Source code for rocon_python_comms.nodes

#
# License: BSD
#   https://raw.github.com/robotics-in-concert/rocon_tools/license/LICENSE
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# Description
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"""
.. module:: nodes
   :platform: Unix
   :synopsis: Useful methods relating to ros nodes.


This module contains anything relating to introspection or manipulation
of ros nodes.

----

"""

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# Imports
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import rosnode
from .exceptions import NotFoundException

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# Methods
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def find_node(wanted_node_name, unique=False):
    '''
      Do a lookup to find a node with the given name. The given name is treated as the unresolved node name.
      Hence this lookup will find nodes with the same name, but different namespaces.

      This will raise exceptions, if the node couldn't be found
      or in case unique is set multiple nodes with the same name are found.

      :param str wanted_node_name: unresolved name of the node looked for (e.g. 'gateway', not '/concert/gateway')

      :returns: the fully resolved name of the node (unique) or list of fully resolved names (non-unique)
      :rtype: str

      :raises: :exc:`.NotFoundException`

      :todo: accept resolved names -> https://github.com/robotics-in-concert/rocon_tools/issues/30
      :todo: timeout -> https://github.com/robotics-in-concert/rocon_tools/issues/15
    '''
    available_nodes = rosnode.get_node_names()
    found_nodes = []
    for resolved_node_name in available_nodes:
        node_name = resolved_node_name[(resolved_node_name.rfind('/') + 1):len(resolved_node_name)]
        if node_name == wanted_node_name:
            found_nodes.append(resolved_node_name)

    if len(found_nodes) == 0:
            raise NotFoundException("Node '" + str(wanted_node_name) + "' not found.")
    if unique:
        if len(found_nodes) > 1:
            raise NotFoundException('More then one node with the same name found:' + str(found_nodes))

    return found_nodes