python:对url api调用做简单负载均衡

import random

class UrlApiBalancer(object):
    def __init__(self):
        self.url = ''
        self.port_range=[0,0]

    def fill_url(self, *args):
        if not self.url:
            raise Exception('UrlApiBalancer url is empty')
        if not self.port_range[0] or not self.port_range[1]:
            raise Exception('UrlApiBalancer port_range is empty')

        url = self.url
        port = random.randint(self.port_range[0],
                                        self.port_range[1])
        url = url.replace('{port}', str(port))
        url = url.format(*args)
        return url

url_blc = UrlApiBalancer()
url_blc.url = 'http://www.superpig.win:{port}/{}/{}'
url_blc.port_range = [8000, 8100]

print(url_blc.fill_url('ha', 'ha'))