Added initial working "Health Check" feature

server/model/monitor.js

@@ -7,6 +7,7 @@ const { log, UP, DOWN, PENDING, MAINTENANCE, flipStatus, MAX_INTERVAL_SECOND, MI
 const { tcping, ping, checkCertificate, checkStatusCode, getTotalClientInRoom, setting, mssqlQuery, postgresQuery, mysqlQuery, setSetting, httpNtlm, radius, grpcQuery,
     redisPingAsync, kafkaProducerAsync, getOidcTokenClientCredentials, rootCertificatesFingerprints, axiosAbortSignal
 } = require("../util-server");
+const { Settings } = require("../settings");
 const { R } = require("redbean-node");
 const { BeanModel } = require("redbean-node/dist/bean-model");
 const { Notification } = require("../notification");
@@ -345,6 +346,16 @@ class Monitor extends BeanModel {
                 }
             }
 
+            /**
+             * If the monitor designated to represent healthy connectivity is down,
+             * then we can just stop here.
+             */
+            const systemIsHealthy = await this.systemIsHealthy();
+            if (systemIsHealthy === false) {
+                log.warn("monitor", "Health check monitor is down, monitoring paused!");
+                return;
+            }
+
             // Expose here for prometheus update
             // undefined if not https
             let tlsInfo = undefined;
@@ -1737,6 +1748,42 @@ class Monitor extends BeanModel {
             await this.checkCertExpiryNotifications(tlsInfo);
         }
     }
+
+    /**
+     * Checks if the monitor selected for the health check is down.
+     * @returns {Promise<boolean>} If true, the system is healthy.
+     */
+    async systemIsHealthy() {
+        let healthCheckMonitorId = await Settings.get("healthCheckMonitorId");
+
+        // User hasn't made a selection yet, save in the database as null
+        if (healthCheckMonitorId === undefined) {
+            await setSetting("healthCheckMonitorId", null);
+            healthCheckMonitorId = null;
+        }
+
+        // No health check monitor is specified, nothing to do!
+        if (healthCheckMonitorId === null) {
+            return true;
+        }
+
+        // We still need to check the health check monitor
+        if (healthCheckMonitorId === this.id) {
+            return true;
+        }
+
+        const healthCheckMonitor = await R.findOne("heartbeat", " monitor_id = ? ORDER BY time DESC", [
+            healthCheckMonitorId,
+        ]);
+
+        if (healthCheckMonitor) {
+            return healthCheckMonitor.id === UP;
+        }
+
+        // Default to indicative of being healthy, this shouldn't happen
+        // Better to be safe if we can't find the selector monitor, it may have been deleted
+        return true;
+    }
 }
 
 module.exports = Monitor;

src/components/settings/Notifications.vue

@@ -53,6 +53,29 @@
             </div>
         </div>
 
+        <div v-if="settingsLoaded" class="my-4 pt-4">
+            <h5 class="my-4 settings-subheading">{{ $t("Heath Check") }}</h5>
+            <p>{{ $t("HealthCheckDescription") }}</p>
+
+            <div class="my-4">
+                <label for="timezone" class="form-label">
+                    {{ $t("Monitor") }}
+                </label>
+                <select id="timezone" v-model="settings.healthCheckMonitorId" class="form-select">
+                    <option :value="null">
+                        {{ $t("Select") }}
+                    </option>
+                    <option
+                        v-for="(monitor, index) in $root.monitorList"
+                        :key="index"
+                        :value="monitor.id"
+                    >
+                        {{ monitor.name }}
+                    </option>
+                </select>
+            </div>
+        </div>
+
         <div class="my-4 pt-4">
             <h5 class="my-4 settings-subheading">{{ $t("settingsCertificateExpiry") }}</h5>
             <p>{{ $t("certificationExpiryDescription") }}</p>
@@ -184,7 +207,7 @@ export default {
                     this.toastErrorTimeoutSecs = parsedTimeout > 0 ? parsedTimeout / 1000 : parsedTimeout;
                 }
             }
-        },
+        }
     },
 };
 </script>

src/lang/en.json

@@ -1067,5 +1067,7 @@
     "YZJ Robot Token": "YZJ Robot token",
     "Plain Text": "Plain Text",
     "Message Template": "Message Template",
-    "Template Format": "Template Format"
+    "Template Format": "Template Format",
+    "Heath Check": "Heath Check",
+    "HealthCheckDescription": "If the selected monitor is offline, all notifications will be paused and downtime ignored. Ideal for monitoring connectivity to the internet."
 }

src/pages/Settings.vue

@@ -183,6 +183,10 @@ export default {
                     this.settings.trustProxy = false;
                 }
 
+                if (this.settings.healthCheckMonitorId === undefined) {
+                    this.settings.healthCheckMonitorId = null;
+                }
+
                 this.settingsLoaded = true;
             });
         },