mc *metricsConn) SetWriteDeadline(t time.Time) error {
+	return mc.conn.SetWriteDeadline(t)
+}