Added ros_ign_gazebo for ros2

[ahcorde]

This package contains things that make it convenient to integrate ROS with Ignition, such as:

• Launch files
• ROS-enabled executables

Run ignition Gazebo

ros2 launch ros_ign_gazebo ign_gazebo.launch.py ignition_args:="shapes.sdf"

# or

ros2 launch ros_ign_gazebo ign_gazebo_gui.launch.py 
ros2 launch ros_ign_gazebo ign_gazebo_server.launch.py ignition_args:="shapes.sdf"

ros2 run ros_ign_gazebo ign_gazebo shapes.sdf

Spawn entities

ros2 run ros_ign_gazebo create -world default -file 'https://fuel.ignitionrobotics.org/1.0/openrobotics/models/Gazebo'

By the way this command is adding the entity to ignition gazebo, but the mesh doesn't appear.

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Note: I created the branch ros2 to keep it as the devel branch.

Signed-off-by: ahcorde ahcorde@gmail.com

[chapulina]

Thanks for tackling this so quickly, @ahcorde ! I tried it with Eloquent and it worked for me. It would be nice to document the supported versions on the README. Also, I'm not sure why Travis wasn't triggered 🧐 I see that it's supposed to install dashing.

I created the branch ros2 to keep it as the devel branch.

Would that be for eloquent and foxy?. Could we target this PR at dashing? Usually on Ignition we target PRs at the lowest compatible version and merge changes forward (as opposed to how on ROS commits are cherry-picked backwards).

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Some other requests that could come in follow-up PRs:

• Could you add the package to ros_ign/package.xml?
• Can we use the new launch file on ros_ign_gazebo_demos? We should still leave the existing one there for a while in case someone is using it, but we shouldn't encourage its use anymore.

[chapulina]

Everything is working for me, I'd just like to hear your thoughts about:

• not splitting gui / server launch files
• not using a bash script

[ahcorde]

not splitting gui / server launch files

I don't have a strong opinion here. I created two launch files just to keep the same idea that we have in Gazebo and provide a launch file to run ign-gazebo headless mode (without reviewing/knowing the arguments).

But Gazebo is a different case where we have two executables in Ignition we only have one. The idea of duplicate the arguments sounds weird and it's going to create issues in the user side.

I think is a good idea to handle everything in the same launch file.

not using a bash script

the bash script is not adding any value I can remove it

[chapulina]

I'm not sure why Travis wasn't triggered

This org hadn't granted permissions. There's a build running now: https://travis-ci.org/github/ignitionrobotics/ros_ign/builds/698585638

[chapulina]

I skipped one more key on CI in 9d8ab84 and fixed some linters on 26025a3. I think this is good to merge if Travis comes back green.