Source code for perfsim.service_chain.load_balancer

#  Copyright (C) 2020 Michel Gokan Khan
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License along
#  with this program; if not, write to the Free Software Foundation, Inc.,
#  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
#  This file is a part of the PerfSim project, which is now open source and available under the GPLv2.
#  Written by Michel Gokan Khan, February 2020

#

from typing import List




class LoadBalancer:
    """
    This class is responsible for load balancing. It can be used to balance the load between multiple items.
    """
    def __init__(self,
                 items: List = [],
                 algorithm: str = "round_robin"):
        self.items = items
        self.algorithm = algorithm
        self.__current_item = 0



    def next(self):
        """
        Get the next item based on the load balancing algorithm.

        :return:  The next item.
        """
        if self.algorithm == "round_robin":
            current = self.__current_item

            if self.__current_item + 1 < len(self.items):
                self.__current_item += 1
            else:
                self.__current_item = 0

            return self.items[current]
        else:
            raise Exception("Only round-robin based load balancing is available at this moment.")