python判断ip是否可达

python中使用subprocess来使用shell
关于threading的用法

from __future__  import print_function
import subprocess
import threading

def is_reachable(ip):
    if subprocess.call(["ping", "-c", "2", ip])==0:#只发送两个ECHO_REQUEST包
        print("{0} is alive.".format(ip))
    else:
        print("{0} is unalive".format(ip))
if __name__  == "__main__":
    ips = ["www.baidu.com","192.168.0.1"]
    threads = []
    for ip in ips:
        thr = threading.Thread(target=is_reachable, args=(ip,))#参数必须为tuple形式
        thr.start()#启动
        threads.append(thr)
    for thr in threads:
        thr.join()

改良 ：使用Queue来优化（FIFO）

from __future__  import print_function
import subprocess
import threading
from Queue import Queue
from Queue import Empty

def call_ping(ip):
    if subprocess.call(["ping", "-c", "2", ip])==0:
        print("{0} is reachable".format(ip))
    else:
        print("{0} is unreachable".format(ip))


def is_reachable(q):
    try:
        while True:
            ip = q.get_nowait()#当队列为空，不等待
            call_ping(ip)
    except Empty:
        pass


def main():
    q  = Queue()
    args = ["www.baidu.com", "www.sohu.com", "192.168.0.1"]
    for arg in args:
        q.put(arg)

    threads = []
    for i in range(10):
        thr = threading.Thread(target=is_reachable, args=(q,))
        thr.start()
        threads.append(thr)
    for thr in threads:
        thr.join()

if __name__ == "__main__":
    main()