[MQTT] Try to improve error handling

server/model/monitor.js

@@ -351,7 +351,7 @@ class Monitor extends BeanModel {
                     }
                 } else if (this.type === "mqtt") {
                     try {
-                        bean.msg = await mqttAsync(this.url, this.mqttTopic, this.mqttSuccessMessage, {
+                        bean.msg = await mqttAsync(this.hostname, this.mqttTopic, this.mqttSuccessMessage, {
                             mqttPort: this.port,
                             mqttUsername: this.mqttUsername,
                             mqttPassword: this.mqttPassword,

server/util-server.js

@@ -12,7 +12,6 @@ const fs = require("fs");
 const nodeJsUtil = require("util");
 const mqtt = require("mqtt");
 
-
 // From ping-lite
 exports.WIN = /^win/.test(process.platform);
 exports.LIN = /^linux/.test(process.platform);
@@ -94,36 +93,46 @@ exports.pingAsync = function (hostname, ipv6 = false) {
 exports.mqttAsync = function (hostname, topic, okMessage, options = {}) {
     return new Promise((resolve, reject) => {
         const { port, username, password, interval = 20 } = options;
-        try {
-            // Adds MQTT protocol to the hostname if not already present
-            if (!/^(?:http|mqtt)s?:\/\//.test(hostname)) {
-                hostname = "mqtt://" + hostname;
-            }
-            let client = mqtt.connect(hostname, {
-                port,
-                username,
-                password
-            });
-            client.on("connect", () => {
-                client.subscribe(topic);
-            });
-            client.on("message", (messageTopic, message) => {
-                if (messageTopic == topic) {
-                    if (message.toString() === okMessage) {
-                        client.end();
-                        resolve(`Topic: ${messageTopic}; Message: ${message.toString()}`);
-                    } else {
-                        client.end();
-                        reject(new Error(`Error; Topic: ${messageTopic}; Message: ${message.toString()}`));
-                    }
-                }
-            });
-            setTimeout(() => {
-                client.end();
-            }, interval * 1000);
-        } catch (error) {
-            reject(new Error(error));
+
+        // Adds MQTT protocol to the hostname if not already present
+        if (!/^(?:http|mqtt)s?:\/\//.test(hostname)) {
+            hostname = "mqtt://" + hostname;
         }
+
+        debug("MQTT connecting");
+
+        let client = mqtt.connect(hostname, {
+            port,
+            username,
+            password
+        });
+
+        client.on("connect", () => {
+            debug("MQTT subscribe topic");
+            client.subscribe(topic);
+        });
+
+        client.on("error", (error) => {
+            client.end();
+            reject(error);
+        });
+
+        client.on("message", (messageTopic, message) => {
+            if (messageTopic == topic) {
+                if (message.toString() === okMessage) {
+                    client.end();
+                    resolve(`Topic: ${messageTopic}; Message: ${message.toString()}`);
+                } else {
+                    client.end();
+                    reject(new Error(`Error; Topic: ${messageTopic}; Message: ${message.toString()}`));
+                }
+            }
+        });
+
+        setTimeout(() => {
+            client.end();
+        }, interval * 1000);
+
     });
 };