Expose network size estimation metric

lookup.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/libp2p/go-libp2p-kad-dht/internal"
+	"github.com/libp2p/go-libp2p-kad-dht/metrics"
 	"github.com/libp2p/go-libp2p-kad-dht/qpeerset"
 	kb "github.com/libp2p/go-libp2p-kbucket"
 	"github.com/libp2p/go-libp2p/core/peer"
@@ -44,6 +45,10 @@ func (dht *IpfsDHT) GetClosestPeers(ctx context.Context, key string) ([]peer.ID,
 		logger.Warnf("network size estimator track peers: %s", err)
 	}
 
+	if ns, err := dht.nsEstimator.NetworkSize(); err == nil {
+		metrics.NetworkSize.M(int64(ns))
+	}
+
 	// refresh the cpl for this key as the query was successful
 	dht.routingTable.ResetCplRefreshedAtForID(kb.ConvertKey(key), time.Now())
 

lookup_optim.go

@@ -8,6 +8,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/libp2p/go-libp2p-kad-dht/metrics"
 	"github.com/libp2p/go-libp2p-kad-dht/netsize"
 	"github.com/libp2p/go-libp2p-kad-dht/qpeerset"
 	kb "github.com/libp2p/go-libp2p-kbucket"
@@ -172,6 +173,10 @@ func (dht *IpfsDHT) optimisticProvide(outerCtx context.Context, keyMH multihash.
 		logger.Warnf("network size estimator track peers: %s", err)
 	}
 
+	if ns, err := dht.nsEstimator.NetworkSize(); err == nil {
+		metrics.NetworkSize.M(int64(ns))
+	}
+
 	// refresh the cpl for this key as the query was successful
 	dht.routingTable.ResetCplRefreshedAtForID(kb.ConvertKey(key), time.Now())
 

metrics/metrics.go

@@ -39,6 +39,7 @@ var (
 	SentRequests           = stats.Int64("libp2p.io/dht/kad/sent_requests", "Total number of requests sent per RPC", stats.UnitDimensionless)
 	SentRequestErrors      = stats.Int64("libp2p.io/dht/kad/sent_request_errors", "Total number of errors for requests sent per RPC", stats.UnitDimensionless)
 	SentBytes              = stats.Int64("libp2p.io/dht/kad/sent_bytes", "Total sent bytes per RPC", stats.UnitBytes)
+	NetworkSize            = stats.Int64("libp2p.io/dht/kad/network_size", "Network size estimation", stats.UnitDimensionless)
 )
 
 // Views
@@ -93,6 +94,11 @@ var (
 		TagKeys:     []tag.Key{KeyMessageType, KeyPeerID, KeyInstanceID},
 		Aggregation: defaultBytesDistribution,
 	}
+	NetworkSizeView = &view.View{
+		Measure:     NetworkSize,
+		TagKeys:     []tag.Key{KeyPeerID, KeyInstanceID},
+		Aggregation: view.Count(),
+	}
 )
 
 // DefaultViews with all views in it.
@@ -107,4 +113,5 @@ var DefaultViews = []*view.View{
 	SentRequestsView,
 	SentRequestErrorsView,
 	SentBytesView,
+	NetworkSizeView,
 }