Added ROS2 ActionClient w/ limited functionality

[danmartzla]

Added the roslibpy.ActionClient object to send actions goals to ROS2-based systems.
This implementation has limited capabilities (related to RobotWebTools/rosbridge_suite#909) such as:

• Goal cancelation is not functional.
• Goal rejection/acceptance are not being notified to the Action client.

What type of change is this?

• Bug fix in a backwards-compatible manner.
• New feature in a backwards-compatible manner.
• Breaking change: bug fix or new feature that involve incompatible API changes.
• Other (e.g. doc update, configuration, etc)

Checklist

• I added a line to the CHANGELOG.rst file in the Unreleased section under the most fitting heading (e.g. Added, Changed, Removed).
• I ran all tests on my computer and it's all green (i.e. invoke test).
• I ran lint on my computer and there are no errors (i.e. invoke check).
• I have added tests that prove my fix is effective or that my feature works.
• I have added necessary documentation (if appropriate)

[sea-bass]

This all looks great to me -- just a few minor formatting things and I think this V1 support will be a great addition. Thank you!

[danmartzla]

This all looks great to me -- just a few minor formatting things and I think this V1 support will be a great addition. Thank you!

Hi! I already fixed your suggested minor changes. Thanks.

[sea-bass]

Sorry, but I'm not a maintainer of this repo so I can't actually approve your changes. I was just looking because I implemented the rosbridge side of this work.

[sea-bass]

Sorry @danmartzla, I forgot to mention that I recently landed a small change to the protocol that allows for cleaner action cancellation. It may require a small change since now the action_result message also contains a status field telling you whether the action was successful, canceled, aborted, etc.: RobotWebTools/rosbridge_suite#953

Also @gonzalocasas Would you be able to review this PR?

[danmartzla]

I've adapted this minor change to work with the latest rosbridge_suite updates.

However, sending a cancelation request from a roslibpy "Action Client" seems not to be working. The "rosbridge_server" debug logs do not report any cancelation request (or any other received message). The JSON message seems to be correct based on the documentation:

https://github.com/danmartzla/roslibpy/blob/bcd403c12f32da1118a6c71d84602a237592bf72/src/roslibpy/core.py#L598-L604

[sea-bass]

It does look right... I wonder if you need the send_action_goals_in_new_thread parameter in the server set to True for this to work?

[danmartzla]

It does look right... I wonder if you need the send_action_goals_in_new_thread parameter in the server set to True for this to work?

OK. I was totally unaware about this parameter of the "rosbridge_server". I can confirm that it is working well when launching the server this way:
ros2 launch rosbridge_server rosbridge_websocket_launch.xml send_action_goals_in_new_thread:="true"

I'm adding this as a comment in the example code : https://github.com/danmartzla/roslibpy/blob/13ae184e691f3024c15bcc1e6a3f857c89affb65/docs/files/ros2-action-client.py#L41-L42

[sea-bass]

Awesome, great to hear!

There is also an equivalent call_services_in_new_thread which allows multiple service calls to be processed concurrently.

Not necessary for this example, of course, but just noting.

[sea-bass]

@gonzalocasas this has been around a while and seems to work well. Please consider merging this great contribution.

[yuriyfedyuk]

@danmartzla First of all thank you for such great feature. During the testing we faced the same issue that you had, we are not able to cancel action. We use ROS2 humble and we build rosbridge and roslibpy from the latest sources.
Here is how we launch rosbridge server
root@9db9713f3160:/opt/ros_ws# ros2 launch rosbridge_server rosbridge_websocket_launch.xml send_action_goals_in_new_thread:=true [INFO] [launch]: All log files can be found below /root/.ros/log/2025-02-01-19-31-13-527917-9db9713f3160-34804 [INFO] [launch]: Default logging verbosity is set to INFO [INFO] [rosbridge_websocket-1]: process started with pid [34805] [INFO] [rosapi_node-2]: process started with pid [34807] [rosbridge_websocket-1] [WARN] [1738438274.037011958] [rosbridge_websocket]: The 'default_call_service_timeout' parameter is currently set to 0.0, which means service calls will block indefinitely if no response is received. Please note that in the Jazzy and later releases, the default value for this parameter will be updated to 5.0 seconds. [rosbridge_websocket-1] [WARN] [1738438274.037679806] [rosbridge_websocket]: The 'call_services_in_new_thread' parameter is currently set to False, which means service calls will block the main thread. Please note that in the Jazzy and later releases, the default value for this parameter will be updated to True. [rosbridge_websocket-1] [INFO] [1738438274.040429291] [rosbridge_websocket]: Rosbridge WebSocket server started on port 9090

@danmartzla @sea-bass Could you please describe your environment? do you use humble or newest version?

[yuriyfedyuk]

Yes, I’m running the command, so this is strange to me why I can see this issue. ros2 launch rosbridge_server rosbridge_websocket_launch.xml send_action_goals_in_new_thread:=trueI can confirm that without flag I see the warning in the log related to action goals2 лют. 2025 р. о 15:50 Sebastian Castro ***@***.***> пише: @yuriyfedyuk did you try this? #125 (comment) In the latest version of rosbridge you even get a warning in the logger about this, as is included in your question. —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you were mentioned.Message ID: ***@***.***>

[sea-bass]

@yuriyfedyuk Asking just in case, but is the action server that you're communicating to via rosbridge capable of handling cancellations? If it is not, then sending a cancel message via rosbridge will do nothing.

Have you tried with e.g., this server?
https://github.com/ros2/examples/blob/rolling/rclpy/actions/minimal_action_server/examples_rclpy_minimal_action_server/server_single_goal.py

[yuriyfedyuk]

Thank you, that was the case. I've used default fibonacci action server, and I wasn't aware that it can't be cancelled. Using action server from your link did the trick and action can be cancelled. We will continue testing, and looking forward to have it merged пн, 3 лют. 2025 р. о 06:14 Sebastian Castro ***@***.***> пише:

…

@yuriyfedyuk <https://github.com/yuriyfedyuk> Asking just in case, but is the action server that you're communicating to via rosbridge capable of handling cancellations? If it is not, then sending a cancel message via rosbridge will do nothing. Have you tried with e.g., this server? https://github.com/ros2/examples/blob/rolling/rclpy/actions/minimal_action_server/examples_rclpy_minimal_action_server/server_single_goal.py — Reply to this email directly, view it on GitHub <#125 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABDCLHXGVWRSUP5O3R4QYBT2N3ULZAVCNFSM6AAAAABKEBJ4JCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDMMRZHA3DQOBZGY> . You are receiving this because you were mentioned.Message ID: ***@***.***>

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