From 6994a3daaa0acfc8431e33da535c85e23ab319e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Sun, 21 Jun 2015 20:23:37 +0300
Subject: [PATCH] p2p: instrument P2P networking layer

---
 p2p/dial.go    |  4 +++-
 p2p/metrics.go | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 p2p/server.go  |  6 ++++--
 3 files changed, 56 insertions(+), 3 deletions(-)
 create mode 100644 p2p/metrics.go

diff --git a/p2p/dial.go b/p2p/dial.go
index b82d6d1f5..45cd8116b 100644
--- a/p2p/dial.go
+++ b/p2p/dial.go
@@ -196,7 +196,9 @@ func (t *dialTask) Do(srv *Server) {
 		glog.V(logger.Detail).Infof("dial error: %v", err)
 		return
 	}
-	srv.setupConn(fd, t.flags, t.dest)
+	mfd := newMeteredConn(fd, false)
+
+	srv.setupConn(mfd, t.flags, t.dest)
 }
 func (t *dialTask) String() string {
 	return fmt.Sprintf("%v %x %v:%d", t.flags, t.dest.ID[:8], t.dest.IP, t.dest.TCP)
diff --git a/p2p/metrics.go b/p2p/metrics.go
new file mode 100644
index 000000000..fbe5b1e90
--- /dev/null
+++ b/p2p/metrics.go
@@ -0,0 +1,49 @@
+// Contains the meters and timers used by the networking layer.
+
+package p2p
+
+import (
+	"net"
+
+	"github.com/rcrowley/go-metrics"
+)
+
+var (
+	ingressConnectMeter = metrics.GetOrRegisterMeter("p2p/InboundConnects", metrics.DefaultRegistry)
+	ingressTrafficMeter = metrics.GetOrRegisterMeter("p2p/InboundTraffic", metrics.DefaultRegistry)
+	egressConnectMeter  = metrics.GetOrRegisterMeter("p2p/OutboundConnects", metrics.DefaultRegistry)
+	egressTrafficMeter  = metrics.GetOrRegisterMeter("p2p/OutboundTraffic", metrics.DefaultRegistry)
+)
+
+// meteredConn is a wrapper around a network TCP connection that meters both the
+// inbound and outbound network traffic.
+type meteredConn struct {
+	*net.TCPConn // Network connection to wrap with metering
+}
+
+// newMeteredConn creates a new metered connection, also bumping the ingress or
+// egress connection meter.
+func newMeteredConn(conn net.Conn, ingress bool) net.Conn {
+	if ingress {
+		ingressConnectMeter.Mark(1)
+	} else {
+		egressConnectMeter.Mark(1)
+	}
+	return &meteredConn{conn.(*net.TCPConn)}
+}
+
+// Read delegates a network read to the underlying connection, bumping the ingress
+// traffic meter along the way.
+func (c *meteredConn) Read(b []byte) (n int, err error) {
+	n, err = c.TCPConn.Read(b)
+	ingressTrafficMeter.Mark(int64(n))
+	return
+}
+
+// Write delegates a network write to the underlying connection, bumping the
+// egress traffic meter along the way.
+func (c *meteredConn) Write(b []byte) (n int, err error) {
+	n, err = c.TCPConn.Write(b)
+	egressTrafficMeter.Mark(int64(n))
+	return
+}
diff --git a/p2p/server.go b/p2p/server.go
index 5eff70345..9078841a8 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -548,9 +548,11 @@ func (srv *Server) listenLoop() {
 		if err != nil {
 			return
 		}
-		glog.V(logger.Debug).Infof("Accepted conn %v\n", fd.RemoteAddr())
+		mfd := newMeteredConn(fd, true)
+
+		glog.V(logger.Debug).Infof("Accepted conn %v\n", mfd.RemoteAddr())
 		go func() {
-			srv.setupConn(fd, inboundConn, nil)
+			srv.setupConn(mfd, inboundConn, nil)
 			slots <- struct{}{}
 		}()
 	}