p2p: better dial/serve success metrics (#31629)

Our previous success metrics gave success even if a peer disconnected
right after connection. These metrics only count peers that stayed
connected for at least 1 min. The 1 min limit is an arbitrary choice. We do
not use this for decision logic, only statistics.

p2p/metrics.go

@@ -51,6 +51,10 @@ var (
 	dialSuccessMeter    = metrics.NewRegisteredMeter("p2p/dials/success", nil)
 	dialConnectionError = metrics.NewRegisteredMeter("p2p/dials/error/connection", nil)
 
+	// count peers that stayed connected for at least 1 min
+	serve1MinSuccessMeter = metrics.NewRegisteredMeter("p2p/serves/success/1min", nil)
+	dial1MinSuccessMeter  = metrics.NewRegisteredMeter("p2p/dials/success/1min", nil)
+
 	// handshake error meters
 	dialTooManyPeers        = metrics.NewRegisteredMeter("p2p/dials/error/saturated", nil)
 	dialAlreadyConnected    = metrics.NewRegisteredMeter("p2p/dials/error/known", nil)

p2p/peer.go

@@ -254,6 +254,8 @@ func (p *Peer) run() (remoteRequested bool, err error) {
 	p.wg.Add(2)
 	go p.readLoop(readErr)
 	go p.pingLoop()
+	live1min := time.NewTimer(1 * time.Minute)
+	defer live1min.Stop()
 
 	// Start all protocol handlers.
 	writeStart <- struct{}{}
@@ -285,6 +287,12 @@ loop:
 		case err = <-p.disc:
 			reason = discReasonForError(err)
 			break loop
+		case <-live1min.C:
+			if p.Inbound() {
+				serve1MinSuccessMeter.Mark(1)
+			} else {
+				dial1MinSuccessMeter.Mark(1)
+			}
 		}
 	}