termination mechanism integrated

src/AbstractMqttHandler.py

@@ -22,6 +22,10 @@ class AbstractMqttPublisher(threading.Thread):
 
         self.client = mqtt.Client(userdata=self)
 
+        # consider this flag in the localLoop
+        self.killBill = False
+        self.killEvent = threading.Event()
+
     def run(self):
         self.client.on_message = mqttOnMessageCallback
         self.client.on_connect = mqttOnConnectCallback
@@ -39,6 +43,18 @@ class AbstractMqttPublisher(threading.Thread):
     def localLoop(self):
         raise NotImplementedError()
 
+    def stop(self):
+        self.client.loop_stop()
+        logger.info("mqtt loop stopped")
+        
+        self.killBill = True
+        logger.info("kill flag set")
+
+        self.killEvent.set()
+        with self.processImage:
+            self.processImage.notify()
+        logger.info("kill events triggered")
+
     def onConnect(self):
         logger.info("mqtt connected")
     

src/ModbusHandler.py

@@ -5,79 +5,86 @@ import threading
 from loguru import logger
 
 
-def modbusStart(config, processImage):
+
-    modbusThread = threading.Thread(target=modbusHandler, args=[config, processImage])
+class ModbusHandler(threading.Thread):
-    modbusThread.start()
+    def __init__(self, config, processImage):
+        super().__init__()
+
+        self.config = config["modbus"]
+        self.processImage = processImage
+        self.killBill = False
+
+    def stop(self):
+        self.killBill = True
+
+    def run(self):
+        modbusClient = self.config["client"]
+        modbusRefreshPeriod = float(self.config["scanrate"])
+
+        client = ModbusClient(modbusClient)
 
 
-def modbusHandler(config, processImage):
+        try:
-    modbusClient = config["modbus"]["client"]
+            client.connect()
-    modbusRefreshPeriod = float(config["modbus"]["scanrate"])
 
+            res = client.read_holding_registers(0x1010, 4)
+            if isinstance(res, ModbusIOException):
+                raise Exception(self.processImage)
 
-    client = ModbusClient(modbusClient)
+            if len(res.registers) != 4:
+                raise Exception("Unexpected number of registers for process image ({})".format(len(res.registers)))
 
-    try:
+            (analogOutputBits, analogInputBits, digitalOutputBits, digitalInputBits) = res.registers
-        client.connect()
+            logger.debug(f"AO: {analogOutputBits}, AI: {analogInputBits}, DO: {digitalOutputBits}, DI: {digitalInputBits}")
 
-        res = client.read_holding_registers(0x1010, 4)
+            self.processImage.init(digitalOutputBits, digitalInputBits, analogInputBits)
-        if isinstance(res, ModbusIOException):
-            raise Exception(processImage)
 
-        if len(res.registers) != 4:
+            reg = client.read_coils(0, digitalOutputBits)
-            raise Exception("Unexpected number of registers for process image ({})".format(len(res.registers)))
+            if isinstance(reg, ModbusIOException):
+                raise Exception(reg)
+            with self.processImage:
+                self.processImage.setCoils(reg.bits)
 
-        (analogOutputBits, analogInputBits, digitalOutputBits, digitalInputBits) = res.registers
+            while not self.killBill:
-        logger.debug(f"AO: {analogOutputBits}, AI: {analogInputBits}, DO: {digitalOutputBits}, DI: {digitalInputBits}")
+                try:
+                    if not client.is_socket_open():
+                        client.connect()
 
-        processImage.init(digitalOutputBits, digitalInputBits, analogInputBits)
+                    reg = client.read_input_registers(0, analogInputBits // 8)
-
-        reg = client.read_coils(0, digitalOutputBits)
-        if isinstance(reg, ModbusIOException):
-            raise Exception(reg)
-        with processImage:
-            processImage.setCoils(reg.bits)
-
-        while True:
-            try:
-                if not client.is_socket_open():
-                    client.connect()
-
-                reg = client.read_input_registers(0, analogInputBits // 8)
-                if isinstance(reg, ModbusIOException):
-                    raise Exception(reg)
-                analogInputs = reg.registers
-
-                reg = client.read_discrete_inputs(0, digitalInputBits)
-                if isinstance(reg, ModbusIOException):
-                    raise Exception(reg)
-                discreteInputs = reg.bits
-
-                coils = None
-                with processImage:
-                    processImage.setAnalogsInputs(analogInputs)
-                    processImage.setDiscreteInputs(discreteInputs)
-                    if processImage.hasPendingInputChanges():
-                        processImage.notify()
-                    if processImage.hasPendingOutputChanges():
-                        coils = processImage.getCoils()
-
-                if coils:
-                    logger.debug("write coils to device: {}".format(coils))
-                    reg = client.write_coils(0, coils)
                     if isinstance(reg, ModbusIOException):
                         raise Exception(reg)
+                    analogInputs = reg.registers
 
-            except Exception as e:
+                    reg = client.read_discrete_inputs(0, digitalInputBits)
-                logger.error("Exception in inner modbus handler loop: {}".format(e))
+                    if isinstance(reg, ModbusIOException):
-                client.close()
+                        raise Exception(reg)
-            finally:
+                    discreteInputs = reg.bits
-                #sleep(modbusRefreshPeriod)
+
-                if (processImage.coilEvent.wait(timeout=modbusRefreshPeriod)):
+                    coils = None
-                    processImage.coilEvent.clear()
+                    with self.processImage:
+                        self.processImage.setAnalogsInputs(analogInputs)
+                        self.processImage.setDiscreteInputs(discreteInputs)
+                        if self.processImage.hasPendingInputChanges():
+                            self.processImage.notify()
+                        if self.processImage.hasPendingOutputChanges():
+                            coils = self.processImage.getCoils()
+
+                    if coils:
+                        logger.debug("write coils to device: {}".format(coils))
+                        reg = client.write_coils(0, coils)
+                        if isinstance(reg, ModbusIOException):
+                            raise Exception(reg)
+
+                except Exception as e:
+                    logger.error("Exception in inner modbus handler loop: {}".format(e))
+                    client.close()
+                finally:
+                    #sleep(modbusRefreshPeriod)
+                    if (self.processImage.coilEvent.wait(timeout=modbusRefreshPeriod)):
+                        self.processImage.coilEvent.clear()
 
 
-    except Exception as e:
+        except Exception as e:
-        logger.error("Exception in modbus handler: {}".format(e))
+            logger.error("Exception in modbus handler: {}".format(e))
-    finally:
+        finally:
-        client.close()
+            client.close()

src/MqttCoilSubscriber.py

@@ -14,7 +14,7 @@ class MqttCoilSubscriber(AbstractMqttPublisher):
         super().__init__(config, processImage)
 
     def localLoop(self):
-        while True:
+        while not self.killBill:
             sleep(float(self.config["analogInputPublishPeriod"]))
 
     def onMessage(self, topic, payload):

src/MqttEventPublisher.py

@@ -15,9 +15,11 @@ class MqttEventPublisher(AbstractMqttPublisher):
         self.disableAnalogInputEventPublishing = self.config["disableAnalogInputEventPublishing"].lower() in [ "true", "on" ]
 
     def localLoop(self):
-        while True:
+        while not self.killBill:
             with self.processImage:
                 self.processImage.wait()
+                if self.killBill:
+                    continue
 
                 discreteInputChangeset = self.processImage.getChangedDiscreteInputs()
                 if not self.disableAnalogInputEventPublishing:

src/MqttPeriodPublisher.py

@@ -1,8 +1,6 @@
-import paho.mqtt.client as mqtt
+from threading import Event
-import threading
 from loguru import logger
 from AbstractMqttHandler import AbstractMqttPublisher
-from time import sleep
 
 def mqttPeriodPublisherStart(config, processImage):
     mqttPeriodPublisherThread = MqttPeriodPublisher(config, processImage)
@@ -14,7 +12,7 @@ class MqttPeriodPublisher(AbstractMqttPublisher):
         super().__init__(config, processImage)
 
     def localLoop(self):
-        while True:
+        while not self.killBill:
             with self.processImage:
                 if not self.processImage.isInitialized():
                     continue
@@ -28,5 +26,5 @@ class MqttPeriodPublisher(AbstractMqttPublisher):
                 self.client.publish("{}/{}".format(self.config["analogInputPeriodicTopicPrefix"], str(analogInputItem[0])),
                                     str(analogInputItem[1]))
 
-            sleep(float(self.config["analogInputPublishPeriod"]))
+            self.killEvent.wait(timeout=float(self.config["analogInputPublishPeriod"]))
 

src/digitaltwin1.py

@@ -1,14 +1,23 @@
 from loguru import logger
 import argparse
 import configparser
+import threading
 
 from ProcessImage import ProcessImage
-from ModbusHandler import modbusStart
+from ModbusHandler import ModbusHandler
-from MqttEventPublisher import mqttEventPublisherStart
+from MqttEventPublisher import MqttEventPublisher, mqttEventPublisherStart
-from MqttPeriodPublisher import mqttPeriodPublisherStart
+from MqttPeriodPublisher import MqttPeriodPublisher
-from MqttCoilSubscriber import mqttCoilSubscriberStart
+from MqttCoilSubscriber import MqttCoilSubscriber
 
 
+deathBell = threading.Event()
+
+def exceptHook(args):
+    global deathBell
+    logger.error("Exception in thread caught: {}".format(args))
+    deathBell.set()
+    logger.error("rang the death bell")
+
 
 logger.info("DigitalTwin1 starting")
 
@@ -27,17 +36,44 @@ config.read(args.config)
 
 processImage = ProcessImage()
 
-modbusStart(config, processImage)
+modbusHandlerThread = ModbusHandler(config, processImage)
+modbusHandlerThread.start()
 logger.info("Modbus handler running")
 
-mqttEventPublisherStart(config, processImage)
+mqttEventPublisherThread = MqttEventPublisher(config, processImage)
+mqttEventPublisherThread.start()
 logger.info("MQTT event publisher running")
 
-mqttPeriodPublisherStart(config, processImage)
+mqttPeriodPublisherThread = MqttPeriodPublisher(config, processImage)
+mqttPeriodPublisherThread.start()
 logger.info("MQTT period publisher running")
 
-mqttCoilSubscriberStart(config, processImage)
+mqttCoilSubscriberThread = MqttCoilSubscriber(config, processImage)
+mqttCoilSubscriberThread.start()
 logger.info("MQTT coil subscriber running")
 
+threading.excepthook = exceptHook
+logger.info("Threading excepthook set")
+
 logger.info("DigitalTwin1 running")
 
+
+deathBell.wait()
+logger.error("DigitalTwin1 is dying")
+
+modbusHandlerThread.stop()
+mqttEventPublisherThread.stop()
+mqttPeriodPublisherThread.stop()
+mqttCoilSubscriberThread.stop()
+
+modbusHandlerThread.join()
+logger.error("modbusHandlerThread joined")
+mqttEventPublisherThread.join()
+logger.error("mqttEventPublisherThread joined")
+mqttPeriodPublisherThread.join()
+logger.error("mqttPeriodPublisherThread joined")
+mqttCoilSubscriberThread.join()
+logger.error("mqttCoilSubscriberThread joined")
+
+logger.error("DigitalTwin1 to terminate")
+