Enabled MQTT subscribe callback to switch OLED on/off

Author: mthorley

include/MqttManager.h

@@ -0,0 +1,53 @@
+#include "RackTempController.h"
+#include <Ethernet.h>
+#include <ArduinoMqttClient.h>
+#include <Print.h>
+
+/**
+ * Wrapper class for MQTT and Logging framework
+ */ 
+class MqttManager : public Print {
+
+public:
+    MqttManager(MqttClient* p_mqttClient, const char* clientID, const char* serverIP, const uint16_t port) :
+        _p_mqttClient(p_mqttClient),
+        _clientID(clientID),
+        _serverIP(serverIP),
+        _port(port) {};
+
+    int initialise();
+
+    void publish(RackState_t& rs);
+
+    void poll();
+
+    /**
+     * From Print.h
+     */
+    size_t write(uint8_t c);
+    
+private:
+    void sendMessage(const String& topic, const String& msg);
+
+    MqttClient* _p_mqttClient;
+
+    const String   _clientID;   // client identifier
+    const String   _serverIP;   // mqtt server IP endpoint
+    const uint16_t _port;       // mqtt server port
+    String         _buf;        // log buffer    
+
+    const String topicTempRackTop  = "/device/temp/rack/top";
+    const String topicTempRackBase = "/device/temp/rack/base";
+    const String topicTempRackAve  = "/device/temp/rack/average";
+    
+    const String topicFanTopLeft   = "/device/rack/fan/topleft";
+    const String topicFanTopRight  = "/device/rack/fan/topright";
+    const String topicFanBaseLeft  = "/device/rack/fan/baseleft";
+    const String topicFanBaseRight = "/device/rack/fan/baseright";
+
+    const String topicConfig      = "/device/rack/config";  //display on/off subscriber topic 
+
+    const String topicRackLog     = "/device/rack/log";
+    const String subtopicFanError = "/error";
+    const String subtopicFanRPM   = "/rpm";
+};

src/MqttManager.cpp

@@ -0,0 +1,78 @@
+#include "MqttManager.h"
+#include <ArduinoLog.h>
+
+extern void onMqttMessage(int messageSize);
+
+int MqttManager::initialise()
+{
+    if (!_p_mqttClient->connect(_serverIP.c_str(), _port)) {
+        Log.error(F("Mqtt connection failed - error code %d"), _p_mqttClient->connectError());
+        return _p_mqttClient->connectError();
+    }
+    _p_mqttClient->setId(_clientID);
+
+    // set message handler for callback
+    _p_mqttClient->onMessage(::onMqttMessage);
+
+    // subscribe to config topic
+    _p_mqttClient->subscribe(topicConfig);
+
+    return 0;
+}
+
+void MqttManager::publish(RackState_t& rs) {
+    
+    if (!_p_mqttClient->connected()) {
+        Log.error(F("Mqtt connection lost ... attempting reconnection"));
+        initialise();
+    }
+
+    Log.notice(F("Publishing temperature events"));
+    sendMessage(topicTempRackTop, String(rs.thermos["topRack"].tempCelsuis));
+    sendMessage(topicTempRackBase, String(rs.thermos["baseRack"].tempCelsuis));
+    sendMessage(topicTempRackAve, String(rs.aveTempCelsius));
+    
+    //Log.notice(F("Publishing fan events"));
+    /*
+    sendMessage(topicFanBaseLeft + subtopicFanRPM, String(rs.fanTopLeft.rpm));
+    sendMessage(topicFanTopRight + subtopicFanRPM, String(rs.fanTopRight.rpm));
+    sendMessage(topicFanBaseLeft + subtopicFanRPM, String(rs.fanBaseLeft.rpm));
+    sendMessage(topicFanTopRight + subtopicFanRPM, String(rs.fanBaseRight.rpm));
+    */
+
+    // if (rs.hasFanError()) {  
+    //     for each fan in error
+    //        sendMessage(topicRackFanError, rs.fanid)
+    //}
+    
+}
+
+void MqttManager::poll() {
+    _p_mqttClient->poll();
+}
+
+void MqttManager::sendMessage(const String& topic, const String& msg)
+{
+    _p_mqttClient->beginMessage(topic);
+    _p_mqttClient->print(msg);
+    if (!_p_mqttClient->endMessage())
+        Log.error(F("Failed to send message to topic %s"), topic.c_str());
+}
+
+/**
+ * From Print.h
+ * Enables writing all log events to the topicRackLog
+ */
+size_t MqttManager::write(uint8_t c) {
+    Serial.print(char(c));
+    _buf += (char)c;
+    if (c == '\n') {
+        if (_p_mqttClient->connected()) {
+            _p_mqttClient->beginMessage(topicRackLog);
+            _p_mqttClient->print(_buf);
+            _p_mqttClient->endMessage();
+        }
+        _buf = "";
+    }
+    return 1;
+};