Added functionality to skip sending messages based on probability (#8)

* NEW: Probability based message failure added. Off by default

src/iotswarm/devices.py

@@ -85,6 +85,25 @@ def mqtt_topic(self, value):
         self._mqtt_topic = value
         self.mqtt_base_topic = value
 
+    _no_send_probability = 0
+
+    @property
+    def no_send_probability(self) -> int:
+        """Defines the chance of data not being sent, can be 0 - 100"""
+        return self._no_send_probability
+
+    @no_send_probability.setter
+    def no_send_probability(self, probability: int) -> None:
+        """Setter for the no_send_probability attribute"""
+
+        if not isinstance(probability, int):
+            probability = round(probability)
+
+        if probability < 0 or probability > 100:
+            raise ValueError(f"`probability` must be between 0 - 100 inclusive, not '{probability}'")
+
+        self._no_send_probability = probability
+
     def __eq__(self, obj) -> bool:
 
         base_equality = (
@@ -97,6 +116,7 @@ def __eq__(self, obj) -> bool:
             and self._instance_logger == obj._instance_logger
             and self.data_source == obj.data_source
             and self.connection == obj.connection
+            and self.no_send_probability == obj.no_send_probability
         )
 
         table_equality = True
@@ -123,6 +143,7 @@ def __init__(
         mqtt_topic: str | None = None,
         mqtt_prefix: str | None = None,
         mqtt_suffix: str | None = None,
+        no_send_probability: int = 0
     ) -> None:
         """Initializer
 
@@ -137,6 +158,7 @@ def __init__(
             table: A valid table from the database
             mqtt_prefix: Prefixes the MQTT topic if MQTT messaging used.
             mqtt_suffix: Suffixes the MQTT topic if MQTT messaging used.
+            no_send_probability: Defines the probability of the device not sending a message.
         """
 
         self.device_id = str(device_id)
@@ -206,6 +228,8 @@ def __init__(
                 f"{self.__class__.__name__}-{self.device_id}"
             )
 
+        self.no_send_probability = no_send_probability
+
         self._instance_logger.info(f"Initialised Site: {repr(self)}")
 
     def __repr__(self):
@@ -249,6 +273,12 @@ def __repr__(self):
             if hasattr(self, "mqtt_suffix")
             else ""
         )
+
+        no_send_probability_arg = (
+            f", no_send_probability={self.no_send_probability}"
+            if self.no_send_probability != self.__class__._no_send_probability
+            else ""
+        )
         return (
             f"{self.__class__.__name__}("
             f'"{self.device_id}"'
@@ -261,6 +291,7 @@ def __repr__(self):
             f"{mqtt_topic_arg}"
             f"{mqtt_prefix_arg}"
             f"{mqtt_suffix_arg}"
+            f"{no_send_probability_arg}"
             f")"
         )
 
@@ -300,7 +331,9 @@ async def run(self):
 
             payload = await self._get_payload()
 
-            if payload is not None:
+            if self._skip_send():
+                self._instance_logger.debug(f"Skipped send based on probability: {self.no_send_probability}")
+            elif payload is not None:
                 payload = self._format_payload(payload)
 
                 self._instance_logger.debug("Requesting payload submission.")
@@ -344,6 +377,14 @@ def _format_payload(self, payload):
 
     def _attach_swarm(self, swarm: object):
         self.swarm = swarm
+
+    def _skip_send(self) -> bool:
+        """Checks if the sending should be skipped
+        
+        Returns: True or false based on the no_send_probability
+        """
+
+        return random.random() * 100 < self.no_send_probability
 
 
 class CR1000XDevice(BaseDevice):

src/iotswarm/scripts/cli.py

@@ -169,6 +169,7 @@ def mqtt(
     mqtt_suffix,
     dry,
     device_type,
+    no_send_probability,
 ):
     """Sends The cosmos data via MQTT protocol using IoT Core.
     Data is from the cosmos database TABLE and sent using CLIENT_ID.
@@ -217,6 +218,7 @@ async def _mqtt():
                 mqtt_prefix=mqtt_prefix,
                 mqtt_suffix=mqtt_suffix,
                 inherit_logger=ctx.obj["logger"],
+                no_send_probability=no_send_probability
             )
             for site in sites
         ]
@@ -284,6 +286,7 @@ def mqtt(
     dry,
     device_type,
     resume_session,
+    no_send_probability,
 ):
     """Sends The cosmos data via MQTT protocol using IoT Core.
     Data is collected from the db using QUERY and sent using CLIENT_ID.
@@ -314,6 +317,8 @@ async def _mqtt_resume_session():
                 swarm.devices[i].mqtt_prefix = mqtt_prefix
             if mqtt_suffix is not None:
                 swarm.devices[i].mqtt_suffix = mqtt_suffix
+            if no_send_probability is not None:
+                swarm.devices[i].no_send_probability = no_send_probability
 
         click.echo("Loaded swarm from pickle")
 
@@ -354,6 +359,7 @@ async def _mqtt_clean_session():
                 mqtt_prefix=mqtt_prefix,
                 mqtt_suffix=mqtt_suffix,
                 inherit_logger=ctx.obj["logger"],
+                no_send_probability=no_send_probability,
             )
             for site in sites
         ]
@@ -440,6 +446,7 @@ def mqtt(
     dry,
     device_type,
     resume_session,
+    no_send_probability,
 ):
     """Sends The cosmos data via MQTT protocol using IoT Core.
     Data is collected from the db using QUERY and sent using CLIENT_ID.
@@ -472,6 +479,8 @@ async def _mqtt_resume_session():
                 swarm.devices[i].mqtt_prefix = mqtt_prefix
             if mqtt_suffix is not None:
                 swarm.devices[i].mqtt_suffix = mqtt_suffix
+            if no_send_probability is not None:
+                swarm.devices[i].no_send_probability = no_send_probability
 
         click.echo(swarm.devices[0].cycle)
         click.echo("Loaded swarm from pickle")
@@ -514,6 +523,7 @@ async def _mqtt_clean_session():
                 mqtt_suffix=mqtt_suffix,
                 table=table,
                 inherit_logger=ctx.obj["logger"],
+                no_send_probability=no_send_probability
             )
             for site in sites
         ]

src/iotswarm/scripts/common.py

@@ -39,6 +39,12 @@ def device_options(function):
         "--device-type", type=click.Choice(["basic", "cr1000x"]), default="basic"
     )(function)
 
+    click.option(
+        "--no-send-probability",
+        type=click.IntRange(0, 100),
+        help="Probability of not sending a message, can be 0 - 100 where 0 is no skip and 100 is always skip",
+    )(function)
+
     return function
 
 

tests/test_devices.py

@@ -91,19 +91,20 @@ def test_connection_type_check(self, conn):
 
     @parameterized.expand(
         [
-            [0, 0, None, (0, 0, False)],
-            [100, 30, True, (100, 30, True)],
-            [12.4, 30001.9, None, (12, 30001, False)],
+            [0, 0, None, 5, (0, 0, False)],
+            [100, 30, True, 9, (100, 30, True)],
+            [12.4, 30001.9, None, 100, (12, 30001, False)],
         ]
     )
-    def test_optional_args_set(self, max_cycles, sleep_time, delay_start, expected):
+    def test_optional_args_set(self, max_cycles, sleep_time, delay_start,no_send_probability, expected):
         inst = BaseDevice(
             "TEST_ID",
             self.data_source,
             self.connection,
             max_cycles=max_cycles,
             sleep_time=sleep_time,
             delay_start=delay_start,
+            no_send_probability=no_send_probability
         )
 
         self.assertEqual(inst.max_cycles, expected[0])
@@ -166,6 +167,11 @@ def test_delay_start_value_check(self, delay_start):
                 {"max_cycles": 4, "sleep_time": 5, "delay_start": True},
                 'BaseDevice("TEST_ID", MockDB(), MockMessageConnection(), sleep_time=5, max_cycles=4, delay_start=True)',
             ],
+            [
+                MockDB(),
+                {"max_cycles": 4, "sleep_time": 5, "delay_start": True, "no_send_probability":10},
+                'BaseDevice("TEST_ID", MockDB(), MockMessageConnection(), sleep_time=5, max_cycles=4, delay_start=True, no_send_probability=10)',
+            ],
         ]
     )
     def test__repr__(self, data_source, kwargs, expected):
@@ -266,6 +272,40 @@ def test__repr__mqtt_opts_mqtt_connection(self, topic, prefix, suffix,expected_a
 
         self.assertEqual(inst.__repr__(), expected)
 
+class TestProbabilitySend(unittest.TestCase):
+    def setUp(self):
+        self.data_source = MockDB()
+        self.connection = MockMessageConnection()
+
+    @parameterized.expand([0, 10, 20, 50, 81, 100])
+    def test_probability_send(self, probability):
+        device = BaseDevice("ID", self.data_source, self.connection, no_send_probability=probability)
+
+        skipped = 0
+
+        for i in range(10000):
+            if device._skip_send():
+                skipped += 1
+
+        self.assertAlmostEqual(skipped/100, probability, delta=1)
+
+    def test_probability_zero_if_not_given(self):
+        device = BaseDevice("ID", self.data_source, self.connection)
+
+        self.assertEqual(device.no_send_probability, 0)
+
+    @parameterized.expand(["Four", None])
+    def test_probability_bad_values(self, value):
+
+        with self.assertRaises((TypeError, ValueError)):
+            device = BaseDevice("ID", self.data_source, self.connection, no_send_probability=value)
+
+    @parameterized.expand([[2,2], [0,0], [27.34, 27], [99.5, 100]])
+    def test_probability_set(self, value, expected):
+        device = BaseDevice("ID", self.data_source, self.connection, no_send_probability=value)
+
+        self.assertEqual(device.no_send_probability, expected)
+
 
 class TestBaseDeviceOracleUsed(unittest.IsolatedAsyncioTestCase):