rclpy action examples #222

jacobperron · 2019-01-09T18:33:36Z

Replaces #216.

rclpy/actions/minimal_action_client/client_not_composable.py

sloretz · 2019-02-02T01:00:05Z

This is weird, possible setuptools bug? When I run the action client the service client example runs instead

ros2|sloretz@48174b4e204f:~/ws/ros2$ ros2 run examples_rclpy_minimal_action_client client
[INFO] [minimal_client]: service not available, waiting again...
[INFO] [minimal_client]: service not available, waiting again...
[INFO] [minimal_client]: service not available, waiting again...
[INFO] [minimal_client]: service not available, waiting again...
[INFO] [minimal_client]: service not available, waiting again...
[INFO] [minimal_client]: service not available, waiting again...
^CTraceback (most recent call last):
  File "/home/sloretz/ws/ros2/install/examples_rclpy_minimal_action_client/lib/examples_rclpy_minimal_action_client/client", line 11, in <module>
    load_entry_point('examples-rclpy-minimal-action-client==0.6.1', 'console_scripts', 'client')()
  File "/home/sloretz/ws/ros2/install/examples_rclpy_minimal_client/lib/python3.6/site-packages/client.py", line 28, in main
    while not cli.wait_for_service(timeout_sec=1.0):
  File "/home/sloretz/ws/ros2/install/rclpy/lib/python3.6/site-packages/rclpy/client.py", line 106, in wait_for_service
    time.sleep(sleep_time)
KeyboardInterrupt

setuptools warns the name must be unique within a 'distribution' but the entrypoint uses pkg_resources.load_entry_point which clearly shows the distribution is examples-rclpy-minimal-action-client==0.6.1, not the service client.

$ cat /home/sloretz/ws/ros2/install/examples_rclpy_minimal_action_client/lib/examples_rclpy_minimal_action_client/client
#!/usr/bin/python3
# EASY-INSTALL-ENTRY-SCRIPT: 'examples-rclpy-minimal-action-client==0.6.1','console_scripts','client'
__requires__ = 'examples-rclpy-minimal-action-client==0.6.1'
import re
import sys
from pkg_resources import load_entry_point

if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw?|\.exe)?$', '', sys.argv[0])
    sys.exit(
        load_entry_point('examples-rclpy-minimal-action-client==0.6.1', 'console_scripts', 'client')()
    )

rclpy/actions/minimal_action_client/setup.py

…r examples This package structure is consistent with examples for services and topics.

Now the 'simplest' example is 'server.py'.

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

jacobperron · 2019-02-07T21:02:14Z

Rebased on master and updated action server examples. This ready for review in conjunction with ros2/rclpy#270.

This avoid top-level module names from clashing when installed. Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

rclpy/actions/minimal_action_server/examples_rclpy_minimal_action_server/server.py

rclpy/actions/minimal_action_server/setup.py

sloretz · 2019-02-11T23:15:38Z

rclpy/actions/minimal_action_server/examples_rclpy_minimal_action_server/server_single_goal.py

+        """Executes the goal."""
+        self.get_logger().info('Executing goal...')
+        with self._goal_lock:
+            self._goal_handle = goal_handle


Is it possible for two goals to get through goal_callback before the first reaches execute_callback? In that case one of them will overwrite the other in self._goal_handle

Fixed with the use of handle_accepted_callback b0c739a

rclpy/actions/minimal_action_client/examples_rclpy_minimal_action_client/client.py

sloretz · 2019-02-11T23:27:07Z

rclpy/actions/minimal_action_server/examples_rclpy_minimal_action_server/server.py

+
+    def cancel_callback(self, goal_handle):
+        """Accepts or rejects a client request to cancel an action."""
+        self.get_logger().info('Received cancel request')


When running the cancel example this is the last log message I see. Both the client and the server continue to run. I was expecting to see the server say Goal canceld from line 67.

$ ros2 run examples_rclpy_minimal_action_client client_cancel [INFO] [minimal_action_client]: Waiting for action server... [INFO] [minimal_action_client]: Sending goal request... [INFO] [minimal_action_client]: Goal accepted :) [INFO] [minimal_action_client]: Received feedback: [0, 1, 1] [INFO] [minimal_action_client]: Received feedback: [0, 1, 1, 2] [INFO] [minimal_action_client]: Received feedback: [0, 1, 1, 2, 3] [INFO] [minimal_action_client]: Canceling goal

$ ros2 run examples_rclpy_minimal_action_server server [INFO] [minimal_action_server]: Received goal request [INFO] [minimal_action_server]: Executing goal... [INFO] [minimal_action_server]: Publishing feedback: [0, 1, 1] [INFO] [minimal_action_server]: Publishing feedback: [0, 1, 1, 2] [INFO] [minimal_action_server]: Publishing feedback: [0, 1, 1, 2, 3] [INFO] [minimal_action_server]: Received cancel request

Fixed in ce7bb67

I was making a synchronous call in a callback (which is no good, as documented 😞)

* Update author * Update copyright year * Shutdown client example after result received Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

This makes it easy to experiment with the scenario where a deferred goal is canceled prior to execution. Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

jacobperron · 2019-03-04T19:05:39Z

Ready for review.

Linux
Linux-aarch64
macOS
Windows

sloretz

LGTM, just a couple nitpick comments

rclpy/actions/minimal_action_client/examples_rclpy_minimal_action_client/client_cancel.py

sloretz · 2019-03-04T23:27:16Z

rclpy/actions/minimal_action_server/examples_rclpy_minimal_action_server/server.py

+            goal_handle.publish_feedback(feedback_msg)
+
+            # Sleep for demonstration purposes
+            time.sleep(1)


nit, should be able to use asyncio sleep to let the executor do other stuff (although, there's no other stuff being done in this example)

await asyncio.sleep(1)

Good point, but there must be a bug in rclpy because changing this to await asyncio.sleep(1) causes it to hang forever at this line. If I also change the executor to a SingleThreadedExecutor, then there's an assertion error with the following trace:

Traceback (most recent call last): File "/home/jacob/ws/actions_ws/install/examples_rclpy_minimal_action_server/lib/examples_rclpy_minimal_action_server/server", line 11, in <module> load_entry_point('examples-rclpy-minimal-action-server==0.6.1', 'console_scripts', 'server')() File "/home/jacob/ws/actions_ws/install/examples_rclpy_minimal_action_server/lib/python3.5/site-packages/examples_rclpy_minimal_action_server/server.py", line 103, in main rclpy.spin(minimal_action_server, executor=executor) File "/home/jacob/ws/actions_ws/install/rclpy/lib/python3.5/site-packages/rclpy/__init__.py", line 119, in spin executor.spin_once() File "/home/jacob/ws/actions_ws/install/rclpy/lib/python3.5/site-packages/rclpy/executors.py", line 573, in spin_once raise handler.exception() File "/home/jacob/ws/actions_ws/install/rclpy/lib/python3.5/site-packages/rclpy/task.py", line 207, in __call__ self._handler.send(None) File "/home/jacob/ws/actions_ws/install/rclpy/lib/python3.5/site-packages/rclpy/action/server.py", line 323, in _execute_goal execute_result = await await_or_execute(execute_callback, goal_handle) File "/home/jacob/ws/actions_ws/install/rclpy/lib/python3.5/site-packages/rclpy/executors.py", line 89, in await_or_execute return await callback(*args) File "/home/jacob/ws/actions_ws/install/examples_rclpy_minimal_action_server/lib/python3.5/site-packages/examples_rclpy_minimal_action_server/server.py", line 80, in execute_callback await asyncio.sleep(1) File "/usr/lib/python3.5/asyncio/tasks.py", line 516, in sleep return (yield from future) File "/usr/lib/python3.5/asyncio/futures.py", line 362, in __iter__ assert self.done(), "yield from wasn't used with future" AssertionError: yield from wasn't used with future

I'll see if I can figure out what's gone wrong.

This looks like me being wrong about what asyncio.sleep() expects. https://github.com/python/cpython/blob/6b0d50d92e80faaed8a043e6554ccb5d046114a5/Lib/asyncio/tasks.py#L517-L532

Looks like it needs an asyncio event loop. You can ignore my comments about using it

I see.
I can reproduce the same issue with a Service server as well. It seems like something rclpy should be able to handle though, so I've opened an issue ros2/rclpy#279.

sloretz · 2019-03-04T23:28:26Z

rclpy/actions/minimal_action_server/examples_rclpy_minimal_action_server/server.py

+    minimal_action_server = MinimalActionServer()
+
+    # Use a MultiThreadedExecutor to enable processing goals concurrently
+    executor = MultiThreadedExecutor()


I would expect a single threaded executor to be ok if using asyncio.sleep() above.

rclpy/actions/minimal_action_server/package.xml

- Fix comment - Add author tag to package.xml Signed-off-by: Jacob Perron <jacob@openrobotics.org>

jacobperron added the in progress Actively being worked on (Kanban column) label Jan 9, 2019

jacobperron mentioned this pull request Jan 9, 2019

Action implementation ros2/rclpy#257

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jacobperron self-assigned this Jan 9, 2019

jacobperron mentioned this pull request Jan 10, 2019

Actions ros2/ros2#583

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sloretz reviewed Jan 29, 2019

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rclpy/actions/minimal_action_client/client_not_composable.py Outdated Show resolved Hide resolved

jacobperron added in review Waiting for review (Kanban column) and removed in progress Actively being worked on (Kanban column) labels Jan 29, 2019

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sloretz mentioned this pull request Feb 2, 2019

Make examples install entry point scripts into a package #226

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jacobperron mentioned this pull request Feb 6, 2019

Crystal Patch Release 2 ros2/ros2#647

Closed

jacobperron added 14 commits February 7, 2019 09:18

Copy rclpy action examples from #216

a93e25c

Bump version of examples_rclpy_action to match other packages

4194f2c

Consolidate composable action client example

8c7c564

Add action client example that is not composable

7226b87

Wait for action server

0333797

Restructure into separate packages for action client and action serve…

c55a413

…r examples This package structure is consistent with examples for services and topics.

Update API in action server examples

a5b067d

Rename action server examples

6f5246e

Now the 'simplest' example is 'server.py'.

Add action server example that is not composable

0e48b86

Update setup.py

32a5caf

Fix syntax

0173b2c

Update action client examples to use goal handle API for the result

0a41589

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Improve action client output and result handling

6095a0e

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Update action server examples

32ea3b6

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

jacobperron force-pushed the rclpy_action_examples branch from 1119b27 to 32ea3b6 Compare February 7, 2019 20:10

jacobperron added 2 commits February 7, 2019 14:20

Move action examples into Python packages

e7917a3

This avoid top-level module names from clashing when installed. Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Add action client cancel example

5216ba9

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

sloretz reviewed Feb 11, 2019

View reviewed changes

jacobperron added 6 commits February 12, 2019 17:59

Address review comments

502a8c6

* Update author * Update copyright year * Shutdown client example after result received Signed-off-by: Jacob Perron <jacob@openrobotics.org>

GoalResponse.ACCEPT_AND_EXECUTE -> GoalResponse.ACCEPT

45bde23

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Fix client_cancel example

ce7bb67

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Remove race from server_single_goal example

b0c739a

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Add action server example that defers the execution of an accepted goal

e68a577

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Reduce the timer period for the client cancel example

0ea84a0

This makes it easy to experiment with the scenario where a deferred goal is canceled prior to execution. Signed-off-by: Jacob Perron <jacob@openrobotics.org>

jacobperron mentioned this pull request Feb 14, 2019

Add ActionServer ros2/rclpy#270

Merged

jacobperron added 2 commits February 13, 2019 17:45

Support canceling goals with non-composable action server example

240e7ab

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

Add action server example that queues goals

eec2b79

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

sloretz reviewed Mar 4, 2019

View reviewed changes

Address review

dfd71ad

- Fix comment - Add author tag to package.xml Signed-off-by: Jacob Perron <jacob@openrobotics.org>

sloretz approved these changes Mar 5, 2019

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jacobperron merged commit cfc9bc6 into master Mar 5, 2019

jacobperron deleted the rclpy_action_examples branch March 5, 2019 18:11

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jacobperron mentioned this pull request Mar 7, 2019

Backport Python Action examples to Crystal #229

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nuclearsandwich mentioned this pull request Mar 8, 2019

Crystal Patch Release 3 ros2/ros2#656

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rclpy action examples #222

rclpy action examples #222

jacobperron commented Jan 9, 2019

sloretz commented Feb 2, 2019

jacobperron commented Feb 7, 2019 •

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rclpy action examples #222

rclpy action examples #222

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jacobperron commented Feb 7, 2019 •

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