Add asyncio action server example

rclpy/actions/minimal_action_server/examples_rclpy_minimal_action_server/server_asyncio.py

@@ -0,0 +1,123 @@
+# Copyright 2019 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import asyncio
+
+import rclpy
+from example_interfaces.action import Fibonacci
+from rclpy.action import ActionServer, CancelResponse, GoalResponse
+from rclpy.callback_groups import ReentrantCallbackGroup
+from rclpy.executors import MultiThreadedExecutor
+from rclpy.node import Node
+
+
+def asyncio_loop(func):
+    def wrapper(*args, **kwargs):
+        return asyncio.new_event_loop().run_until_complete(
+            func(*args, **kwargs))
+
+    return wrapper
+
+
+class MinimalActionServerAsyncIO(Node):
+
+    def __init__(self):
+        super().__init__('minimal_action_server_asyncio')
+
+        self._action_server = ActionServer(
+            self,
+            Fibonacci,
+            'fibonacci',
+            execute_callback=self.execute_callback,
+            callback_group=ReentrantCallbackGroup(),
+            goal_callback=self.goal_callback,
+            cancel_callback=self.cancel_callback)
+
+    def destroy(self):
+        self._action_server.destroy()
+        super().destroy_node()
+
+    def goal_callback(self, goal_request):
+        """Accept or reject a client request to begin an action."""
+        # This server allows multiple goals in parallel
+        self.get_logger().info('Received goal request')
+        return GoalResponse.ACCEPT
+
+    def cancel_callback(self, goal_handle):
+        """Accept or reject a client request to cancel an action."""
+        self.get_logger().info('Received cancel request')
+        return CancelResponse.ACCEPT
+
+    @asyncio_loop
+    async def execute_callback(self, goal_handle):
+        """Execute a goal."""
+        self.get_logger().info('Executing goal...')
+
+        # Append the seeds for the Fibonacci sequence
+        feedback_msg = Fibonacci.Feedback()
+        feedback_msg.sequence = [0, 1]
+
+        # Start executing the action
+        for i in range(1, goal_handle.request.order):
+            if goal_handle.is_cancel_requested:
+                goal_handle.canceled()
+                self.get_logger().info('Goal canceled')
+                return Fibonacci.Result()
+
+            # Update Fibonacci sequence
+            feedback_msg.sequence.append(
+                feedback_msg.sequence[i] + feedback_msg.sequence[i - 1])
+
+            self.get_logger().info(
+                'Publishing feedback: {0}'.format(feedback_msg.sequence))
+
+            # Publish the feedback
+            goal_handle.publish_feedback(feedback_msg)
+
+            # Sleep for demonstration purposes
+            await asyncio.sleep(1)
+
+        goal_handle.succeed()
+
+        # Populate result message
+        result = Fibonacci.Result()
+        result.sequence = feedback_msg.sequence
+
+        self.get_logger().info('Returning result: {0}'.format(result.sequence))
+
+        return result
+
+
+def main(args=None):
+    # init ros2
+    rclpy.init(args=args)
+
+    # Use a MultiThreadedExecutor to enable processing goals concurrently
+    executor = MultiThreadedExecutor()
+
+    # create node
+    action_server = MinimalActionServerAsyncIO()
+
+    # add node
+    executor.add_node(action_server)
+
+    # spin
+    executor.spin()
+
+    action_server.destroy()
+    rclpy.shutdown()
+
+
+if __name__ == '__main__':
+    main()

rclpy/actions/minimal_action_server/setup.py

@@ -34,6 +34,7 @@
             'server_not_composable = ' + package_name + '.server_not_composable:main',
             'server_queue_goals = ' + package_name + '.server_queue_goals:main',
             'server_single_goal = ' + package_name + '.server_single_goal:main',
+            'server_asyncio = ' + package_name + '.server_asyncio:main',
         ],
     },
 )