Fix #658, implemented a Python class that works as a context manager for sockets (#659)

# Author:

#    Giuseppe Carboni, <giuseppe.carboni@inaf.it>

import socket

import time

from contextlib import contextmanager

import ComponentErrorsImpl

class Connection(object):

    """This class implements a contextmanager for a socket.

    Usage example:

    with Connection(('127.0.0.1', 10000)) as s:

        s.sendall('COMMAND\n')

        answer = s.recv(1024)

    :param: address, a tuple containing IP address and PORT for the socket

    :param: timeout, connection timeout, in seconds

    """

    def __init__(self, address, timeout=2):

        self.address = address

    def __enter__(self):

        self.s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

        connected = 1

        t0 = time.time()

        while time.time() - t0 < timeout:

            connected = self.s.connect_ex(self.address)

            if connected == 0:

                break

            time.sleep(0.01)

        if connected:

            reason = 'Could not reach the device!'

            from IRAPy import logger

            logger.logError(reason)

            exc = ComponentErrorsImpl.SocketErrorExImpl()

            exc.setData('Reason', reason)

            raise exc

        return self.s

    def __exit__(self, type, value, traceback):

        self.s.close()

list of modules:

  - customlogging: custom logging functionalities to replace standard logging

  - bsqueue: BoundedSortedQueue class implements a priority queue structure

  - Connection: Connection class implements a contextmanager for a socket

"""

import customlogging

import ACSLog

import Connection

#Some comments required here. The custom logger mechanism is not working in python. 

#do the way to separate the system logs to the ones do be shown to the user is to use different