[ros-users] catkin support in python rospkg

Brian Wightman brian.j.wightman at nasa.gov
Thu Jan 17 20:59:46 UTC 2013

In rosbuild I was able to use rospkg to grab all of the [cflags, lflags] 
exports out of a given package's manifest. Is there a plan to add this 
functionality for catkin packages?

My use-case may sound a bit odd:

I have been using scons rather than cmake to build packages. The rospkg 
manifest.xml parsing makes this rather painless (20 lines of python to 
collect all the build flags). Now with the "exports" buried in cmake 
files, I don't have a convenient way to access them.

In particular, I have code that forwards ROS messages between systems 
with separate roscore instances. I have to compile in a 
publisher/subscriber call for each message type so I've found it 
convenient to auto-generate the HPP/CPP files from a list of 
message-containing packages (std_msgs, sensor_msgs, etc.) using Python 
and rospkg.

If anyone's curious, here's the scons build code I've been using:

import os, rospkg
def load_ros_deps(env):
     pkg_name = os.path.basename(Dir('.').srcnode().abspath)
     depends = []
     for d in map(repr, rospkg.RosPack().get_manifest(pkg_name).depends):
         # load exports
         manifest = rospkg.RosPack().get_manifest(d)
         for f in [j for j in [manifest.get_export('cpp', i) for i in ['cflags', 'lflags']] if j]:
             allf = f[0].split('`')
             for conf in allf[1::2]:
             env.MergeFlags(env.ParseFlags(' '.join(allf[0::2])))
         pkg_path = os.path.dirname(manifest.filename)
         msg_path = os.path.join(pkg_path, 'msg_gen', 'cpp', 'include')
         if os.path.exists(msg_path):

env = Environment(
     ENV = {'PYTHONPATH': os.environ['PYTHONPATH'], # allow us to call rosboost-cfg
            'PKG_CONFIG_PATH': os.environ['PKG_CONFIG_PATH']},

Certainly I can achieve the same thing with CMake, but I find scons to 
be much nicer to work with.

Brian Wightman

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