Source code for araldo.endpoints

""" Communication endpoints
"""

import logging
from abc import ABCMeta, abstractmethod
import gevent


class PluginException(Exception):
    """ An end-point related exception
    """
    def __init__(self, msg):
        Exception.__init__(self, msg)


class EndPointBase(gevent.Greenlet):  # pylint: disable-msg=R0904
    """ Abstract base class for Araldo endpoints

        Concrete classes must implement Greenlet's _run method to
        process incoming messages and to enque them into gevent_queue
    """
    __meta__ = ABCMeta

    def __init__(self, **kwargs):
        self._name = kwargs["name"]
        self._logger = logging.getLogger("araldo")
        self._plugin_manager = kwargs["plugin_manager"]
        self._config = kwargs["config"]
        #import pdb; pdb.set_trace()
        marshalling_name = self._config.get("marshalling", "marshal-json")
        self._marshalling = self._get_marshalling(marshalling_name)
        self._gevent_queue = kwargs["gevent_queue"]
        gevent.Greenlet.__init__(self)

    def _get_marshalling(self, marshalling_name):
        """ Retrieve plugin instances for marshaller
        :return: marshalling-Object
        :rtype: araldo.marshalling.Marshaller
        """
        self._logger.debug("Obtaining marshaller '%s'" % marshalling_name)
        plugin_instances = self._plugin_manager.plugin_instances()
        marshalling_instances = plugin_instances["araldo.marshalling"]
        #self._logger.debug("### %s" % marshalling_instances)
        return marshalling_instances[marshalling_name]

    @abstractmethod
    def name(self):
        """ Short, human-readable name of plugin
        """
        return self._name

    @abstractmethod
    def marshalling(self):
        """ Short, human-readable name marshalling used
        """
        return self._marshalling

    @abstractmethod
    def plugin_manager(self):
        """ plugin manager for loading other plugins
        """
        return self._plugin_manager

    @abstractmethod
    def config(self):
        """ Plugin configuration sub-object
        """
        return self._config

    @property
    def gevent_queue(self):
        """ gevent target queue
        """
        return self._gevent_queue

    def description(self):
        """ Textual description of plugin
        """
        return "endpoint '%s'" % self.name()

    def __repr__(self):
        return ("EndPoint(name=%s,id=%s)"
                % (self.name(), id(self)))

    @abstractmethod
    def send(self, message):
        """ Send message to backend
        """