Cancelling asynchronous tasks has no effect?

  ros2/rclpy#1099

Signed-off-by: Tomoya Fujita <[email protected]>

prover_rclpy/setup.py

@@ -71,6 +71,8 @@
             'rclpy_1046 = src.rclpy_1046:main',
             'rclpy_1047 = src.rclpy_1047:main',
             'rclpy_1098 = src.rclpy_1098:main',
+            'rclpy_1099 = src.rclpy_1099:main',
+            'rclpy_1099_2 = src.rclpy_1099_2:main',
             'rclpy_1132 = src.rclpy_1132:main',
             'rclpy_1149 = src.rclpy_1149:main',
             'rclpy_1159 = src.rclpy_1159:main',

prover_rclpy/src/rclpy_1099.py

@@ -0,0 +1,52 @@
+
+import rclpy
+from rclpy.node import Node
+from rclpy.task import Future
+from rclpy.callback_groups import MutuallyExclusiveCallbackGroup
+
+
+def sleep_async(node: Node, time: float) -> Future:
+    """
+    Sleeps for a given amount of time.
+
+    Creates a timer with the sleep time as frequency and destroys it on the first callback.
+
+    args:
+        node: The node to sleep on. Future will be created with the nodes executor.
+        time: The time to sleep in seconds
+
+    returns:
+        A future that will be done after the given amount of time.
+    """
+    future = Future(executor=node.executor)
+    timer = node.create_timer(timer_period_sec=time, callback=lambda: _timer_callback(future), callback_group=MutuallyExclusiveCallbackGroup())
+
+    def _timer_callback(future: Future):
+        future.set_result(None)
+        node.destroy_timer(timer)
+
+    return future
+
+async def sleep(self, seconds):
+    for i in range(1, seconds+1):
+        await sleep_async(self, 1)
+        print(f"Slept for {i} seconds")
+
+
+def main(args=None):
+    rclpy.init()
+
+    node = rclpy.create_node("test")
+    executor = rclpy.get_global_executor()
+    executor.add_node(node)
+    task = executor.create_task(sleep, node, 5)
+
+    task.cancel()
+    print(f"{task.cancelled()=}")
+    executor.spin_until_future_complete(task)
+
+    print(f"{task.done()=}")
+    print(f"{task.cancelled()=}")
+
+if __name__ == '__main__':
+    main()

prover_rclpy/src/rclpy_1099_2.py

@@ -0,0 +1,34 @@
+import rclpy
+
+
+async def test_cancel():
+    future = rclpy.task.Future()
+    future.cancel()
+
+    print(future, future.cancelled(), future.done())
+
+    return await future
+
+
+def main(args=None):
+    rclpy.init()
+
+    node = rclpy.create_node("test")
+
+    def timer_callback():
+        node.get_logger().info("Logging timer fired.")
+
+    node.create_timer(1.0, timer_callback)
+
+    executor = rclpy.get_global_executor()
+    executor.add_node(node)
+    task = executor.create_task(test_cancel)
+
+    print(f"{task.cancelled()=}")
+    #task.cancel()
+    executor.spin_until_future_complete(task)
+    print(f"{task.done()=}")
+    print(f"{task.cancelled()=}")
+
+if __name__ == '__main__':
+    main()