Clarify VPN and Direct traffic metrics in Grafana dashboard

src/server/prometheusMetrics.ts

@@ -4,6 +4,7 @@ const COUNTER_PATTERN = /^\d+$/;
 const SIGNED_DECIMAL_PATTERN = /^-?\d+$/;
 const COLLECTOR_MODES = new Set(['snapshot', 'shadow', 'native']);
 const COLLECTOR_WRITERS = new Set(['snapshot', 'native']);
+const APPLIED_POLICY_VALUES: Readonly<Record<string, string>> = Object.freeze({ direct: '0', vpn: '1' });
 const COLLECTOR_STATES = new Set([
   'connecting', 'live', 'degraded', 'stale', 'stopped', 'incompatible', 'disabled',
 ]);
@@ -93,6 +94,20 @@ export function renderPrometheusMetrics(value: unknown) {
         ip: device.ip || '',
       }, '1');
     }
+
+    lines.push(
+      '# HELP harbor_device_applied_policy Current applied device policy: 0 Direct, 1 VPN.',
+      '# TYPE harbor_device_applied_policy gauge',
+    );
+    for (const device of devices) {
+      const appliedPolicy = String(device.appliedPolicy || '');
+      if (!Object.hasOwn(APPLIED_POLICY_VALUES, appliedPolicy)) {
+        throw new Error('Invalid applied device policy');
+      }
+      metric(lines, 'harbor_device_applied_policy', {
+        device_id: device.id,
+      }, APPLIED_POLICY_VALUES[appliedPolicy]);
+    }
   }
 
   const deviceTraffic = devices.flatMap((device) => [