import threading
import json
import socket
import sys
from kazoo.client import KazooClient


# TCP服務端綁定端口開啟監聽，同時將自己注冊到zk
class ZKServer(object):
  def __init__(self, host, port):
    self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    self.host = host
    self.port = port
    self.sock.bind((host, port))
    self.zk = None

  def serve(self):
    """
    開始服務，每次獲取得到一個信息，都新建一個線程處理
    """
    self.sock.listen(128)
    self.register_zk()
    print("開始監聽")
    while True:
      conn, addr = self.sock.accept()
      print("建立鏈接%s" % str(addr))
      t = threading.Thread(target=self.handle, args=(conn, addr))
      t.start()

  # 具體的處理邏輯,只要接收到數據就立即投入工作，下次沒有數據本次鏈接結束
  def handle(self, conn, addr):
    while True:
      data=conn.recv(1024)
      if not data or data.decode('utf-8') == 'exit':
        break
      print(data.decode('utf-8'))
    conn.close()
    print('My work is done!!!')

  # 將自己注冊到zk，臨時節點，所以連接不能中斷
  def register_zk(self):
    """
    注冊到zookeeper
    """
    self.zk = KazooClient(hosts='127.0.0.1:2181')
    self.zk.start()
    self.zk.ensure_path('/rpc') # 創建根節點
    value = json.dumps({'host': self.host, 'port': self.port})
    # 創建服務子節點
    self.zk.create('/rpc/server', value.encode(), ephemeral=True, sequence=True)

if __name__ == '__main__':
  if len(sys.argv) < 3:
    print("usage:python server.py [host] [port]")
    exit(1)
  host = sys.argv[1]
  port = sys.argv[2]
  server = ZKServer(host, int(port))
  server.serve()

import random
import sys
import time
import json
import socket

from kazoo.client import KazooClient


# 客戶端連接zk,并從zk獲取可用的服務器列表
class ZKClient(object):
  def __init__(self):
    self._zk = KazooClient(hosts='127.0.0.1:2181')
    self._zk.start()
    self._get_servers()

  def _get_servers(self, event=None):
    """
    從zookeeper獲取服務器地址信息列表
    """
    servers = self._zk.get_children('/rpc', watch=self._get_servers)
    # print(servers)
    self._servers = []
    for server in servers:
      data = self._zk.get('/rpc/' + server)[0]
      if data:
        addr = json.loads(data.decode())
        self._servers.append(addr)

  def _get_server(self):
    """
    隨機選出一個可用的服務器
    """
    return random.choice(self._servers)

  def get_connection(self):
    """
    提供一個可用的tcp連接
    """
    sock = None
    while True:
      server = self._get_server()
      print('server:%s' % server)
      try:
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.connect((server['host'], server['port']))
      except ConnectionRefusedError:
        time.sleep(1)
        continue
      else:
        break
    return sock
if __name__ == '__main__':
  # 模擬多個客戶端批量生成任務，推送給服務器執行
  client = ZKClient()
  for i in range(40):
    sock = client.get_connection()
    sock.send(bytes(str(i), encoding='utf8'))
    sock.close()
    time.sleep(1)