ros_py_plugin_provider.py

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# Copyright (c) 2011, Dirk Thomas, TU Darmstadt
# All rights reserved.
#
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# modification, are permitted provided that the following conditions
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#     notice, this list of conditions and the following disclaimer.
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#     contributors may be used to endorse or promote products derived
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import os
import roslib
roslib.load_manifest('rqt_gui_py')
import rospy

from qt_gui.composite_plugin_provider import CompositePluginProvider

from python_qt_binding.QtCore import qDebug, qWarning

try:
    from rqt_gui.rospkg_plugin_provider import RospkgPluginProvider
    ActualRosPluginProvider = RospkgPluginProvider
except ImportError:
    from rqt_gui.roslib_plugin_provider import RoslibPluginProvider
    ActualRosPluginProvider = RoslibPluginProvider


class RosPyPluginProvider(CompositePluginProvider):

    def __init__(self):
        super(RosPyPluginProvider, self).__init__([ActualRosPluginProvider('rqt_gui', 'rqt_gui_py::Plugin')])
        self.setObjectName('RosPyPluginProvider')
        self._node_initialized = False

    def discover(self):
        descriptors = super(RosPyPluginProvider, self).discover()

        if not self._master_found():
            qWarning('RosPyPluginProvider.discover() could not find ROS master, all rospy-based plugins are disabled')
            # mark all plugins as "not_available"
            for descriptor in descriptors:
                descriptor.attributes()['not_available'] = 'no ROS master found (roscore needs to be started before the GUI)'

        return descriptors

    def load(self, plugin_id, plugin_context):
        self._init_node()
        return super(RosPyPluginProvider, self).load(plugin_id, plugin_context)

    def _master_found(self):
        try:
            rospy.get_master().getSystemState()
            return True
        except Exception:
            return False

    def _init_node(self):
        # initialize node once
        if not self._node_initialized:
            name = 'rqt_gui_py_node_%d' % os.getpid()
            qDebug('RosPyPluginProvider._init_node() initialize ROS node "%s"' % name)
            rospy.init_node(name, disable_signals=True)
            self._node_initialized = True