Node constructor annotations are too opaque about launch_ros

[deitry]

This is what I get as help tooltip in my IDE (VS Code):

class LifecycleNode(node_name: Text, package: SomeSubstitutionsType, node_executable: SomeSubstitutionsType, node_namespace: Optional[SomeSubstitutionsType]=None, parameters: Optional[SomeParameters]=None, remappings: Optional[SomeRemapRules]=None, arguments: Optional[Iterable[SomeSubstitutionsType]]=None, name: Optional[SomeSubstitutionsType]=None, cwd: Optional[SomeSubstitutionsType]=None, env: Optional[Dict[SomeSubstitutionsType, SomeSubstitutionsType]]=None, additional_env: Optional[Dict[SomeSubstitutionsType, SomeSubstitutionsType]]=None, shell: bool=False, sigterm_timeout: SomeSubstitutionsType=LaunchConfiguration(
            'sigterm_timeout', default=5), sigkill_timeout: SomeSubstitutionsType=LaunchConfiguration(
            'sigkill_timeout', default=5), prefix: Optional[SomeSubstitutionsType]=None, output: Text='log', output_format: Text='[{this.name}] {line}', log_cmd: bool=False, on_exit: Optional[Union[
            SomeActionsType,
            Callable[[ProcessExited, LaunchContext], Optional[SomeActionsType]]
        ]]=None, condition: Optional[Condition]=None)
Action that executes a ROS lifecycle node.

As ROS2 user, I can't say your way is stricly better since it's easier to look at source file instead of getting through verbosity of your approach. It seems to me that both ways are not good enough to get real help from them.

I guess the real problem is lack of examples that would cover all the features of some technology like launch system - in one place. Or better - centralized feature-full documentation instead of piles of design articles, Q&A, Github issues and so on.

[mabelzhang]

Thank you for the suggestions! Feel free to open a PR to improve the help message.

On a side note, we are currently actively working on a set of tutorials for ROS 2 to improve the user and developer experience. Keep an eye out :)

[rotu]

@mabelzhang This seems like low-hanging fruit to improve the user and developer experience. I wrote it up as a github issue so you guys could easily implement it.

[dirk-thomas]

This seems like low-hanging fruit to improve the user and developer experience. I wrote it up as a github issue so you guys could easily implement it.

@rotu If it can be so easily implemented please consider to create a pull request for it.

[rotu]

@dirk-thomas because I thought someone with more familiarity and insight into the codebase would be a better fit for this development. I.e. less likely to make dumb mistakes. It would take a maintainer as long to review the code as to code it up in the first place

[rotu]

ros/rosdistro#22535
I tried to start on this PR and I just don't think I can deal with this dependency hell in using a simple PIP library >.<. I'm just too frustrated with the ROS way of doing Python to fix this issue myself. :-(