pyros-setup 0.2.1

Toolsuite for running ROS environments directly from python code, without any specific requirements outside of usual python

Toolsuite for running ROS environments directly from python code, without any specific requirements outside of usual python.

This is a pure python package, to be installed in your system, in order to allow easy ROS access from your python environment.

HowTo install

To install it:

pip install pyros_setup

You need to be careful which environmnt you install this package in:

• If you are running in a virtual environment myvenv, and you want to access ROS packages outside this environment (since they should be installed on the system in /opt/ros/$ROS_DISTRO), you need to install pyros-setup in the virtual environment myvenv. Please report bugs you may encounter, this is the proper way to setup the environment without risks to break your system python, but likely not the most tested…

• If you are running the system python interpreter (not in a virtual environment), you should then install this package on your system (in /usr/local/lib/python2.7/site-packages, also via the same pip command). Although this is definitely not a recommended way to setup python packages, it is the defacto standard way for ROS.

To run the self tests, using entry_points defined in setup.py:

pyros_setup --pytest

OR using the python package directly:

python -m pyros_setup --pytest

OR using pytest specifically, optionally specifying the distro you want to use

py.test -s --pyargs pyros_setup --distro=indigo

OR via tox to test multiple env at once (with only one ROS distro)

tox -- --distro=indigo

It can also be used from source inside a catkin workspace in the same way. The workspace act as a virtual environment (using https://github.com/asmodehn/catkin_pip). This is useful for development along with ROS packages:

$ catkin_make
$ source devel/setup.bash
$ python -m pyros_setup
$ pyros_setup
$ py.test -s --pyargs pyros_setup --distro=indigo

HowTo code

Basically it allows you to do this:

try:
    import rospy
    import roslaunch
    import rosgraph
    import rosnode
except ImportError:  # if ROS environment is not setup, we emulate it.
    import pyros_setup
    pyros_setup.configurable_import().configure('mysetup.cfg').activate()  # this will use mysetup.cfg from pyros-setup instance folder
    import rospy
    import roslaunch
    import rosgraph
    import rosnode

With mysetup.cfg in pyros-setup instance folder containing:

import os
WORKSPACES=[os.path.join('home', 'user', 'ROS', 'workspace', 'devel')]
DISTRO='indigo'

Note: If you know any easier / less tricky / more pythonic way of handling configurable dynamic imports, let me know!

HowTo deploy

If you want to use pyros-setup, you should use the pip package, since the whole point is to provide access to ROS from pure python environment. This is now possible thanks to [catkin_pip](https://github.com/asmodehn/catkin_pip)

Remarks

Although it would technically be possible to build a ROS package from this source, this will NOT be done. The catkin build system is only here to help having pyros-setup in a source workspace while developing on it. When using ROS directly this package is not needed, and having it installed among ROS packages would cause much useless confusion with python import mechanism.

Troubleshooting

1. Wrong ROS Distro

If you run self tests like this

$ pyros_setup --pytest

You might get

========================================================================================================= test session starts =========================================================================================================
platform linux2 -- Python 2.7.6, pytest-3.0.1, py-1.4.31, pluggy-0.3.1
rootdir: /home/alexv/Projects/pyros-setup, inifile:
collected 1 items

pyros_setup/tests/test_setup.py WARNING:root:Error detected while importing ROS python modules. Attempting fix via ROS setup emulation...
WARNING:root: => Pyros_setup v0.1.99 Emulating ROS setup now for distro kinetic and workspaces ()
WARNING:root:Configured workspace /opt/ros/kinetic not found. Please double check your configuration. Skipping...
WARNING:root: => ROS setup emulation done.
[...]
E       ImportError: No module named rospy

/usr/lib/python2.7/importlib/__init__.py:37: ImportError
====================================================================================================== 1 failed in 0.02 seconds =======================================================================================================

This is what happens when the configuration (default) tries to use a ROS distro you do NOT have on your system rospy just cannot be found.

To try detecting multiple ROS distro on your system you can pass the –distro option.

2. VirtualEnv not using system packages

If, upon running test with

$ pyros_setup --pytest --distro=indigo

You get

========================================================================================================= test session starts =========================================================================================================
platform linux2 -- Python 2.7.6, pytest-3.0.1, py-1.4.31, pluggy-0.3.1
rootdir: /home/alexv/Projects/pyros-setup, inifile:
collected 1 items

pyros_setup/tests/test_setup.py WARNING:root:Error detected while importing ROS python modules. Attempting fix via ROS setup emulation...
WARNING:root: => Pyros_setup v0.1.99 Emulating ROS setup now for distro indigo and workspaces ()
WARNING:root:Prepending path /opt/ros/indigo to CMAKE_PREFIX_PATH
WARNING:root:Prepending path /opt/ros/indigo/bin to PATH
WARNING:root:Prepending path /opt/ros/indigo/lib to LD_LIBRARY_PATH
WARNING:root:Prepending path /opt/ros/indigo/lib/pkgconfig to PKG_CONFIG_PATH
WARNING:root:Prepending path /opt/ros/indigo/lib/python2.7/dist-packages to PYTHONPATH
WARNING:root: => ROS setup emulation done.
ERROR:root:importlib.import_module(rospy) FAILED : No module named yaml
ERROR:root:Make sure you have installed the yaml python package
[...]
E   ImportError: No module named yaml

/opt/ros/indigo/lib/python2.7/dist-packages/rospy/client.py:47: ImportError
====================================================================================================== 1 failed in 0.03 seconds =======================================================================================================

This means your virtualenv cannot access system (and ROS) packages.

This is easily fixed by removing <virtualenv_dir>/lib/pythonX.Y/no-global-site-packages.txt to allow your virtualenv to also include system (and ROS) packages.