expose metrics in Prometheus format at /metrics endpoint

* metrics can be enabled by setting `METRICS_ENABLED` env to `true`
* HTTP Basic authorization is supported
   - username is set using METRICS_USER env variable
   - password is set using METRICS_PASSWORD env variable

.vscode/settings.json

@@ -0,0 +1,8 @@
+{
+  "[markdown]": {
+    "editor.formatOnSave": false
+  },
+  "[yaml]": {
+    "editor.formatOnSave": false
+  }
+}

README.md

@@ -22,6 +22,7 @@ You have found the easiest way to install & manage WireGuard on any Linux host!
 * Statistics for which clients are connected.
 * Tx/Rx charts for each connected client.
 * Gravatar support.
+* Metrics in Prometheus format.
 
 ## Requirements
 
@@ -87,6 +88,9 @@ These options can be configured by setting environment variables using `-e KEY="
 | `WG_DEFAULT_ADDRESS` | `10.8.0.x` | `10.6.0.x` | Clients IP address range. |
 | `WG_DEFAULT_DNS` | `1.1.1.1` | `8.8.8.8, 8.8.4.4` | DNS server clients will use. |
 | `WG_ALLOWED_IPS` | `0.0.0.0/0, ::/0` | `192.168.15.0/24, 10.0.1.0/24` | Allowed IPs clients will use. |
+| `METRICS_ENABLED` | `false` | `true` | When set, metrics in Prometheus format will be exposed. |
+| `METRICS_USER` | - | `prometheus` | When set, HTTP Basic authorization with this user will be required when accessing metrics. |
+| `METRICS_PASSWORD` | - | `password` | When set, HTTP Basic authorization will with this password be required when accessing metrics. |
 
 > If you change `WG_PORT`, make sure to also change the exposed port.
 
@@ -100,4 +104,36 @@ docker rm wg-easy
 docker pull weejewel/wg-easy
 ```
 
-And then run the `docker run -d \ ...` command above again.
+And then run the `docker run -d \ ...` command above again.
+
+# Exposed metrics
+
+When metrics are enabled `wg-easy` will expose metrics in Prometheus format under `/metrics` path. HTTP Basic autorization is supported for metrics endpoint.
+
+Node process metrics specific to `wg-easy` are exported with `wg_easy_` prefix. WireGuard metrics are exported with `wireguard_` prefix.
+
+WireGuard metrics are inspired and compatible with metrics collected by [prometheus_wireguard_exporter](https://github.com/MindFlavor/prometheus_wireguard_exporter). Grafana dashboards created for [prometheus_wireguard_exporter](https://github.com/MindFlavor/prometheus_wireguard_exporter) works with metrics exposed by `wg-easy`.
+
+## Example WireGuard metrics
+
+```
+# HELP wireguard_sent_bytes_total Bytes sent to the peer
+# TYPE wireguard_sent_bytes_total counter
+wireguard_sent_bytes_total{interface="wg0",public_key="QpPNe62/SuCUSEkBTu3r2U0ihe2UrDspxUUgk195zmc=",allowed_ips="10.112.112.2/32",friendly_name="Test User 1",enabled="true"} 0
+wireguard_sent_bytes_total{interface="wg0",public_key="2AyHc7bRYJUJdx9UG87QmZDolj8xh6CORgP0PA28JT4=",allowed_ips="10.112.112.3/32",friendly_name="Test User 2",enabled="true"} 95788240
+
+# HELP wireguard_received_bytes_total Bytes received from the peer
+# TYPE wireguard_received_bytes_total counter
+wireguard_received_bytes_total{interface="wg0",public_key="QpPNe62/SuCUSEkBTu3r2U0ihe2UrDspxUUgk195zmc=",allowed_ips="10.112.112.2/32",friendly_name="Test User 1",enabled="true"} 0
+wireguard_received_bytes_total{interface="wg0",public_key="2AyHc7bRYJUJdx9UG87QmZDolj8xh6CORgP0PA28JT4=",allowed_ips="10.112.112.3/32",friendly_name="Test User 2",enabled="true"} 54389700
+
+# HELP wireguard_latest_handshake_seconds Seconds from the last handshake
+# TYPE wireguard_latest_handshake_seconds gauge
+wireguard_latest_handshake_seconds{interface="wg0",public_key="QpPNe62/SuCUSEkBTu3r2U0ihe2UrDspxUUgk195zmc=",allowed_ips="10.112.112.2/32",friendly_name="Test User 1",enabled="true"} 0
+wireguard_latest_handshake_seconds{interface="wg0",public_key="2AyHc7bRYJUJdx9UG87QmZDolj8xh6CORgP0PA28JT4=",allowed_ips="10.112.112.3/32",friendly_name="Test User 2",enabled="true"} 1633967910
+
+# HELP wireguard_persistent_keepalive_seconds Seconds between each persistent keepalive packet
+# TYPE wireguard_persistent_keepalive_seconds gauge
+wireguard_persistent_keepalive_seconds{interface="wg0",public_key="QpPNe62/SuCUSEkBTu3r2U0ihe2UrDspxUUgk195zmc=",allowed_ips="10.112.112.2/32",friendly_name="Test User 1",enabled="true"} 0
+wireguard_persistent_keepalive_seconds{interface="wg0",public_key="2AyHc7bRYJUJdx9UG87QmZDolj8xh6CORgP0PA28JT4=",allowed_ips="10.112.112.3/32",friendly_name="Test User 2",enabled="true"} 0
+```

docker-compose.dev.yml

@@ -1,9 +1,12 @@
-version: "3.8"
+version: '3.8'
 services:
   wg-easy:
     image: wg-easy
     command: npm run serve
     volumes:
       - ./src/:/app/
-    # environment: 
+    # environment:
     #   - PASSWORD=p
+    #   - METRICS_ENABLED=true
+    #   - METRICS_USER=u
+    #   - METRICS_PASSWORD=p

docker-compose.yml

@@ -1,4 +1,4 @@
-version: "3.8"
+version: '3.8'
 services:
   wg-easy:
     environment:
@@ -12,14 +12,17 @@ services:
       # - WG_DEFAULT_ADDRESS=10.8.0.x
       # - WG_DEFAULT_DNS=1.1.1.1
       # - WG_ALLOWED_IPS=192.168.15.0/24, 10.0.1.0/24
-      
+      # - METRICS_ENABLED=true
+      # - METRICS_USER=prometheus
+      # - METRICS_PASSWORD=password
+
     image: weejewel/wg-easy
     container_name: wg-easy
     volumes:
       - .:/etc/wireguard
     ports:
-      - "51820:51820/udp"
-      - "51821:51821/tcp"
+      - '51820:51820/udp'
+      - '51821:51821/tcp'
     restart: unless-stopped
     cap_add:
       - NET_ADMIN

src/config.js

@@ -14,3 +14,6 @@ module.exports.WG_DEFAULT_DNS = typeof process.env.WG_DEFAULT_DNS === 'string'
   ? process.env.WG_DEFAULT_DNS
   : '1.1.1.1';
 module.exports.WG_ALLOWED_IPS = process.env.WG_ALLOWED_IPS || '0.0.0.0/0, ::/0';
+module.exports.METRICS_ENABLED = process.env.METRICS_ENABLED === 'true' || false;
+module.exports.METRICS_USER = process.env.METRICS_USER;
+module.exports.METRICS_PASSWORD = process.env.METRICS_PASSWORD;

src/lib/Metrics.js

@@ -0,0 +1,71 @@
+'use strict';
+
+const client = require('prom-client');
+
+const { collectDefaultMetrics } = client;
+collectDefaultMetrics({ prefix: 'wg_easy_' });
+
+const sentBytesTotal = new client.Counter({
+  name: 'wireguard_sent_bytes_total',
+  help: 'Bytes sent to the peer',
+  labelNames: ['interface', 'public_key', 'allowed_ips', 'friendly_name', 'enabled'],
+});
+
+const reveivedBytesTotal = new client.Counter({
+  name: 'wireguard_received_bytes_total',
+  help: 'Bytes received from the peer',
+  labelNames: ['interface', 'public_key', 'allowed_ips', 'friendly_name', 'enabled'],
+});
+
+const latestHandshakeSeconds = new client.Gauge({
+  name: 'wireguard_latest_handshake_seconds',
+  help: 'Seconds from the last handshake',
+  labelNames: ['interface', 'public_key', 'allowed_ips', 'friendly_name', 'enabled'],
+});
+
+const persistentKeepaliveSeconds = new client.Gauge({
+  name: 'wireguard_persistent_keepalive_seconds',
+  help: 'Seconds between each persistent keepalive packet',
+  labelNames: ['interface', 'public_key', 'allowed_ips', 'friendly_name', 'enabled'],
+});
+
+module.exports = class Metrics {
+
+  async getMetrics(wgClients) {
+    if (!wgClients) {
+      return client.register.metrics();
+    }
+
+    for (const wgClient of wgClients) {
+      const labels = {
+        interface: wgClient.interface,
+        public_key: wgClient.publicKey,
+        allowed_ips: wgClient.allowedIPs,
+        friendly_name: wgClient.name,
+        enabled: wgClient.enabled,
+      };
+
+      sentBytesTotal.remove(labels);
+      sentBytesTotal.labels(labels).inc(wgClient.transferTx || 0);
+
+      reveivedBytesTotal.remove(labels);
+      reveivedBytesTotal.labels(labels).inc(wgClient.transferRx || 0);
+
+      if (!wgClient.latestHandshakeAt) {
+        latestHandshakeSeconds.labels(labels).set(0);
+      } else {
+        const seconds = Math.round(Date.parse(wgClient.latestHandshakeAt) / 1000.0);
+        latestHandshakeSeconds.labels(labels).set(seconds);
+      }
+
+      if (!wgClient.persistentKeepalive || wgClient.persistentKeepalive === 'off') {
+        persistentKeepaliveSeconds.labels(labels).set(0);
+      } else {
+        persistentKeepaliveSeconds.labels(labels).set(wgClient.persistentKeepalive);
+      }
+    }
+
+    return client.register.metrics();
+  }
+
+};

src/lib/Server.js

@@ -9,11 +9,15 @@ const debug = require('debug')('Server');
 const Util = require('./Util');
 const ServerError = require('./ServerError');
 const WireGuard = require('../services/WireGuard');
+const Metrics = require('../services/Metrics');
 
 const {
   PORT,
   RELEASE,
   PASSWORD,
+  METRICS_ENABLED,
+  METRICS_USER,
+  METRICS_PASSWORD,
 } = require('../config');
 
 module.exports = class Server {
@@ -23,6 +27,36 @@ module.exports = class Server {
     this.app = express()
       .disable('etag')
       .use('/', express.static(path.join(__dirname, '..', 'www')))
+
+      // Metrics
+      .get('/metrics', (Util.promisify(async (req, res) => {
+        if (!METRICS_ENABLED) {
+          throw new ServerError('Metrics Disabled', 400);
+        }
+
+        res.set('WWW-Authenticate', 'Basic realm="WireGuard Metrics"');
+
+        if (METRICS_USER || METRICS_PASSWORD) {
+          if (!req.headers['authorization']) {
+            throw new ServerError('Unauthorized', 401);
+          }
+
+          const [authScheme, authCredentials] = req.headers['authorization'].split(' ');
+          if (authScheme !== 'Basic' || !authCredentials) {
+            throw new ServerError('Unauthorized', 401);
+          }
+
+          const credentials = Buffer.from(`${METRICS_USER || ''}:${METRICS_PASSWORD || ''}`).toString('base64');
+          if (authCredentials !== credentials) {
+            throw new ServerError('Unauthorized', 401);
+          }
+        }
+
+        const metrics = await Metrics.getMetrics(await WireGuard.getClients());
+        res.header('Content-Type', 'text/plain');
+        res.send(metrics);
+      })))
+
       .use(express.json())
       .use(expressSession({
         secret: String(Math.random()),

src/lib/WireGuard.js

@@ -114,6 +114,7 @@ AllowedIPs = ${client.address}/32`;
     const config = await this.getConfig();
     const clients = Object.entries(config.clients).map(([clientId, client]) => ({
       id: clientId,
+      interface: 'wg0',
       name: client.name,
       enabled: client.enabled,
       address: client.address,

src/package-lock.json

@@ -342,6 +342,16 @@
       "resolved": "https://registry.npmjs.org/base64-js/-/base64-js-1.5.1.tgz",
       "integrity": "sha512-AKpaYlHn8t4SVbOHCy+b5+KKgvR4vrsD8vbvrbiQJps7fKDTkjkDry6ji0rUJjC0kzbNePLwzxq8iypo41qeWA=="
     },
+    "binary-extensions": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/binary-extensions/-/binary-extensions-2.2.0.tgz",
+      "integrity": "sha512-jDctJ/IVQbZoJykoeHbhXpOlNBqGNcwXJKJog42E5HDPUwQTSdjCHdihjj0DlnheQ7blbT6dHOafNAiS8ooQKA=="
+    },
+    "bintrees": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/bintrees/-/bintrees-1.0.1.tgz",
+      "integrity": "sha1-DmVcm5wkNeqraL9AJyJtK1WjRSQ="
+    },
     "body-parser": {
       "version": "1.19.0",
       "resolved": "https://registry.npmjs.org/body-parser/-/body-parser-1.19.0.tgz",
@@ -1955,6 +1965,14 @@
       "integrity": "sha512-7PiHtLll5LdnKIMw100I+8xJXR5gW2QwWYkT6iJva0bXitZKa/XMrSbdmg3r2Xnaidz9Qumd0VPaMrZlF9V9sA==",
       "dev": true
     },
+    "prom-client": {
+      "version": "14.0.0",
+      "resolved": "https://registry.npmjs.org/prom-client/-/prom-client-14.0.0.tgz",
+      "integrity": "sha512-etPa4SMO4j6qTn2uaSZy7+uahGK0kXUZwO7WhoDpTf3yZ837I3jqUDYmG6N0caxuU6cyqrg0xmOxh+yneczvyA==",
+      "requires": {
+        "tdigest": "^0.1.1"
+      }
+    },
     "proxy-addr": {
       "version": "2.0.6",
       "resolved": "https://registry.npmjs.org/proxy-addr/-/proxy-addr-2.0.6.tgz",
@@ -2362,6 +2380,19 @@
         }
       }
     },
+    "tdigest": {
+      "version": "0.1.1",
+      "resolved": "https://registry.npmjs.org/tdigest/-/tdigest-0.1.1.tgz",
+      "integrity": "sha1-Ljyyw56kSeVdHmzZEReszKRYgCE=",
+      "requires": {
+        "bintrees": "1.0.1"
+      }
+    },
+    "term-size": {
+      "version": "2.2.1",
+      "resolved": "https://registry.npmjs.org/term-size/-/term-size-2.2.1.tgz",
+      "integrity": "sha512-wK0Ri4fOGjv/XPy8SBHZChl8CM7uMc5VML7SqiQ0zG7+J5Vr+RMQDoHa2CNT6KHUnTGIXH34UDMkPzAUyapBZg=="
+    },
     "text-table": {
       "version": "0.2.0",
       "resolved": "https://registry.npmjs.org/text-table/-/text-table-0.2.0.tgz",

src/package.json

@@ -15,6 +15,8 @@
     "debug": "^4.3.1",
     "express": "^4.17.1",
     "express-session": "^1.17.1",
+    "nodemon": "^2.0.12",
+    "prom-client": "^14.0.0",
     "qrcode": "^1.4.4",
     "uuid": "^8.3.2"
   },
@@ -30,4 +32,4 @@
   "engines": {
     "node": "14"
   }
-}
+}

src/services/Metrics.js

@@ -0,0 +1,5 @@
+'use strict';
+
+const Metrics = require('../lib/Metrics');
+
+module.exports = new Metrics();