Source code for tuna.console.backend

"""
This module's scope covers background processes.
"""

import logging
import sys
import threading
import tuna
from tuna.zeromq.zmq_proxy import zmq_proxy

class backend ( object ):
    """
    This class' responsability is to wrap calls for all necessary background processes for Tuna.
    """
    def __init__ ( self ):
        super ( backend, self ).__init__ ( )
        self.__version__ = "0.2.0"
        self.changelog = {
            "0.2.0" : "Tuna 0.14.0 : improved docstrings.",
            "0.1.0" : "Initial changelog version."
            }
        self.log = logging.getLogger ( __name__ )
        self.log.setLevel ( logging.INFO )

        self.lock = False

    def start ( self ):
        """
        This method will launch the ZeroMQ proxy instance and the database on the first time it is called. Subsequent calls are ignored.        

        Example::

            b = tuna.console.backend ( )
            b.start ( )
        """
        self.log.debug ( "%s %s" % ( sys._getframe ( ).f_code.co_name,
                                     sys._getframe ( ).f_code.co_varnames ) )

        if self.lock == False:
            self.lock = True

            self.zmq_proxy_instance = zmq_daemon ( )
            self.zmq_proxy_instance.start ( )

            self.db = tuna.io.database ( )
            self.db.start ( )

class zmq_daemon ( threading.Thread ):
    """
    This class encapsulates a ZeroMQ proxy running as an independent thread.

    It inherits from the :ref:`threading_label`.Thread class, and it auto-starts its thread execution. Clients are expected to use its .join ( ) method before using its results.

    This class is not intended for public use, and therefore its signature is not exposed by default.

    Example::

        from tuna.console.backend import *
        tz = tuna.console.backend.zmq_daemon ( )
        tz.start ( )
    """
    def __init__ ( self ):
        super ( zmq_daemon, self ).__init__ ( )
        self.__version__ = "0.1.0"
        self.changelog = {
            "0.1.0" : "Initial changelog version."
            }
        self.log = logging.getLogger ( __name__ )
        self.zmq_proxy_instance = zmq_proxy ( )

        self.daemon = True

    def run ( self ):
        """
        This method is called when the thread object's start ( ) method is called. 
        It will call this object's ZeroMQ proxy instance's run ( ) method.

        Example::

            from tuna.console.backend import *
            tz = tuna.console.backend.zmq_daemon ( )
            tz.start ( )
        """
        self.zmq_proxy_instance.run ( )