roughed-in metricsConn for backend (#74)

endpoints/backend/http.go

@@ -1,12 +1,14 @@
 package backend
 
 import (
+	"context"
 	"github.com/openziti-test-kitchen/zrok/util"
 	"github.com/openziti/sdk-golang/ziti"
 	"github.com/openziti/sdk-golang/ziti/config"
 	"github.com/openziti/sdk-golang/ziti/edge"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
+	"net"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
@@ -67,7 +69,11 @@ func newReverseProxy(target string) (*httputil.ReverseProxy, error) {
 		return nil, err
 	}
 
+	tpt := http.DefaultTransport.(*http.Transport).Clone()
+	tpt.DialContext = metricsDial
+
 	proxy := httputil.NewSingleHostReverseProxy(targetURL)
+	proxy.Transport = tpt
 	director := proxy.Director
 	proxy.Director = func(req *http.Request) {
 		director(req)
@@ -80,3 +86,12 @@ func newReverseProxy(target string) (*httputil.ReverseProxy, error) {
 
 	return proxy, nil
 }
+
+func metricsDial(_ context.Context, network string, addr string) (net.Conn, error) {
+	conn, err := net.Dial(network, addr)
+	if err != nil {
+		return conn, err
+	}
+	logrus.Infof("returned wrapped metricsConn")
+	return newMetricsConn("self", conn), nil
+}

endpoints/backend/metrics.go

@@ -0,0 +1,52 @@
+package backend
+
+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)
+}