High-Latency networks: "generator already executing" when calling a s…

…ervice

  ref: ros2/rclpy#1351

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

prover_rclpy/setup.py

@@ -79,6 +79,7 @@
             'rclpy_1273 = src.rclpy_1273:main',
             'rclpy_1287 = src.rclpy_1287:main',
             'rclpy_1303 = src.rclpy_1303:main',
+            'rclpy_1351 = src.rclpy_1351:main',
             'ros2cli_818 = src.ros2cli_818:main',
             'ros2cli_862 = src.ros2cli_862:main',
             'ros2cli_885 = src.ros2cli_885:main',

prover_rclpy/src/rclpy_1351.py

@@ -0,0 +1,37 @@
+import threading
+import time
+
+import rclpy
+from rclpy.executors import Executor
+from rclpy.executors import MultiThreadedExecutor
+from rclpy.executors import SingleThreadedExecutor
+from rclpy.task import Future
+
+
+def main(args=None):
+    rclpy.init(args=args)
+    executor = SingleThreadedExecutor()
+
+    future1 = Future(executor=executor)
+    future2 = Future(executor=executor)
+
+    # I believe that we need to use ThreadPoolExecutor here...
+    thread1 = threading.Thread(target=executor.spin_until_future_complete,
+                                args=(future1, 10))
+    thread2 = threading.Thread(target=executor.spin_until_future_complete,
+                                args=(future2, 10))
+
+    thread1.start()
+    time.sleep(0.5)
+    thread2.start()
+
+    future1.set_result(True)
+    future2.set_result(True)
+
+    thread1.join()
+    thread2.join()
+    executor.shutdown()
+
+
+if __name__ == '__main__':
+    main()