feat: export site_to_site_enabled VPN metric (#926) (#976)

Add the site_to_site_enabled FlexBool field from the vpn subsystem
health entry to both InfluxDB and Prometheus outputs. The field was
present in the unifi.Health struct but never exported.

- influxunifi: add site_to_site_enabled to subsystems fields map
- promunifi: add SiteToSiteEnabled gauge descriptor and emit it in
  the vpn case of exportSite
- Update integration_test_expectations.yaml to include the new field

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

pkg/influxunifi/integration_test_expectations.yaml

@@ -211,6 +211,7 @@ points:
       rx_bytes-r: int
       speedtest_lastrun: float
       speedtest_ping: float
+      site_to_site_enabled: bool
       tx_bytes-r: int
       uptime: int
       wan_ip: string

pkg/influxunifi/site.go

@@ -57,6 +57,7 @@ func (u *InfluxUnifi) batchSite(r report, s *unifi.Site) {
 			"remote_user_tx_bytes":     h.RemoteUserTxBytes.Val,
 			"remote_user_rx_packets":   h.RemoteUserRxPackets.Val,
 			"remote_user_tx_packets":   h.RemoteUserTxPackets.Val,
+			"site_to_site_enabled":     h.SiteToSiteEnabled.Val,
 			"num_new_alarms":           s.NumNewAlarms.Val,
 		}
 

pkg/promunifi/site.go

@@ -31,6 +31,7 @@ type site struct {
 	RemoteUserTxBytes     *prometheus.Desc
 	RemoteUserRxPackets   *prometheus.Desc
 	RemoteUserTxPackets   *prometheus.Desc
+	SiteToSiteEnabled     *prometheus.Desc
 	DPITxPackets          *prometheus.Desc
 	DPIRxPackets          *prometheus.Desc
 	DPITxBytes            *prometheus.Desc
@@ -68,6 +69,7 @@ func descSite(ns string) *site {
 		RemoteUserTxBytes:     nd(ns+"remote_user_transmit_bytes_total", "Remote Users Transmit Bytes", labels, nil),
 		RemoteUserRxPackets:   nd(ns+"remote_user_receive_packets_total", "Remote Users Receive Packets", labels, nil),
 		RemoteUserTxPackets:   nd(ns+"remote_user_transmit_packets_total", "Remote Users Transmit Packets", labels, nil),
+		SiteToSiteEnabled:     nd(ns+"site_to_site_enabled", "Site-to-site VPN enabled (1/0)", labels, nil),
 		DPITxPackets:          nd(ns+"dpi_transmit_packets", "Site DPI Transmit Packets", labelDPI, nil),
 		DPIRxPackets:          nd(ns+"dpi_receive_packets", "Site DPI Receive Packets", labelDPI, nil),
 		DPITxBytes:            nd(ns+"dpi_transmit_bytes", "Site DPI Transmit Bytes", labelDPI, nil),
@@ -160,6 +162,7 @@ func (u *promUnifi) exportSite(r report, s *unifi.Site) {
 				{u.Site.RemoteUserTxBytes, counter, h.RemoteUserTxBytes, labels},
 				{u.Site.RemoteUserRxPackets, counter, h.RemoteUserRxPackets, labels},
 				{u.Site.RemoteUserTxPackets, counter, h.RemoteUserTxPackets, labels},
+				{u.Site.SiteToSiteEnabled, gauge, h.SiteToSiteEnabled.Val, labels},
 			})
 		}
 	}