client/daemon: add doublezero_connection_info Prometheus metric

CHANGELOG.md

@@ -17,6 +17,7 @@ All notable changes to this project will be documented in this file.
 - Telemetry
   - Embed LocationOffsets from parent DZDs in signed TWAMP replies so inbound probes carry geolocation context, and make signed TWAMP replies more like LocationOffsets to couple with a new double-probe system for inbound probing.
 - Client
+  - Add `doublezero_connection_info` Prometheus metric exposing connection metadata (user_type, network, current_device, metro, tunnel_name, tunnel_src, tunnel_dst) ([#3201](https://github.com/malbeclabs/doublezero/pull/3201))
   - Increase default onchain fetch timeout from 20s to 60s to improve resilience on high-latency RPC paths; add `-reconciler-fetch-timeout` flag to allow operators to override
   - Add prometheus metrics for onchain RPC fetches: fetch duration histogram, result counter (success/error with stale cache/error with no cache), and stale cache age gauge
   - Increase default route liveness probe interval (TxMin/RxMin) from 300ms to 1s and raise MaxTxCeil from 1s to 3s to preserve backoff headroom

client/doublezerod/internal/manager/http.go

@@ -68,6 +68,7 @@ func (n *NetlinkManager) ServeProvision(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
+	n.updateConnectionInfoMetric()
 	_, _ = w.Write([]byte(`{"status": "ok"}`))
 }
 
@@ -97,6 +98,7 @@ func (n *NetlinkManager) ServeRemove(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	n.updateConnectionInfoMetric()
 	_, _ = w.Write([]byte(`{"status": "ok"}`))
 }
 
@@ -167,6 +169,38 @@ func (n *NetlinkManager) ServeV2Status(w http.ResponseWriter, _ *http.Request) {
 	})
 }
 
+// updateConnectionInfoMetric resets and repopulates the doublezero_connection_info
+// gauge with current service metadata.
+func (n *NetlinkManager) updateConnectionInfoMetric() {
+	metricConnectionInfo.Reset()
+
+	statuses, err := n.Status()
+	if err != nil || len(statuses) == 0 {
+		return
+	}
+
+	enriched := n.enrichStatuses(statuses)
+	for _, svc := range enriched {
+		metricConnectionInfo.WithLabelValues(
+			svc.UserType.String(),
+			n.network,
+			svc.CurrentDevice,
+			svc.Metro,
+			svc.TunnelName,
+			ipString(svc.TunnelSrc),
+			ipString(svc.TunnelDst),
+		).Set(1)
+	}
+}
+
+// ipString returns the string representation of an IP, or empty string if nil.
+func ipString(ip net.IP) string {
+	if ip == nil {
+		return ""
+	}
+	return ip.String()
+}
+
 // latencyToleranceNS matches the CLI's LATENCY_TOLERANCE_NS (5ms).
 const latencyToleranceNS int64 = 5_000_000
 

client/doublezerod/internal/manager/manager.go

@@ -461,6 +461,7 @@ func (n *NetlinkManager) reconcilerTeardown() {
 	}
 	// Clear cached tunnel src so a fresh lookup is done on next enable.
 	n.tunnelSrcCache = make(map[string]net.IP)
+	metricConnectionInfo.Reset()
 }
 
 func (n *NetlinkManager) reconcile(ctx context.Context) {
@@ -535,6 +536,8 @@ func (n *NetlinkManager) reconcile(ctx context.Context) {
 	// Reconcile unicast and multicast services
 	n.reconcileService(wantUnicast, n.HasUnicastService(), serviceUnicast, api.UserTypeIBRL, devicesByPK, mcastGroupsByPK, allPrefixes, data.Config)
 	n.reconcileService(wantMulticast, n.HasMulticastService(), serviceMulticast, api.UserTypeMulticast, devicesByPK, mcastGroupsByPK, allPrefixes, data.Config)
+
+	n.updateConnectionInfoMetric()
 }
 
 func (n *NetlinkManager) reconcileService(

client/doublezerod/internal/manager/metrics.go

@@ -56,4 +56,12 @@ var (
 		},
 		[]string{labelServiceType},
 	)
+
+	metricConnectionInfo = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "doublezero_connection_info",
+			Help: "Connection metadata for active DoubleZero services",
+		},
+		[]string{"user_type", "network", "current_device", "metro", "tunnel_name", "tunnel_src", "tunnel_dst"},
+	)
 )

client/doublezerod/internal/manager/reconciler_test.go

@@ -18,6 +18,7 @@ import (
 	"github.com/malbeclabs/doublezero/client/doublezerod/internal/pim"
 	"github.com/malbeclabs/doublezero/client/doublezerod/internal/routing"
 	"github.com/malbeclabs/doublezero/smartcontract/sdk/go/serviceability"
+	"github.com/prometheus/client_golang/prometheus/testutil"
 )
 
 // --- test mocks ---
@@ -1263,6 +1264,67 @@ func TestServeV2Status_Enrichment(t *testing.T) {
 	}
 }
 
+func TestConnectionInfoMetric(t *testing.T) {
+	devicePK := [32]byte{1}
+	exchangePK := [32]byte{2}
+	clientIP := net.IPv4(1, 2, 3, 4).To4()
+
+	device := testDevice(devicePK, [4]uint8{5, 6, 7, 8}, [][5]uint8{{10, 0, 0, 0, 24}})
+	device.ExchangePubKey = exchangePK
+	device.Code = "dz1"
+	device.Status = serviceability.DeviceStatusActivated
+
+	user := testUser([4]uint8{1, 2, 3, 4}, devicePK, serviceability.UserTypeIBRL, serviceability.UserStatusActivated)
+
+	fetcher := &mockFetcher{
+		data: &serviceability.ProgramData{
+			Config:  testConfig(),
+			Devices: []serviceability.Device{device},
+			Users:   []serviceability.User{user},
+			Exchanges: []serviceability.Exchange{
+				{PubKey: exchangePK, Name: "Amsterdam"},
+			},
+		},
+	}
+
+	dir := t.TempDir()
+	n := newTestNLM(fetcher,
+		WithClientIP(clientIP),
+		WithPollInterval(time.Hour),
+		WithStateDir(dir),
+		WithEnabled(true),
+		WithNetwork("testnet"),
+	)
+
+	// Reset metric to avoid cross-test pollution from promauto global state.
+	metricConnectionInfo.Reset()
+
+	t.Run("populated_after_reconcile", func(t *testing.T) {
+		n.reconcile(context.Background())
+
+		count := testutil.CollectAndCount(metricConnectionInfo)
+		if count != 1 {
+			t.Fatalf("expected 1 metric series, got %d", count)
+		}
+
+		val := testutil.ToFloat64(metricConnectionInfo.WithLabelValues(
+			"IBRL", "testnet", "dz1", "Amsterdam", "doublezero0", "1.2.3.4", "5.6.7.8",
+		))
+		if val != 1 {
+			t.Fatalf("expected metric value 1, got %f", val)
+		}
+	})
+
+	t.Run("cleared_after_teardown", func(t *testing.T) {
+		n.reconcilerTeardown()
+
+		count := testutil.CollectAndCount(metricConnectionInfo)
+		if count != 0 {
+			t.Fatalf("expected 0 metric series after teardown, got %d", count)
+		}
+	})
+}
+
 func TestServeV2Status_NoFetcher(t *testing.T) {
 	dir := t.TempDir()
 	// Create NLM with a nil-data fetcher to verify enrichment handles missing data gracefully.