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假设我想从不同的位置 ping 一些东西，所以我将 ping 命令行工具包装到 python 中并使用 pyro4 prc 库来调用它。

我有一个 python Pyro4 名称服务器

import Pyro4
Pyro4.config.COMPRESSION = True
Pyro4.naming.startNSloop("ipofnameserver")

和简单的 ping 服务器：

class Pinger(object):
    def ping(self, host):
        return subprocess.check_output(["ping", host, "-c 4"])

pinger = Pinger()

daemon = Pyro4.Daemon()                 # make a Pyro daemon
ns  = Pyro4.locateNS(host = "ipofnameservre", port=9090) # find the name server
uri = daemon.register(pinger)   # register the greeting object as a Pyro object
print ns.register("location1", uri) 
print "Ready. Object uri =", uri      # print the uri so we can use it in the client later
daemon.requestLoop()

只要我只有两个 pingserver 一切都好，但是在我添加第三个名称服务器后停止响应。当然，每个 pingserver 都有唯一的名称。

例如，我想检查服务器的可用性：

ns  = Pyro4.locateNS(host = "nameserverip", port=9090)
names = ns.list().keys()
print names
print ns.list()
for n in names:
    if n == 'Pyro.NameServer': continue
    proxy = Pyro4.Proxy("PYRONAME:"+n)
    try:
        print n, proxy._Proxy__pyroCreateConnection()
    except:
        print "offline"

这适用于两个 pingserver，但三个它只是等待一些东西。此脚本的回溯以 ctrl+C 终止：

   ns  = Pyro4.locateNS(host = "nameserverip", port=9090)
  File "/usr/local/lib/python2.7/dist-packages/Pyro4/naming.py", line 319, in locateNS
    proxy.ping()
  File "/usr/local/lib/python2.7/dist-packages/Pyro4/core.py", line 146, in __call__
    return self.__send(self.__name, args, kwargs)
  File "/usr/local/lib/python2.7/dist-packages/Pyro4/core.py", line 250, in _pyroInvoke
    self.__pyroCreateConnection()
  File "/usr/local/lib/python2.7/dist-packages/Pyro4/core.py", line 312, in __pyroCreateConnection
    msgType, flags, seq, data = MessageFactory.getMessage(conn, None)
  File "/usr/local/lib/python2.7/dist-packages/Pyro4/core.py", line 665, in getMessage
    headerdata = connection.recv(cls.HEADERSIZE)
  File "/usr/local/lib/python2.7/dist-packages/Pyro4/socketutil.py", line 323, in recv
    return receiveData(self.sock, size)
  File "/usr/local/lib/python2.7/dist-packages/Pyro4/socketutil.py", line 104, in receiveData
    data=sock.recv(size, socket.MSG_WAITALL)

strace 显示以下内容：

socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3 fcntl(3, F_GETFL)
= 0x2 (标志 O_RDWR) fcntl(3, F_SETFL, O_RDWR) = 0 connect(3, {sa_family=AF_INET, sin_port=htons(9090), sin_addr= inet_addr("ipofnameserver")}, 16) = 0 setsockopt(3, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0 recvfrom(3,

以下示例也无法正常工作，因为它无法将名称解析为 pyro_uri，因为它只是在等待上一个示例中的内容。这个例子的有趣之处在于它打印了 fls，其中包含所有远程 pingserver 的名称。然后添加第四个 pingserver 我什至无法打印已注册 pingserver 的名称。

def _ping((host, firing_location)):
    pinger = Pyro4.Proxy("PYRONAME:" + firing_location)
    return pinger.ping(host)

def ping(host):
    ns  = Pyro4.locateNS(host = "178.209.52.240", port=9090)
    names = ns.list().keys()
    fls = []
    for name in names:
        if name == 'Pyro.NameServer': continue
        fls.append(name)
    print fls
    p = Pool(len(fls))
    jobs = p.map(_ping, zip([host]*len(fls), fls) )
    for j in jobs:
        print j.split("/")[-3], "±", j.split("/")[-1][:-1]
    return jobs

我为此苦苦挣扎了两天，不知道我的代码有什么问题。

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