I started to experiment with navigation2 and especialy the BT part for more complex behaviors and recoveries. It somehow expected to also find a debug and visualization tool, but so far I couldn’t find one. Groot does not work directly, so I wanted to know if there are plans to make it usable or how other developers use BTs in ROS2
There is an open PR working on this: https://github.com/ros-planning/navigation2/pull/1958
Hi,
my ability to support Groot is limited and usually I prioritize my open source projects based on the feeling of their usefulness to the community. I was not sure about how many people where actually using Groot.
I was not aware of the open issue in navigation2… interesting to know.
I haven’t maintained much this part. If you find any actual bug, let me know.
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Hey there… 
Cool to see my PR spotted.
I’m currently stuck on 2 things:
That the Groot PR (mentioned by me in this PR above) including my PR of this Groot PR gets accepted by @facontidavide . That way reloading of the BT does not crash Groot… 
I just extended the PR for this a little bit, this way I was not able to manually crash it with random connects / disconnects / reset of Nav2 lifecycle nodes etc.
The second thing is CI:
I went a little bit too far down the rabbit hole and got confused why there is ros2/launch and ros2/ros_launch …
What I want to implement is testing with the optional parameter “enable_groot_monitoring” while not creating a new complete param file of the nav2 parameters…
So basically substituting this one paramerter with the value “True” while keeping the rest of the params.yaml untouched. = With existing ROS2 tools. #helpwanted !! @mikeferguson ? 
(Alternatively fixing the original nav2-thing for this: https://github.com/ros-planning/navigation2/blob/main/nav2_common/nav2_common/launch/rewritten_yaml.py )
Also, documentation for how to use Groot with nav2 is happening this weekend. (not hard at all )
So the PR is sort of ready, just need to add the nice last bits.
Also @NikolasE are you already in the navigation2 slack? Would be cool to know what you are up to with BTs!
Merged. Better late than never.
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Hey,
Thanks! There are just some small fixes missing. I put them all together in https://github.com/BehaviorTree/Groot/pull/96
@facontidavide Would be cool if you could merge this as well. I took the earlier file conflicts of #61 into account and retested it with nav2:main .
On the launch_file param substitution:
I found the root cause.The rewritten_yaml.py works fine, but only for 1-dimensional dicts and not
params = {'bt_navigator':{'ros__parameters':{'enable_groot_monitoring' : 'True'}}}
If I use this, the value for ‘bt_navigator’ gets completely replaced with just ‘ros__parameters’ as a value and not the rest of the multi-dimensional dict. I’m currently thinkering on this issue… maybe somebody else has a hint or something completely else that gets the job done?
Maybe @wjwwood, do you know something/someone that could help here?
(tl;dr Rest of the issue is mentioned in my previous post, the CI section)
Cheers,
Florian
Update:
CI / YAML Parameter Substitution user-“bug”: I found it 
I was to focused on getting the multi-dimensional key as an Input of RewrittenYaml()… But, RewrittenYaml has a recursive iterator built-in that searches for the key on any level of the yaml-params dict… 
But this happens only when the sub-function perform(context) with a given LaunchContext is triggered, which did not happen in the existing CI tests I skimmed through…
@smac probably also interesting for you - will be included in the PR and probably worth some docu as well.
Looks like this PR is getting finished soon… 
Hey @facontidavide,
just a friendly ping!
As my PR of nav2 and its documentation are slowly reaching a finish line, it would be cool if you have a moment to merge my PR for Groot!
Thank you!
Cheers