[Spawner] Allow parsing the parameter files parsed from spawner to controllers

[saikishor]

Fixes #3135
Tested with ros-controls/ros2_control_demos#1079

@urfeex FYI

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.34%. Comparing base (152ed06) to head (add57bd).
⚠️ Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
controller_manager/controller_manager/spawner.py	80.00%	2 Missing and 3 partials ⚠️
controller_manager/test/test_advanced_spawner.cpp	91.66%	0 Missing and 1 partial ⚠️
controller_manager/test/test_spawner_unspawner.cpp	91.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3136      +/-   ##
==========================================
- Coverage   89.35%   89.34%   -0.01%     
==========================================
  Files         158      158              
  Lines       19392    19441      +49     
  Branches     1573     1583      +10     
==========================================
+ Hits        17327    17369      +42     
- Misses       1419     1421       +2     
- Partials      646      651       +5     

Flag	Coverage Δ
unittests	89.34% <85.71%> (-0.01%)	⬇️

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Files with missing lines	Coverage Δ
controller_manager/test/test_advanced_spawner.cpp	94.68% <91.66%> (-0.14%)	⬇️
controller_manager/test/test_spawner_unspawner.cpp	96.00% <91.66%> (-0.13%)	⬇️
controller_manager/controller_manager/spawner.py	73.20% <80.00%> (+0.70%)	⬆️

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[fmauch]

I have to say that I find it mildly confusing that --ros-args --params-file <filename> != --param-file <filename>.

Maybe it would be worth mentioning explicitly, that --param-file can be replaced by --ros-args --params-file or more importantly that in a launchfile

                arguments=[
                    "my_controller_name",
                    "--param-file",
                    PathSubstitution(FindPackageShare("my_config_pkg"))
                    / "config"
                    / "controllers.yaml",
                ],

can be written as

                parameters=[
                    ParameterFile(
                        PathSubstitution(FindPackageShare("my_config_pkg"))
                        / "config"
                        / "controllers.yaml",
                    ),
                ],
                arguments=[
                    "my_controller_name",
                ],

Or maybe put more simply: Controller parameters can either be specified by loading a parameter file using --param file or through the spawner's ROS node parameters when running as a ROS node.

But this PR definitively solves my issue.

[saikishor]

I have to say that I find it mildly confusing that --ros-args --params-file <filename> != --param-file <filename>.

Maybe it would be worth mentioning explicitly, that --param-file can be replaced by --ros-args --params-file or more importantly that in a launchfile

                arguments=[
                    "my_controller_name",
                    "--param-file",
                    PathSubstitution(FindPackageShare("my_config_pkg"))
                    / "config"
                    / "controllers.yaml",
                ],

can be written as

                parameters=[
                    ParameterFile(
                        PathSubstitution(FindPackageShare("my_config_pkg"))
                        / "config"
                        / "controllers.yaml",
                    ),
                ],
                arguments=[
                    "my_controller_name",
                ],

Or maybe put more simply: Controller parameters can either be specified by loading a parameter file using --param file or through the spawner's ROS node parameters when running as a ROS node.

But this PR definitively solves my issue.

I'll try to update the docs tonight. However, I think it is better I don't say it generic that --param-file can be replaced by this, just because then when you try to load multiple controllers with multiple param files with some wildcard entries, it won't work.

Thank you for testing it 👏🏾

[christophfroehlich]

LGTM, thanks!