Add autostart option to BusABC.send_periodic() to fix issue #1848

can/broadcastmanager.py

@@ -276,6 +276,7 @@ def __init__(
         period: float,
         duration: Optional[float] = None,
         on_error: Optional[Callable[[Exception], bool]] = None,
+        autostart: bool = True,
         modifier_callback: Optional[Callable[[Message], None]] = None,
     ) -> None:
         """Transmits `messages` with a `period` seconds for `duration` seconds on a `bus`.
@@ -324,7 +325,8 @@ def __init__(
                 stacklevel=1,
             )
 
-        self.start()
+        if autostart:
+            self.start()
 
     def stop(self) -> None:
         self.stopped = True

can/bus.py

@@ -215,6 +215,7 @@ def send_periodic(
         period: float,
         duration: Optional[float] = None,
         store_task: bool = True,
+        autostart: bool = True,
         modifier_callback: Optional[Callable[[Message], None]] = None,
     ) -> can.broadcastmanager.CyclicSendTaskABC:
         """Start sending messages at a given period on this bus.
@@ -237,6 +238,9 @@ def send_periodic(
         :param store_task:
             If True (the default) the task will be attached to this Bus instance.
             Disable to instead manage tasks manually.
+        :param autostart:
+            If True (the default) the sending task will immediately start after creation.
+            Otherwise, the task has to be started by calling start() on it.
         :param modifier_callback:
             Function which should be used to modify each message's data before
             sending. The callback modifies the :attr:`~can.Message.data` of the
@@ -272,7 +276,7 @@ def send_periodic(
         # Create a backend specific task; will be patched to a _SelfRemovingCyclicTask later
         task = cast(
             _SelfRemovingCyclicTask,
-            self._send_periodic_internal(msgs, period, duration, modifier_callback),
+            self._send_periodic_internal(msgs, period, duration, autostart, modifier_callback),
         )
         # we wrap the task's stop method to also remove it from the Bus's list of tasks
         periodic_tasks = self._periodic_tasks
@@ -299,6 +303,7 @@ def _send_periodic_internal(
         msgs: Union[Sequence[Message], Message],
         period: float,
         duration: Optional[float] = None,
+        autostart: bool = True,
         modifier_callback: Optional[Callable[[Message], None]] = None,
     ) -> can.broadcastmanager.CyclicSendTaskABC:
         """Default implementation of periodic message sending using threading.
@@ -312,6 +317,9 @@ def _send_periodic_internal(
         :param duration:
             The duration between sending each message at the given rate. If
             no duration is provided, the task will continue indefinitely.
+        :param autostart:
+            If True (the default) the sending task will immediately start after creation.
+            Otherwise, the task has to be started by calling start() on it.
         :return:
             A started task instance. Note the task can be stopped (and
             depending on the backend modified) by calling the
@@ -328,6 +336,7 @@ def _send_periodic_internal(
             messages=msgs,
             period=period,
             duration=duration,
+            autostart=autostart,
             modifier_callback=modifier_callback,
         )
         return task

can/interfaces/ixxat/canlib.py

@@ -155,10 +155,11 @@ def _send_periodic_internal(
         msgs: Union[Sequence[Message], Message],
         period: float,
         duration: Optional[float] = None,
+        autostart: bool = True,
         modifier_callback: Optional[Callable[[Message], None]] = None,
     ) -> CyclicSendTaskABC:
         return self.bus._send_periodic_internal(
-            msgs, period, duration, modifier_callback
+            msgs, period, duration, autostart, modifier_callback
         )
 
     def shutdown(self) -> None:

can/interfaces/ixxat/canlib_vcinpl.py

@@ -793,6 +793,7 @@ def _send_periodic_internal(
         msgs: Union[Sequence[Message], Message],
         period: float,
         duration: Optional[float] = None,
+        autostart: bool = True,
         modifier_callback: Optional[Callable[[Message], None]] = None,
     ) -> CyclicSendTaskABC:
         """Send a message using built-in cyclic transmit list functionality."""
@@ -821,6 +822,7 @@ def _send_periodic_internal(
             msgs=msgs,
             period=period,
             duration=duration,
+            autostart=autostart,
             modifier_callback=modifier_callback,
         )
 

can/interfaces/ixxat/canlib_vcinpl2.py

@@ -937,6 +937,7 @@ def _send_periodic_internal(
         msgs: Union[Sequence[Message], Message],
         period: float,
         duration: Optional[float] = None,
+        autostart: bool = True,
         modifier_callback: Optional[Callable[[Message], None]] = None,
     ) -> CyclicSendTaskABC:
         """Send a message using built-in cyclic transmit list functionality."""
@@ -967,6 +968,7 @@ def _send_periodic_internal(
             msgs=msgs,
             period=period,
             duration=duration,
+            autostart=autostart,
             modifier_callback=modifier_callback,
         )
 

can/interfaces/socketcan/socketcan.py

@@ -813,6 +813,7 @@ def _send_periodic_internal(
         msgs: Union[Sequence[Message], Message],
         period: float,
         duration: Optional[float] = None,
+        autostart: bool = True,
         modifier_callback: Optional[Callable[[Message], None]] = None,
     ) -> can.broadcastmanager.CyclicSendTaskABC:
         """Start sending messages at a given period on this bus.
@@ -823,13 +824,16 @@ def _send_periodic_internal(
         :class:`CyclicSendTask` within BCM provides flexibility to schedule
         CAN messages sending with the same CAN ID, but different CAN data.
 
-        :param messages:
+        :param msgs:
             The message(s) to be sent periodically.
         :param period:
             The rate in seconds at which to send the messages.
         :param duration:
             Approximate duration in seconds to continue sending messages. If
             no duration is provided, the task will continue indefinitely.
+        :param autostart:
+            If True (the default) the sending task will immediately start after creation.
+            Otherwise, the task has to be started by calling start() on it.
 
         :raises ValueError:
             If task identifier passed to :class:`CyclicSendTask` can't be used
@@ -868,6 +872,7 @@ def _send_periodic_internal(
             msgs=msgs,
             period=period,
             duration=duration,
+            autostart=autostart,
             modifier_callback=modifier_callback,
         )