From a2a5a924bdd983c729b65b567aa61adf64478188 Mon Sep 17 00:00:00 2001
From: Wolfgang Hottgenroth <w.hottgenroth@krohne.com>
Date: Tue, 25 Jun 2019 17:26:23 +0200
Subject: [PATCH] mqtt handling

---
 snippets/test8.py | 86 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 72 insertions(+), 14 deletions(-)

diff --git a/snippets/test8.py b/snippets/test8.py
index 4b57a1a..a77e984 100644
--- a/snippets/test8.py
+++ b/snippets/test8.py
@@ -4,6 +4,15 @@ import threading
 import socketserver
 import cmd
 import io
+import paho.mqtt.client as mqtt
+
+
+class Config(object):
+    def __init__(self):
+        self.mqttBrokerHost = '127.0.0.1'
+        self.mqttBrokerPort = 1883
+        self.mqttLogin = ''
+        self.mqttPassword = ''
 
 
 
@@ -31,6 +40,8 @@ class AbstractModbusDatapoint(object):
         self.count = count
         self.scanRate = scanRate
         self.type = 'abstract data point'
+        self.command = None
+        self.value = None
         self.enqueued = False
         if self.scanRate:
             self.priority = 1
@@ -45,7 +56,13 @@ class AbstractModbusDatapoint(object):
     def __ge__(self, other): return self.priority >= other.priority
 
     def __str__(self):
-        return "{0}, {1}: {2} {3} {4}".format(self.type, self.label, self.unit, self.address, self.count)
+        return "{0}, {1}: {2} {3} {4} {5} {6}".format(self.type, self.label, self.unit, self.address, self.count, self.command, self.value)
+    
+    def setCommand(self, cmd):
+        self.command = cmd
+    
+    def setValue(self, value):
+        self.value = value
 
 
 class HoldingRegisterDatapoint(AbstractModbusDatapoint):
@@ -87,32 +104,72 @@ class HoldingRegisterDatapoint(AbstractModbusDatapoint):
         self.writeRequestValue = value
 
 
+def mqttOnConnectCallback(client, userdata, flags, rc):
+    userdata.onConnect()
+
+def mqttOnMessageCallback(client, userdata, message):
+    userdata.onMessage(message.topic, message.payload)
+
+def mqttOnDisconnectCallback(client, userdata, rc):
+    userdata.onDisconnect(rc)
+
 class MqttProcessor(threading.Thread, AbstractNotificationReceiver):
     def __init__(self, registers, queue):
         super(MqttProcessor, self).__init__()
         self.registers = registers
         self.queue = queue
+        self.client = mqtt.Client(userdata=self)
+        self.subscriptions = []
+        self.topicRegisterMap ={}
+
+    def __processUpdatedRegisters(self, force=False):
+        # print("MqttProcessor.__updateSubscriptions")
+
+        subscribeTopics = [ r.subscribeTopic for r in self.registers if r.subscribeTopic]
+        # print("Topics: {0!s}".format(subscribeTopics))
+
+        for subscribeTopic in subscribeTopics:
+            if (subscribeTopic not in self.subscriptions) or force:
+                print("Subscribe to {0}".format(subscribeTopic))
+                self.client.subscribe(subscribeTopic)
+                self.subscriptions.append(subscribeTopic)
+
+        for subscription in self.subscriptions:
+            if (subscription not in subscribeTopics) and not force:
+                print("Unsubscribe from {0}".format(subscription))
+                self.client.unsubscribe(subscription)
+                self.subscriptions.remove(subscription)
+
+        self.topicRegisterMap = { r.subscribeTopic: r for r in self.registers if r.subscribeTopic }
 
     def receiveNotification(self, arg):
         print("MqttProcessor:registersChanged")
-        pass
-        # subscribe and/or unsubscribe according to register changes
+        self.__processUpdatedRegisters()
 
     def run(self):
-        pass
-        # set mqtt callbacks
-        # mqtt connect
-        # mqtt loop forever
+        # print("MqttProcessor.run")
+        self.client.on_message = mqttOnMessageCallback
+        self.client.on_connect = mqttOnConnectCallback
+        self.client.on_disconnect = mqttOnDisconnectCallback
+        if config.mqttLogin and config.mqttPassword:
+            self.client.username_pw_set(config.mqttLogin, config.mqttPassword)
+        self.client.connect(config.mqttBrokerHost, config.mqttBrokerPort)
+        self.client.loop_forever()
 
     def onConnect(self):
-        pass
-        # subscribe to all subscribe topics from registers
+        # print("MqttProcessor.onConnect")
+        self.__processUpdatedRegisters(force=True)
+
+    def onDisconnect(self, rc):
+        print("Disconnected from MQTT broker: {0}".format(rc))
 
     def onMessage(self, topic, payload):
-        pass
-        # call onMessage method of register with related subscribe topic
-        # put register yourself in high prio queue
-        # self.put(r)
+        # print("MqttProcessor.onMessage")
+        r = self.topicRegisterMap[topic]
+        # print("{0}: {1!s} -> {2!s}".format(topic, payload, r))
+        r.setCommand('w')
+        r.setValue(payload)
+        self.queue.put(r)
 
 
 class ScanRateConsideringQueueFeeder(threading.Thread, AbstractNotificationReceiver):
@@ -140,6 +197,7 @@ class ScanRateConsideringQueueFeeder(threading.Thread, AbstractNotificationRecei
             ]
             registersToBeHandled.sort(key=lambda x : x.scanRate)
             for r in registersToBeHandled:
+                r.setCommand('r')
                 self.queue.put(r)
                 r.enqueued = True
             self.delayEvent.wait(self.delay)
@@ -210,7 +268,7 @@ datapoints = [
 
 queue = queue.PriorityQueue()
 nf = NotificationForwarder()
-
+config = Config()
 
 if __name__ == "__main__":
     cp = CommunicationProcessor(queue)