roslaunch2 is a (pure Python based) ROS package that facilitates writing versatile, flexible and dynamic launch configurations for the Robot Operating System (ROS 1) using Python, both for simulation and real hardware setups, as contrasted with the existing XML based launch file system of ROS, namely roslaunch. Note that roslaunch2 is not (yet) designed and developed for ROS 2 but for ROS 1 only although it may also inspire the development (of the launch system) of ROS 2. It is compatible with all ROS versions providing roslaunch which is used as its backend. roslaunch2 has been tested and used on ROS Indigo, Jade, Kinetic, Lunar, Melodic, and Noetic; it also supports a “dry-mode” to generate launch files without ROS being installed at all. The key features of roslaunch2 are
- versatile control structures (conditionals, loops),
- extended support for launching and querying information remotely,
- an easy-to-use API for also launching from Python based ROS nodes dynamically, as well as
- basic load balancing capabilities for simulation setups.
More information and detailed examples can be found in the "roslaunch2: Versatile, Flexible and Dynamic Launch Configurations for the Robot Operating System" chapter of the "Robot Operating System (ROS): The Complete Reference" book (volume 4) published by Springer. Please cite it (see below), if you find roslaunch2 useful for your work.
Installing the roslaunch2 package is straightforward and equal to installing any other ROS package from source / GitHub.
- Assuming, you already have a catkin workspace (see here how to setup one), change to that workspace's source directory:
cd ~/catkin_ws/src - Now, clone this repository to that
srcdirectory:git clone https://github.com/CodeFinder2/roslaunch2.git - The package should be usable now. If not, run
catkin_makeonce and ensure that the workspace is sourced in your shell.
For more information, see also:
The following code shows a small working example that launches the 'fake_localization' node if installed (taken from the example of the aforementioned chapter).
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from roslaunch2 import *
def main(**kwargs): # contains the entire code to launch
cfg = Launch() # root object of the launch hierarchy
# Process arguments (not command line arguments) for this launch module:
ns = kwargs['namespace'] if 'namespace' in kwargs else str()
g = Group(ns) # possibly empty namespace group
# Create a (cached) package reference:
pkg = Package('fake_localization', True)
if pkg and pkg.has_node('fake_localization', True): # only add if it exists
n = Node(pkg)
Helpers.enable_gdb(n) # if you want to debug this node
# Set coodinate frame IDs (on the ROS parameter server):
n += ServerParameter('global_frame_id', 'map')
n += ServerParameter('odom_frame_id', tf_join(ns, 'odom'))
n += ServerParameter('base_frame_id', tf_join(ns, 'base_link'))
g += n # move node to namespace 'ns'
cfg += g
return cfgYou can run it with:
$ roslaunch2 roslaunch2 rl2-example.pylAs you can see from the example, there must be a function called main(**kwargs) which defines what to launch. When a launch module is included (reused), this function (also) specifies what is included. The function must return an instance of theroslaunch2.launch.Launch class which defines the hierarchy (nodes, parameters, namespaces, etc.) to be launched. Command line flags should be consumed using the roslaunch2.parameter.LaunchParameter class. When including launch files, it is also possible to pass parameters to the included launch module using kwargs. However, it is up to the included launch module to process/favour such parameters appropriately. roslaunch2.parameter.ServerParameter and roslaunch2.parameter.FileParameter must be used to specifiy parameters for nodes (represented as roslaunch2.node.Node).
Your Python launch code must be saved in a file with the extension .pyl (e. g., my_launch.pyl) which should be placed in the launch directory of some ROS package (e. g., my_ros_package). As shown in the previous example, it can then be launched with:
$ roslaunch2 my_ros_package my_launch.pylA minimal working example (MWE) is therefore given by
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import roslaunch2.launch
def main(**kwargs):
return roslaunch2.launch.Launch()which just starts a roscore.
You may also want to have a look at the complete API/code documentation and the FAQ.
Setting up a systemd deamon (Ubuntu >= v15.10) for Pyro and the roslaunch2 server is described here. This guide describes how to use upstart (Ubuntu < v15.10) to automatically run the Pyro name server and the roslaunch2 server on boot.
To enable tab completion support, you need to source the file roslaunch2/config/roslaunch2_auto_completion.bash.
The entire code is BSD 3-Clause licenced, see here. Thus, you can modifiy it, use it privately and commercially but you must retain a license and copyright notice when doing so. If you find this package useful, please star this repo and/or cite the aforementioned book chapter with:
@INBOOK{Boeckenkamp2020,
author = {B{\"o}ckenkamp, Adrian},
title = {{roslaunch2: Versatile, Flexible and Dynamic Launch Configurations for the Robot Operating System}},
editor = {Koubaa, Anis},
booktitle = {Robot Operating System (ROS): The Complete Reference},
publisher = {Springer International Publishing},
address = {Heidelberg},
year = 2020,
volume = 4,
pages = {165--181},
isbn = {978-3-030-20190-6},
doi = {10.1007/978-3-030-20190-6_7},
url = {https://doi.org/10.1007/978-3-030-20190-6_7},
note = {https://link.springer.com/chapter/10.1007/978-3-030-20190-6_7}
}
Copyright (c) 2017-2020, Adrian Böckenkamp, Department of Computer Science VII, TU Dortmund University.
All rights reserved.
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