added devcontainer.

fix build error, deploy using docker-compose works,
misc changes
using global MQTT instead of local one to tap to already existin broker

src/auth.js

@@ -7,7 +7,7 @@ const util = require('util');
 var app = require('express')();
 
 var db = require('./db');
-var config = require('./setup_const');
+//var config = require('./setup_const');
 var passport = require('passport');
 var Strategy = require('passport-local').Strategy;
 var CookieStrategy = require('passport-cookie').Strategy;

src/mqtt.js

@@ -2,7 +2,10 @@
 var db = require("./db");
 const env = process.env.NODE_ENV || "development";
 console.log("ENV: %s", env);
-const config = require(__dirname + "/../config/config.json")[env];
+
+const path = require('path');
+const configPath = path.join(__dirname, '/../config/config.json');
+const config = require(configPath)[env];
 
 console.log("MQTT: Checking config sources: process.env.MQTT_HOST: %s", process.env.MQTT_HOST);
 console.log("MQTT: Checking config sources: process.env.MQTT_PORT_HTTP: %s", process.env.MQTT_PORT_HTTP);
@@ -169,6 +172,28 @@ mqtt_client.on("message", function (topic, message) {
       console.log("MQTT> unexpected json payload at /Water/stop:" + message);
     }
   }
+  if(topic === EspDeviceName + "/ping"){
+    try {     
+      console.log("MQTT> processing /ping message. Payload:" + context);
+      var data = context.replace(/^\{|\}$/g, '').split('|');
+      var ip = data[4].replace(/"/g, ''); 
+      console.log("got reporded garden controller IP: " + ip);
+      console.log("MQTT> /ping got us " + data.length + "data items");
+      config.gardenIP = ip;      
+      
+      
+      // Make a copy of config and change that
+let newConfig = Object.assign({}, config);
+newConfig.gardenIP = ip;
+
+// Write the new config back to the original file
+fs.writeFileSync(configPath, JSON.stringify(newConfig, null, 2));
+
+    } catch (e) {
+      console.log("MQTT> error at /ping: " + e);
+    }
+
+  }
 
   if (!handled) {
     console.log(topic + " > " + message);