Added support for continuous checks on distance sensor and DistanceSensorEvent

platypush/message/event/__init__.py

@@ -11,6 +11,7 @@ from platypush.config import Config
 from platypush.message import Message
 from platypush.utils import get_event_class_by_type
 
+
 class Event(Message):
     """ Event message class """
 
@@ -39,6 +40,9 @@ class Event(Message):
         self.args = kwargs
         self.disable_logging = disable_logging
 
+        for arg, value in self.args.items():
+            self.__setattr__(arg, value)
+
     @classmethod
     def build(cls, msg):
         """ Builds an event message from a JSON UTF-8 string/bytearray, a
@@ -55,16 +59,14 @@ class Event(Message):
         args['timestamp'] = msg['_timestamp'] if '_timestamp' in msg else time.time()
         return event_class(**args)
 
-
     @staticmethod
     def _generate_id():
         """ Generate a unique event ID """
         id = ''
-        for i in range(0,16):
+        for i in range(0, 16):
             id += '%.2x' % random.randint(0, 255)
         return id
 
-
     def matches_condition(self, condition):
         """
         If the event matches an event condition, it will return an EventMatchResult
@@ -75,7 +77,8 @@ class Event(Message):
         result = EventMatchResult(is_match=False, parsed_args=self.args)
         match_scores = []
 
-        if not isinstance(self, condition.type): return result
+        if not isinstance(self, condition.type):
+            return result
 
         for (attr, value) in condition.args.items():
             if attr not in self.args:
@@ -100,7 +103,6 @@ class Event(Message):
 
         return result
 
-
     def _matches_argument(self, argname, condition_value):
         """
         Returns an EventMatchResult if the event argument [argname] matches
@@ -147,9 +149,8 @@ class Event(Message):
                     else:
                         result.parsed_args[argname] += ' ' + event_token
 
-
                     if (len(condition_tokens) == 1 and len(event_tokens) == 1) \
-                            or (len(event_tokens) > 1 and len(condition_tokens) > 1 \
+                            or (len(event_tokens) > 1 and len(condition_tokens) > 1
                                 and event_tokens[1] == condition_tokens[1]):
                         # Stop appending tokens to this argument, as the next
                         # condition will be satisfied as well
@@ -164,7 +165,6 @@ class Event(Message):
         result.is_match = len(condition_tokens) == 0
         return result
 
-
     def __str__(self):
         """
         Overrides the str() operator and converts
@@ -175,13 +175,13 @@ class Event(Message):
         flatten(args)
 
         return json.dumps({
-            'type'     : 'event',
+            'type': 'event',
-            'target'   : self.target,
+            'target': self.target,
-            'origin'   : self.origin if hasattr(self, 'origin') else None,
+            'origin': self.origin if hasattr(self, 'origin') else None,
-            'id'       : self.id if hasattr(self, 'id') else None,
+            'id': self.id if hasattr(self, 'id') else None,
-            '_timestamp' : self.timestamp,
+            '_timestamp': self.timestamp,
-            'args'     : {
+            'args': {
-                'type' : self.type,
+                'type': self.type,
                 **args
             },
         })
@@ -226,18 +226,16 @@ class StopEvent(Event):
 
 def flatten(args):
     if isinstance(args, dict):
-        for (key,value) in args.items():
+        for (key, value) in args.items():
             if isinstance(value, date):
                 args[key] = value.isoformat()
             elif isinstance(value, dict) or isinstance(value, list):
                 flatten(args[key])
     elif isinstance(args, list):
-        for i in range(0,len(args)):
+        for i in range(0, len(args)):
             if isinstance(args[i], date):
-                args[i] = value.isoformat()
+                args[i] = args[i].isoformat()
             elif isinstance(args[i], dict) or isinstance(args[i], list):
                 flatten(args[i])
 
-
 # vim:sw=4:ts=4:et:
-

platypush/message/event/distance.py

@@ -0,0 +1,12 @@
+from platypush.message.event import Event
+
+
+class DistanceSensorEvent(Event):
+    """
+    Event triggered when a new value is processed by a distance sensor.
+    """
+    def __init__(self, distance: float, unit: str = 'mm', *args, **kwargs):
+        super().__init__(*args, distance=distance, unit=unit, **kwargs)
+
+
+# vim:sw=4:ts=4:et:

platypush/plugins/gpio/__init__.py

@@ -176,6 +176,9 @@ class GpioPlugin(Plugin):
         Cleanup the state of the GPIO and resets PIN values.
         """
         import RPi.GPIO as GPIO
+
+        with self._init_lock:
+            if self._initialized:
                 GPIO.cleanup()
                 self._initialized_pins = {}
                 self._initialized = False

platypush/plugins/gpio/sensor/distance/__init__.py

@@ -1,5 +1,10 @@
+import threading
 import time
 
+from typing import Optional
+
+from platypush.context import get_bus
+from platypush.message.event.distance import DistanceSensorEvent
 from platypush.plugins import action
 from platypush.plugins.gpio import GpioPlugin
 from platypush.plugins.gpio.sensor import GpioSensorPlugin
@@ -13,6 +18,11 @@ class GpioSensorDistancePlugin(GpioPlugin, GpioSensorPlugin):
     Requires:
 
         * ``RPi.GPIO`` (``pip install RPi.GPIO``)
+
+    Triggers:
+
+        * :class:`platypush.message.event.distance.DistanceSensorEvent` when a new distance measurement is available
+
     """
 
     def __init__(self, trigger_pin: int, echo_pin: int,
@@ -31,20 +41,27 @@ class GpioSensorDistancePlugin(GpioPlugin, GpioSensorPlugin):
             for the sensor to be ready (default: 2 seconds).
         """
 
-        GpioPlugin.__init__(self, *args, **kwargs)
+        GpioPlugin.__init__(self, pins={'trigger': trigger_pin, 'echo': echo_pin, }, *args, **kwargs)
+
         self.trigger_pin = trigger_pin
         self.echo_pin = echo_pin
         self.timeout = timeout
         self.warmup_time = warmup_time
-        self._initialized = False
+        self._measurement_thread: Optional[threading.Thread] = None
-        self._init_gpio()
+        self._measurement_thread_lock = threading.RLock()
+        self._measurement_thread_can_run = False
+        self._init_board()
 
-    def _init_gpio(self):
+    def _init_board(self):
+        import RPi.GPIO as GPIO
+
+        with self._init_lock:
             if self._initialized:
                 return
 
-        import RPi.GPIO as GPIO
+            GpioPlugin._init_board(self)
-        GPIO.setmode(self.mode)
+            self._initialized = False
+
             GPIO.setup(self.trigger_pin, GPIO.OUT)
             GPIO.setup(self.echo_pin, GPIO.IN)
             GPIO.output(self.trigger_pin, GPIO.LOW)
@@ -59,7 +76,7 @@ class GpioSensorDistancePlugin(GpioPlugin, GpioSensorPlugin):
 
         pulse_start = pulse_on = time.time()
 
-        self._init_gpio()
+        self._init_board()
         GPIO.output(self.trigger_pin, GPIO.HIGH)
         time.sleep(0.00001)  # 1 us pulse to trigger echo measurement
         GPIO.output(self.trigger_pin, GPIO.LOW)
@@ -94,7 +111,10 @@ class GpioSensorDistancePlugin(GpioPlugin, GpioSensorPlugin):
         """
 
         try:
-            return self._get_data()
+            distance = self._get_data()
+            bus = get_bus()
+            bus.post(DistanceSensorEvent(distance=distance, unit='mm'))
+            return distance
         except TimeoutError as e:
             self.logger.warning(str(e))
             return
@@ -104,16 +124,67 @@ class GpioSensorDistancePlugin(GpioPlugin, GpioSensorPlugin):
 
     @action
     def close(self):
-        import RPi.GPIO as GPIO
+        return self.cleanup()
-        if self._initialized:
-            GPIO.cleanup()
-            self._initialized = False
 
     def __enter__(self):
-        self._init_gpio()
+        self._init_board()
 
     def __exit__(self):
         self.close()
 
+    def _get_measurement_thread(self, duration: float):
+        def _thread():
+            with self:
+                start_time = time.time()
+
+                try:
+                    while self._measurement_thread_can_run and (
+                            not duration or time.time() - start_time <= duration):
+                        self.get_measurement()
+                finally:
+                    self._measurement_thread = None
+
+        return _thread
+
+    def _is_measurement_thread_running(self):
+        with self._measurement_thread_lock:
+            return self._measurement_thread is not None
+
+    @action
+    def start_measurement(self, duration: Optional[float] = None):
+        """
+        Start the measurement thread. It will trigger :class:`platypush.message.event.distance.DistanceSensorEvent`
+        events when new measurements are available.
+
+        :param duration: If set, then the thread will run for the specified amount of seconds (default: None)
+        """
+        with self._measurement_thread_lock:
+            if self._is_measurement_thread_running():
+                self.logger.warning('A measurement thread is already running')
+                return
+
+            thread_func = self._get_measurement_thread(duration=duration)
+            self._measurement_thread = threading.Thread(target=thread_func)
+            self._measurement_thread_can_run = True
+            self._measurement_thread.start()
+
+    @action
+    def stop_measurement(self):
+        """
+        Stop the running measurement thread.
+        """
+        with self._measurement_thread_lock:
+            if not self._is_measurement_thread_running():
+                self.logger.warning('No measurement thread is running')
+                return
+
+            self._measurement_thread_can_run = False
+            self.logger.info('Waiting for the measurement thread to end')
+
+            if self._measurement_thread:
+                self._measurement_thread.join(timeout=self.timeout)
+
+            self.logger.info('Measurement thread terminated')
+
 
 # vim:sw=4:ts=4:et: