上下文管理

import  contextlib
@contextlib.contextmanager
def work_state(state_list,worker_thread):
    state_list.append(worker_thread)
    try:
        yield
    finally:
        state_list.remove(worker_thread)
free_list=[]
current_thread="alex"
with work_state(free_list,current_thread):
    print(123)
    print(456)

#以下为执行结果：
123
456

import  contextlib
import  socket

@contextlib.contextmanager
def context_socket(host,port):
    sk=socket.socket()
    sk.bind((host,port))
    sk.listen(5)
    try:
        yield sk
    finally:
        sk.close()
with context_socket(‘127.0.0.1‘,8888) as sock:
    print(sock)

#以下为执行结果:
<socket.socket fd=224, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=(‘127.0.0.1‘, 8888)>