LaunchConfiguration is not read from ComposableNode when included inside a group action

[stevedanomodolor]

Bug report

Required Info:

• Operating System:
  • Ubuntu 22.04.1 LTS
• Installation type:
  • source -> ros2
• Version or commit hash:
• DDS implementation:
• Client library (if applicable):
  • ros2 rolling -> nav2
• Related issue
• Use SetParameter Launch API to set the yaml filename for map_server ros-navigation/navigation2#3174

Steps to reproduce issue

ComposableNode(
                        condition=LaunchConfigurationNotEquals('map', ''),
                        package='nav2_map_server',
                        plugin='nav2_map_server::MapServer',
                        name='map_server',
                        parameters=[configured_params, {'yaml_filename': map_yaml_file}],
                        remappings=remappings
                        ),
ComposableNode(
                        condition=LaunchConfigurationNotEquals('map', ''),
                        package='nav2_map_server',
                        plugin='nav2_map_server::MapServer',
                        name='map_server',
                        parameters=[configured_params, {'yaml_filename': map_yaml_file}],
                        remappings=remappings
                        ),

Expected behavior

It should pay attention to the condition but executes both composable node. The issue #114 should have fixed it but seems not to have.

Actual behavior

It does not pay attention to the condition at all and executes both composablenode

Additional information

---

Feature request

Feature description

Implementation considerations

[clalancette]

So we do have tests to ensure that condition works in a ComposableNode with IfCondition and UnlessCondition:

• launch_ros/test_launch_ros/test/test_launch_ros/actions/test_composable_node_container.py

  Line 165 in 73098cf

  condition=UnlessCondition(LaunchConfiguration('flag'))

• launch_ros/test_launch_ros/test/test_launch_ros/actions/test_composable_node_container.py

  Line 172 in 73098cf

  condition=IfCondition(LaunchConfiguration('flag'))

So I'm somewhat confident the basic functionality works.

That said, we don't have tests for LaunchConfigurationNotEquals with ComposableNode. I don't even know if it is supposed to work. Pinging @adityapande-1995 @jacobperron @hidmic for thoughts.

[methylDragon]

Well..., two things:

The LaunchConfigurationEquals and LaunchConfigurationNotEquals conditions are pretty recently deprecated.

Also, weird things happen when trying to check for equality with empty strings with that condition..

Try with the EqualsSubstitution instead!
https://github.com/ros2/launch/blob/rolling/launch/launch/conditions/launch_configuration_equals.py

e.g.:

IfCondition(EqualsSubstitution(LaunchConfiguration('some_launch_arg'), "some_equality_check")

If that fails, try the more terse conditions as suggested by Chris, above.

[stevedanomodolor]

How do i upgrade the launch package to have this changes, it seems that this feature was added not recently. I am using ros2 rolling. @methylDragon

[methylDragon]

Try

sudo apt update
sudo apt upgrade --only-upgrade ros-rolling-launch

[stevedanomodolor]

I get this when I try to upgrade, is this feature available in ros-rolling yet?

root@stevedan-OMEN-Laptop-15-ek0xxx:/opt/ros/rolling/lib/python3.10/site-packages/launch/substitutions# sudo apt-get install --only-upgrade ros-rolling-launch
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
ros-rolling-launch is already the newest version (1.2.0-1jammy.20220914.023741).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
root@stevedan-OMEN-Laptop-15-ek0xxx:/opt/ros/rolling/lib/python3.10/site-packages/launch/substitutions# ls
__init__.py              environment_variable.py    python_expression.py
__pycache__              find_executable.py         substitution_failure.py
anon_name.py             launch_configuration.py    text_substitution.py
boolean_substitution.py  local_substitution.py      this_launch_file.py
command.py               path_join_substitution.py  this_launch_file_dir.py
root@stevedan-OMEN-Laptop-15-ek0xxx:/opt/ros/rolling/lib/python3.10/site-packages/launch/substitutions# 

[methylDragon]

Hmm, you're right. The update was released 5 days ago, but it might take a little while for it to get through to the main repos. It should come out soon though.

[hodnajit]

I am facing the similar issue, but I am using IfCondition. You may find the issue description here:
#335

[methylDragon]

I am facing the similar issue, but I am using IfCondition. You may find the issue description here: #335

I think the issue is related. I am going to put some time into investigating this...

[methylDragon]

Hello! This PR should address the issue (:

• Ensure load_composable_nodes respects condition #339

Do note that it'll take a little while for this change to propagate through and get released (the PR will need to get merged, then the repo has to get released, and finally there has to be a rolling sync.) So I'd recommend building from source if you want the change immediately.
@stevedanomodolor

[stevedanomodolor]

Thanks for the update

[SteveMacenski]

Changes being made now in Nav2 https://github.com/ros-planning/navigation2/pull/3445/files

I'll say that having to replace LaunchConfigurationEquals with IfCondition(EqualsSubstitution(LaunchConfiguration())) seems to be moving in the wrong direction in launch of making it all increasingly obtuse, not simpler. I'm not exactly sure why a method to wrap that logic called LaunchConfigurationEquals was depreciated. It is a useful shorthand of a common desire to check the value of a launch configuration provided on the commandline. All 3 of those actions should definitely exist, but the method making it easier to use it seems useful.