Add metrics for the routing table

dht.go

@@ -8,6 +8,10 @@ import (
 	"sync"
 	"time"
 
+	"go.opencensus.io/metric/metricdata"
+
+	"go.opencensus.io/stats"
+
 	"github.com/libp2p/go-libp2p-kad-dht/metrics"
 	"go.opencensus.io/tag"
 
@@ -133,14 +137,6 @@ func NewDHTClient(ctx context.Context, h host.Host, dstore ds.Batching) *IpfsDHT
 func makeDHT(ctx context.Context, h host.Host, dstore ds.Batching, protocols []protocol.ID) *IpfsDHT {
 	rt := kb.NewRoutingTable(KValue, kb.ConvertPeerID(h.ID()), time.Minute, h.Peerstore())
 
-	cmgr := h.ConnManager()
-	rt.PeerAdded = func(p peer.ID) {
-		cmgr.TagPeer(p, "kbucket", 5)
-	}
-	rt.PeerRemoved = func(p peer.ID) {
-		cmgr.UntagPeer(p, "kbucket")
-	}
-
 	dht := &IpfsDHT{
 		datastore:    dstore,
 		self:         h.ID(),
@@ -153,13 +149,38 @@ func makeDHT(ctx context.Context, h host.Host, dstore ds.Batching, protocols []p
 		protocols:    protocols,
 	}
 	dht.ctx = dht.withLocalTags(ctx)
+
+	cmgr := h.ConnManager()
+	rt.PeerAdded = func(p peer.ID) {
+		cmgr.TagPeer(p, "kbucket", 5)
+		stats.Record(dht.ctx, metrics.RoutingTablePeersAdded.M(1))
+	}
+	rt.PeerRemoved = func(p peer.ID) {
+		cmgr.UntagPeer(p, "kbucket")
+		stats.Record(dht.ctx, metrics.RoutingTablePeersRemoved.M(1))
+	}
+	metrics.RoutingTableNumEntries.UpsertEntry(
+		func() int64 {
+			return int64(rt.Size())
+		},
+		metricdata.LabelValue{dht.localPeerIdTagValue(), true},
+		metricdata.LabelValue{dht.instanceIdTagValue(), true},
+	)
 	return dht
 }
 
+func (dht *IpfsDHT) localPeerIdTagValue() string {
+	return dht.self.String()
+}
+
+func (dht *IpfsDHT) instanceIdTagValue() string {
+	return fmt.Sprintf("%p", dht)
+}
+
 func (dht *IpfsDHT) tagMutators() []tag.Mutator {
 	return []tag.Mutator{
-		tag.Upsert(metrics.KeyLocalPeerID, dht.self.String()),
-		tag.Upsert(metrics.KeyInstanceID, fmt.Sprintf("%p", dht)),
+		tag.Upsert(metrics.KeyLocalPeerID, dht.localPeerIdTagValue()),
+		tag.Upsert(metrics.KeyInstanceID, dht.instanceIdTagValue()),
 	}
 }
 

metrics/opencensus.go

@@ -2,6 +2,8 @@ package metrics
 
 import (
 	pb "github.com/libp2p/go-libp2p-kad-dht/pb"
+	"go.opencensus.io/metric"
+	"go.opencensus.io/metric/metricdata"
 	"go.opencensus.io/stats"
 	"go.opencensus.io/stats/view"
 	"go.opencensus.io/tag"
@@ -40,6 +42,14 @@ var (
 		"Time between wanting to send a message, and writing it",
 		stats.UnitMilliseconds,
 	)
+
+	RoutingTablePeersAdded   = stats.Int64(namePrefix+"routing_table_peers_added", "", stats.UnitDimensionless)
+	RoutingTablePeersRemoved = stats.Int64(namePrefix+"routing_table_peers_removed", "", stats.UnitDimensionless)
+
+	GaugeRegistry             = metric.NewRegistry()
+	RoutingTableNumEntries, _ = GaugeRegistry.AddInt64DerivedGauge(
+		"routing_table_num_entries", "", metricdata.UnitDimensionless,
+		KeyLocalPeerID.Name(), KeyInstanceID.Name())
 )
 
 var Views = []*view.View{{
@@ -70,4 +80,12 @@ var Views = []*view.View{{
 	Measure:     MessageWriteLatencyMs,
 	TagKeys:     []tag.Key{KeyMessageType, KeyLocalPeerID, KeyInstanceID},
 	Aggregation: view.Distribution(0, 1, 10, 100),
+}, {
+	Measure:     RoutingTablePeersAdded,
+	TagKeys:     []tag.Key{KeyLocalPeerID, KeyInstanceID},
+	Aggregation: view.Count(),
+}, {
+	Measure:     RoutingTablePeersRemoved,
+	TagKeys:     []tag.Key{KeyLocalPeerID, KeyInstanceID},
+	Aggregation: view.Count(),
 }}