feat: Tailscale ping monitor

server/monitor-types/tailscale-ping.js

@@ -0,0 +1,95 @@
+const { MonitorType } = require("./monitor-type");
+const { UP, log } = require("../../src/util");
+const exec = require("child_process").exec;
+
+/**
+ * A TailscalePing class extends the MonitorType.
+ * It runs Tailscale ping to monitor the status of a specific node.
+ */
+class TailscalePing extends MonitorType {
+
+    name = "tailscale-ping";
+
+    /**
+     * Checks the ping status of the URL associated with the monitor.
+     * It then parses the Tailscale ping command output to update the heatrbeat.
+     *
+     * @param {Object} monitor - The monitor object associated with the check.
+     * @param {Object} heartbeat - The heartbeat object to update.
+     * @throws Will throw an error if checking Tailscale ping encounters any error
+     */
+    async check(monitor, heartbeat) {
+        try {
+            let tailscaleOutput = await this.runTailscalePing(monitor.hostname, monitor.interval);
+            this.parseTailscaleOutput(tailscaleOutput, heartbeat);
+        } catch (err) {
+            log.debug("Tailscale", err);
+            // trigger log function somewhere to display a notification or alert to the user (but how?)
+            throw new Error(`Error checking Tailscale ping: ${err}`);
+        }
+    }
+
+    /**
+     * Runs the Tailscale ping command to the given URL.
+     *
+     * @param {string} hostname - The hostname to ping.
+     * @returns {Promise<string>} - A Promise that resolves to the output of the Tailscale ping command
+     * @throws Will throw an error if the command execution encounters any error.
+     */
+    async runTailscalePing(hostname, interval) {
+        let cmd = `tailscale ping ${hostname}`;
+
+        log.debug("Tailscale", cmd);
+
+        return new Promise((resolve, reject) => {
+            let timeout = interval * 1000 * 0.8;
+            exec(cmd, { timeout: timeout }, (error, stdout, stderr) => {
+                // we may need to handle more cases if tailscale reports an error that isn't necessarily an error (such as not-logged in or DERP health-related issues)
+                if (error) {
+                    reject(`Execution error: ${error.message}`);
+                    return;
+                }
+                if (stderr) {
+                    reject(`Error in output: ${stderr}`);
+                    return;
+                }
+
+                resolve(stdout);
+            });
+        });
+    }
+
+    /**
+     * Parses the output of the Tailscale ping command to update the heartbeat.
+     *
+     * @param {string} tailscaleOutput - The output of the Tailscale ping command.
+     * @param {Object} heartbeat - The heartbeat object to update.
+     * @throws Will throw an eror if the output contains any unexpected string.
+     */
+    parseTailscaleOutput(tailscaleOutput, heartbeat) {
+        let lines = tailscaleOutput.split("\n");
+
+        for (let line of lines) {
+            if (line.includes("pong from")) {
+                heartbeat.status = UP;
+                let time = line.split(" in ")[1].split(" ")[0];
+                heartbeat.ping = parseInt(time);
+                heartbeat.msg = line;
+                break;
+            } else if (line.includes("timed out")) {
+                throw new Error(`Ping timed out: "${line}"`);
+                // Immediately throws upon "timed out" message, the server is expected to re-call the check function
+            } else if (line.includes("no matching peer")) {
+                throw new Error(`Nonexistant or inaccessible due to ACLs: "${line}"`);
+            } else if (line.includes("is local Tailscale IP")) {
+                throw new Error(`Tailscale only works if used on other machines: "${line}"`);
+            } else if (line !== "") {
+                throw new Error(`Unexpected output: "${line}"`);
+            }
+        }
+    }
+}
+
+module.exports = {
+    TailscalePing,
+};

server/uptime-kuma-server.js

@@ -99,6 +99,7 @@ class UptimeKumaServer {
 
         // Set Monitor Types
         UptimeKumaServer.monitorTypeList["real-browser"] = new RealBrowserMonitorType();
+        UptimeKumaServer.monitorTypeList["tailscale-ping"] = new TailscalePing();
 
         this.io = new Server(this.httpServer);
     }
@@ -345,3 +346,4 @@ module.exports = {
 
 // Must be at the end to avoid circular dependencies
 const { RealBrowserMonitorType } = require("./monitor-types/real-browser-monitor-type");
+const { TailscalePing } = require("./monitor-types/tailscale-ping");

src/lang/en.json

@@ -364,6 +364,7 @@
     "deleteDockerHostMsg": "Are you sure want to delete this docker host for all monitors?",
     "socket": "Socket",
     "tcp": "TCP / HTTP",
+    "tailscalePingWarning": "In order to use the Tailscale Ping monitor, you need to install Uptime Kuma without Docker and also install Tailscale client on your server.",
     "Docker Container": "Docker Container",
     "Container Name / ID": "Container Name / ID",
     "Docker Host": "Docker Host",

src/pages/EditMonitor.vue

@@ -82,10 +82,17 @@
                                         <option value="redis">
                                             Redis
                                         </option>
+                                        <option value="tailscale-ping">
+                                            Tailscale Ping
+                                        </option>
                                     </optgroup>
                                 </select>
                             </div>
 
+                            <div v-if="monitor.type === 'tailscale-ping'" class="alert alert-warning" role="alert">
+                                {{ $t("tailscalePingWarning") }}
+                            </div>
+
                             <!-- Friendly Name -->
                             <div class="my-3">
                                 <label for="name" class="form-label">{{ $t("Friendly Name") }}</label>
@@ -221,8 +228,8 @@
                             </template>
 
                             <!-- Hostname -->
-                            <!-- TCP Port / Ping / DNS / Steam / MQTT / Radius only -->
-                            <div v-if="monitor.type === 'port' || monitor.type === 'ping' || monitor.type === 'dns' || monitor.type === 'steam' || monitor.type === 'gamedig' ||monitor.type === 'mqtt' || monitor.type === 'radius'" class="my-3">
+                            <!-- TCP Port / Ping / DNS / Steam / MQTT / Radius / Tailscale Ping only -->
+                            <div v-if="monitor.type === 'port' || monitor.type === 'ping' || monitor.type === 'dns' || monitor.type === 'steam' || monitor.type === 'gamedig' ||monitor.type === 'mqtt' || monitor.type === 'radius' || monitor.type === 'tailscale-ping'" class="my-3">
                                 <label for="hostname" class="form-label">{{ $t("Hostname") }}</label>
                                 <input id="hostname" v-model="monitor.hostname" type="text" class="form-control" :pattern="`${monitor.type === 'mqtt' ? mqttIpOrHostnameRegexPattern : ipOrHostnameRegexPattern}`" required>
                             </div>