Replaced numbers with SystemDefaultsQos()

[Shobuj-Paul]

Description

This PR replaces "magic numbers" with SystemDefaultsQos(), making it more readable and possibly more stable.
Fixes #2225

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[codecov]

Codecov Report

Patch coverage: 35.72% and project coverage change: +0.01% 🎉

Comparison is base (830ceda) 50.50% compared to head (3d96f76) 50.50%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2271      +/-   ##
==========================================
+ Coverage   50.50%   50.50%   +0.01%     
==========================================
  Files         386      386              
  Lines       31732    31736       +4     
==========================================
+ Hits        16023    16026       +3     
- Misses      15709    15710       +1     

Files Changed	Coverage Δ
...g/rdf_loader/src/synchronized_string_parameter.cpp	32.31% <0.00%> (-0.50%)	⬇️
...it_ros/robot_interaction/src/robot_interaction.cpp	0.00% <0.00%> (ø)
...obot_state_rviz_plugin/src/robot_state_display.cpp	0.00% <0.00%> (ø)
...ugin_render_tools/src/trajectory_visualization.cpp	0.00% <0.00%> (ø)
...nning_scene_monitor/src/planning_scene_monitor.cpp	45.44% <66.67%> (+0.18%)	⬆️
...or/src/current_state_monitor_middleware_handle.cpp	88.89% <100.00%> (ø)

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[sjahr]

Thanks for starting this @Shobuj-Paul. Ping me once the PR is ready for review!

[sjahr]

This looks good so far

[Shobuj-Paul]

Hi @sjahr
Can I leave instances such as this untouched? This seems to be more explanatory than just a number.

[sjahr]

Hi @sjahr Can I leave instances such as this untouched? This seems to be more explanatory than just a number.

Good question 🤔 Can you add a comment to explain this choice (if you know it)? Otherwise just add a TODO(): ? comment to mark it and we'll figure it out in the review of this PR. @tylerjw Do you know this?

[Shobuj-Paul]

Hi @sjahr Can I leave instances such as this untouched? This seems to be more explanatory than just a number.

Good question thinking Can you add a comment to explain this choice (if you know it)? Otherwise just add a TODO(): ? comment to mark it and we'll figure it out in the review of this PR. @tylerjw Do you know this?

Understood, I shall comment on all such instances.

[Shobuj-Paul]

@sjahr
This PR is ready for review. Couple of things left to be confirmed during review:

• Documenting a reason for giving this kind of QoS profile.
• For python nodes, I couldn't find any equivalent of SystemDefaultsQoS(), so if there a better way of increasing readability of instances like these?

[sjahr]

I think this looks good so far 👍 Thank you! I'll approve it once we've got an answer regarding rclcpp::QoS(1).transient_local().reliable()

[sjahr]

I think you can explicitly set it via https://docs.ros2.org/foxy/api/rclpy/api/qos.html but if you just don't set it like in the tutorial, it seems to default to the system default. Can you check if that works? @peterdavidfagan Do you have any advice here?

[Shobuj-Paul]

I think you can explicitly set it via https://docs.ros2.org/foxy/api/rclpy/api/qos.html but if you just don't set it like in the tutorial, it seems to default to the system default. Can you check if that works? @peterdavidfagan Do you have any advice here?

Yep, this looks good. I'll leave the python nodes as they are for now, since this kind of depth setting seems to be documented.

[tylerjw]

This is a good cleanup. Thank you!