From 3b2aa5880ab7e85587134ac011f02034e1441523 Mon Sep 17 00:00:00 2001
From: Lars Gierth <larsg@systemli.org>
Date: Tue, 23 Jun 2015 02:11:04 +0200
Subject: [PATCH] swarm: export ipfs_p2p_peers_total metric

---
 p2p/net/swarm/swarm.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/p2p/net/swarm/swarm.go b/p2p/net/swarm/swarm.go
index 4fe45df8549f..a451b9b3f642 100644
--- a/p2p/net/swarm/swarm.go
+++ b/p2p/net/swarm/swarm.go
@@ -20,12 +20,20 @@ import (
 	pst "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-peerstream/transport"
 	psy "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-peerstream/transport/yamux"
 	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
+	prom "github.com/prometheus/client_golang/prometheus"
 )
 
 var log = eventlog.Logger("swarm2")
 
 var PSTransport pst.Transport
 
+var peersTotal = prom.NewGauge(prom.GaugeOpts{
+	Namespace: "ipfs",
+	Subsystem: "p2p",
+	Name:      "peers_total",
+	Help:      "Number of connected peers",
+})
+
 func init() {
 	tpt := *psy.DefaultTransport
 	tpt.MaxStreamWindowSize = 512 * 1024
@@ -82,6 +90,8 @@ func NewSwarm(ctx context.Context, listenAddrs []ma.Multiaddr,
 	s.cg.SetTeardown(s.teardown)
 	s.SetConnHandler(nil) // make sure to setup our own conn handler.
 
+	prom.MustRegister(peersTotal)
+
 	return s, s.listen(listenAddrs)
 }
 
@@ -260,10 +270,12 @@ type ps2netNotifee struct {
 
 func (n *ps2netNotifee) Connected(c *ps.Conn) {
 	n.not.Connected(n.net, inet.Conn((*Conn)(c)))
+	peersTotal.Inc()
 }
 
 func (n *ps2netNotifee) Disconnected(c *ps.Conn) {
 	n.not.Disconnected(n.net, inet.Conn((*Conn)(c)))
+	peersTotal.Dec()
 }
 
 func (n *ps2netNotifee) OpenedStream(s *ps.Stream) {