Some examples of ROS 2 launch files in Python, XML, and YAML.
The launch files arg_examples.launch.py, arg_examples.launch.xml, and arg_examples.launch.yaml show off some features
of argument declaration.
These were developed to try to understand ros2/launch#698
They simply declare and print a set of arguments.
Run (with .py, .xml, or, yaml in place of <extension>):
ros2 launch dz_launch_examples arg_examples.launch.<extension> simple_arg:=<some value>
The Python version also demonstrates:
- Iteration over a launch context's configuration to get the names and values of declared launch arguments
- Use of
launch.actions.LogInfoto log information from the log file.
To see the declared arguments and their descriptions and valid choices, run:
ros2 launch dz_launch_examples arg_examples.launch.<extension> --show-args
This provides an example of returning several talker/listener node pairs in consecutively numbered namespaces, inspired by this post.
To launch three node pairs, for example, run:
ros2 launch dz_launch_examples opaque_multi_nodes.launch.py num_node_pairs:=3