pyros-rosinterface

ROS Interface sub-package for Pyros

This package provides an interface to the multiprocess ROS system, from python.

It is usable from a usual python virtual environment, following the normal python flow.

If required, it could also be used from ROS itself (to allow ROS packaging of pyros apps)

Assumptions

• OS is Ubuntu Xenial
• ROS is already known. If not, get informations and tutorials on http://ros.org

ROS Indigo System Setup

• Install useful python packages if you don’t already have them :

$ sudo apt-get install virtualenvwrapper

• Install ROS Kinetic : http://wiki.ros.org/kinetic/Installation/Ubuntu TL;DR :

$ sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'
$ sudo apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
$ sudo apt-get update
$ sudo apt-get install ros-kinetic-desktop
$ sudo rosdep init

ROS Talker Launch

Run the ROS talker and listener nodes as usual using roslaunch, in a separate terminal :

$ source /opt/ros/indigo/setup.bash 
$ roslaunch roscpp_tutorials talker_listener.launch 

Now you can run the pyros ROS interface node :

• from ROS itself (using the launcher provided),
• OR from a separate python virtual environment, that will access your ROS environment via pyros-setup.

Launching on ROS

TODO

TODO : using dynamic_reconfigure you can dynamically adjust what is exposed or not, without restarting the node.

Running from python

$ mkvirtualenv pyros-ros --system-site-packages
$ workon pyros-ros
(pyros-ros) $ pip install pyros_interfaces_ros
[...]
$ python -m pyros_interfaces_ros --sub ".*"
Re-adding /opt/ros/jade/lib/python2.7/dist-packages in front of sys.path
[pyros] Node started as [None <= ipc:///tmp/zmp-pyros-jRbGSV/services.pipe]
[INFO] [WallTime: 1493198579.422698] RosInterface pyros node started with args : []
[INFO] [WallTime: 1493198579.426763] [pyros_interfaces_ros.ros_interface] ROS Interface initialized with:
        -    services : []
        -    publishers : []
        -    subscribers : 
        - .*
        -    params : []
        -    enable_cache : False
        
[INFO] [WallTime: 1493198580.437716] /pyros Pyros.ros : Adding publisher interface /chatter <class 'std_msgs.msg._String.String'>
[INFO] [WallTime: 1493198580.843025] /pyros Pyros.ros : Adding publisher interface /rosout <class 'rosgraph_msgs.msg._Log.Log'>

TODO : tuning the configuration file will allow you to decide what to expose via the interface

From this point on, you should use the Pyros framework to be able to interract with the ROS system from another process. This will avoid any interference between ROS and your usual python environment.

Extras

TODO : using xonsh, you can dynamically access and modify ros internals, from a normal shell…