feat: add network topology metrics (closes #931) (#981)

Bumps github.com/unpoller/unifi/v5 to v5.23.0 which adds
GetTopology() fetching vertices (devices/clients) and edges
(wired/wireless connections) from /proxy/network/v2/api/site/{site}/topology.

Changes across the stack:
- poller.Metrics: add Topologies []any field + AppendMetrics support
- inputunifi: collect topology per-site (non-fatal on older controllers),
  pass through augmentMetrics with site name override support
- promunifi: new topology.go with summary, connection-type, link-quality,
  and band-distribution gauges
- influxunifi: new topology.go with topology_summary and topology_edge
  measurements
- datadogunifi: new topology.go with equivalent Datadog gauges
- otelunifi: new topology.go with OpenTelemetry gauge observations

Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

pkg/datadogunifi/datadog.go

@@ -325,6 +325,10 @@ func (u *DatadogUnifi) loopPoints(r report) {
 	for _, p := range m.FirewallPolicies {
 		u.switchExport(r, p)
 	}
+
+	for _, t := range m.Topologies {
+		u.switchExport(r, t)
+	}
 }
 
 func (u *DatadogUnifi) switchExport(r report, v any) { //nolint:cyclop
@@ -367,6 +371,8 @@ func (u *DatadogUnifi) switchExport(r report, v any) { //nolint:cyclop
 		u.batchWAN(r, v)
 	case *unifi.FirewallPolicy:
 		u.batchFirewallPolicy(r, v)
+	case *unifi.Topology:
+		u.batchTopology(r, v)
 	default:
 		if u.Collector != nil && u.Collector.Poller().LogUnknownTypes {
 			u.LogDebugf("unknown export type: %T", v)

pkg/datadogunifi/topology.go

@@ -0,0 +1,101 @@
+package datadogunifi
+
+import (
+	"github.com/unpoller/unifi/v5"
+)
+
+// batchTopology generates topology datapoints for Datadog.
+func (u *DatadogUnifi) batchTopology(r report, t *unifi.Topology) {
+	if t == nil {
+		return
+	}
+
+	metricName := metricNamespace("topology")
+
+	siteTags := []string{
+		tag("site_name", t.SiteName),
+		tag("source", t.SourceName),
+	}
+
+	var (
+		devices    int
+		clients    int
+		wired      int
+		wireless   int
+		fullDuplex int
+	)
+
+	unknownSwitch := 0.0
+	if t.HasUnknownSwitch {
+		unknownSwitch = 1.0
+	}
+
+	for i := range t.Vertices {
+		switch t.Vertices[i].Type {
+		case "DEVICE":
+			devices++
+		case "CLIENT":
+			clients++
+		}
+	}
+
+	bandCounts := make(map[string]int)
+
+	for i := range t.Edges {
+		e := &t.Edges[i]
+
+		edgeTags := []string{
+			tag("uplink_mac", e.UplinkMac),
+			tag("downlink_mac", e.DownlinkMac),
+			tag("link_type", e.Type),
+			tag("site_name", t.SiteName),
+			tag("source", t.SourceName),
+		}
+
+		switch e.Type {
+		case "WIRED":
+			wired++
+
+			if e.Duplex == "FULL_DUPLEX" {
+				fullDuplex++
+			}
+
+			_ = r.reportGauge(metricName("link_rate_mbps"), e.RateMbps.Val, edgeTags)
+
+		case "WIRELESS":
+			wireless++
+
+			if e.RadioBand != "" {
+				bandCounts[e.RadioBand]++
+			}
+
+			if e.ExperienceScore.Val > 0 {
+				_ = r.reportGauge(metricName("link_experience_score"), e.ExperienceScore.Val, edgeTags)
+			}
+		}
+	}
+
+	summary := map[string]float64{
+		"vertices_total":       float64(len(t.Vertices)),
+		"edges_total":          float64(len(t.Edges)),
+		"devices_total":        float64(devices),
+		"clients_total":        float64(clients),
+		"connections_wired":    float64(wired),
+		"connections_wireless": float64(wireless),
+		"wired_full_duplex":    float64(fullDuplex),
+		"has_unknown_switch":   unknownSwitch,
+	}
+
+	for name, value := range summary {
+		_ = r.reportGauge(metricName(name), value, siteTags)
+	}
+
+	for band, count := range bandCounts {
+		bandTags := []string{
+			tag("band", band),
+			tag("site_name", t.SiteName),
+			tag("source", t.SourceName),
+		}
+		_ = r.reportGauge(metricName("connections_by_band"), float64(count), bandTags)
+	}
+}