Add Prometheus metrics

[Feat]: Simple Stats API #1285

src/lib/WireGuard.js

@@ -158,6 +158,7 @@ ${client.preSharedKey ? `PresharedKey = ${client.preSharedKey}\n` : ''
       latestHandshakeAt: null,
       transferRx: null,
       transferTx: null,
+      endpoint: null,
     }));
 
     // Loop WireGuard status
@@ -186,6 +187,7 @@ ${client.preSharedKey ? `PresharedKey = ${client.preSharedKey}\n` : ''
         client.latestHandshakeAt = latestHandshakeAt === '0'
           ? null
           : new Date(Number(`${latestHandshakeAt}000`));
+        client.endpoint = endpoint === '(none)' ? null : endpoint;
         client.transferRx = Number(transferRx);
         client.transferTx = Number(transferTx);
         client.persistentKeepalive = persistentKeepalive;
@@ -398,4 +400,75 @@ Endpoint = ${WG_HOST}:${WG_CONFIG_PORT}`;
     }
   }
 
+  async getMetrics() {
+    const clients = await this.getClients();
+    let wireguardPeerCount = 0;
+    let wireguardEnabledPeersCount = 0;
+    let wireguardConnectedPeersCount = 0;
+    let wireguardSentBytes = '';
+    let wireguardReceivedBytes = '';
+    let wireguardLatestHandshakeSeconds = '';
+    for (const client of Object.values(clients)) {
+      wireguardPeerCount++;
+      if (client.enabled === true) {
+        wireguardEnabledPeersCount++;
+      }
+      if (client.endpoint !== null) {
+        wireguardConnectedPeersCount++;
+      }
+      wireguardSentBytes += `wireguard_sent_bytes{interface="wg0",enabled="${client.enabled}",address="${client.address}",name="${client.name}"} ${Number(client.transferTx)}\n`;
+      wireguardReceivedBytes += `wireguard_received_bytes{interface="wg0",enabled="${client.enabled}",address="${client.address}",name="${client.name}"} ${Number(client.transferRx)}\n`;
+      wireguardLatestHandshakeSeconds += `wireguard_latest_handshake_seconds{interface="wg0",enabled="${client.enabled}",address="${client.address}",name="${client.name}"} ${client.latestHandshakeAt ? (new Date().getTime() - new Date(client.latestHandshakeAt).getTime()) / 1000 : 0}\n`;
+    }
+
+    let returnText = '# HELP wg-easy and wireguard metrics\n';
+
+    returnText += '\n# HELP wireguard_configured_peers\n';
+    returnText += '# TYPE wireguard_configured_peers gauge\n';
+    returnText += `wireguard_configured_peers{interface="wg0"} ${Number(wireguardPeerCount)}\n`;
+
+    returnText += '\n# HELP wireguard_enabled_peers\n';
+    returnText += '# TYPE wireguard_enabled_peers gauge\n';
+    returnText += `wireguard_enabled_peers{interface="wg0"} ${Number(wireguardEnabledPeersCount)}\n`;
+
+    returnText += '\n# HELP wireguard_connected_peers\n';
+    returnText += '# TYPE wireguard_connected_peers gauge\n';
+    returnText += `wireguard_connected_peers{interface="wg0"} ${Number(wireguardConnectedPeersCount)}\n`;
+
+    returnText += '\n# HELP wireguard_sent_bytes Bytes sent to the peer\n';
+    returnText += '# TYPE wireguard_sent_bytes counter\n';
+    returnText += `${wireguardSentBytes}`;
+
+    returnText += '\n# HELP wireguard_received_bytes Bytes received from the peer\n';
+    returnText += '# TYPE wireguard_received_bytes counter\n';
+    returnText += `${wireguardReceivedBytes}`;
+
+    returnText += '\n# HELP wireguard_latest_handshake_seconds UNIX timestamp seconds of the last handshake\n';
+    returnText += '# TYPE wireguard_latest_handshake_seconds gauge\n';
+    returnText += `${wireguardLatestHandshakeSeconds}`;
+
+    return returnText;
+  }
+
+  async getMetricsJSON() {
+    const clients = await this.getClients();
+    let wireguardPeerCount = 0;
+    let wireguardEnabledPeersCount = 0;
+    let wireguardConnectedPeersCount = 0;
+    for (const client of Object.values(clients)) {
+      wireguardPeerCount++;
+      if (client.enabled === true) {
+        wireguardEnabledPeersCount++;
+      }
+      if (client.endpoint !== null) {
+        wireguardConnectedPeersCount++;
+      }
+    }
+    return {
+      wireguard_configured_peers: Number(wireguardPeerCount),
+      wireguard_enabled_peers: Number(wireguardEnabledPeersCount),
+      wireguard_connected_peers: Number(wireguardConnectedPeersCount),
+    };
+  }
+
 };