多线程 Python 应用程序和套接字连接的问题 [英] Problem with multi threaded Python app and socket connections
问题描述
我正在调查在具有 4G RAM 的 Ubuntu 机器上运行的 Python 应用程序的问题.该工具将用于审核服务器(我们更喜欢推出自己的工具).它使用线程连接到许多服务器，许多 TCP 连接失败.但是，如果我在启动每个线程之间添加 1 秒的延迟，那么大多数连接都会成功.我使用这个简单的脚本来调查可能发生的情况:
I'm investigating a problem with a Python app running on an Ubuntu machine with 4G of RAM. The tool will be used to audit servers (we prefer to roll our own tools). It uses threads to connect to lots of servers and many of the TCP connections fail. However, if I add a delay of 1 second between kicking off each thread then most connections succeed. I have used this simple script to investigate what may be happening:
#!/usr/bin/python
import sys
import socket
import threading
import time
class Scanner(threading.Thread):
def __init__(self, host, port):
threading.Thread.__init__(self)
self.host = host
self.port = port
self.status = ""
def run(self):
self.sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sk.settimeout(20)
try:
self.sk.connect((self.host, self.port))
except Exception, err:
self.status = str(err)
else:
self.status = "connected"
finally:
self.sk.close()
def get_hostnames_list(filename):
return open(filename).read().splitlines()
if (__name__ == "__main__"):
hostnames_file = sys.argv[1]
hosts_list = get_hostnames_list(hostnames_file)
threads = []
for host in hosts_list:
#time.sleep(1)
thread = Scanner(host, 443)
threads.append(thread)
thread.start()
for thread in threads:
thread.join()
print "Host: ", thread.host, " : ", thread.status
如果我在 time.sleep(1) 注释掉的情况下运行它，例如，300 台主机，许多连接失败并出现超时错误，而如果我延迟一秒钟，它们不会超时.我是否尝试过在更强大的机器上运行的另一个 Linux 发行版上的应用程序并且没有那么多连接错误?是因为内核限制吗?我可以做些什么来使连接正常工作而不会造成延迟?
If I run this with the time.sleep(1) commented out against, say, 300 hosts many of the connections fail with a timeout error, whereas they don't timeout if I put the delay of one second in. I did try the app on another Linux distro running on a more powerful machine and there weren't as many connect errors? Is it due to a kernel limitation? Is there anything I can do to get the connection to work without putting in the delay?
更新
我还尝试了一个程序，该程序限制了池中可用线程的数量.通过将其减少到 20，我可以让所有连接正常工作，但它每秒只检查大约 1 个主机.因此，无论我尝试什么(进入 sleep(1) 或限制并发线程数)，我似乎都无法每秒检查 1 个以上的主机.
I have also tried a program that limited the number of threads available in a pool. By reducing this down to 20 I can get all connects to work, but it only checks about 1 host a second. So whatever I try (putting in a sleep(1) or limiting the number of concurrent threads) I don't seem to able to check more than 1 host every second.
更新
我刚刚发现了这个问题 这似乎与我所看到的相似.
I just found this question which seems similar to what I am seeing.
更新
我想知道使用 Twisted 写这个是否有帮助?任何人都可以展示我的示例使用扭曲编写的样子吗?
I wonder if writing this using twisted might help? Could anyone show what my example would look like written using twisted?
推荐答案
你可以试试 gevent:
You could try gevent:
from gevent.pool import Pool
from gevent import monkey; monkey.patch_all() # patches stdlib
import sys
import logging
from httplib import HTTPSConnection
from timeit import default_timer as timer
info = logging.getLogger().info
def connect(hostname):
info("connecting %s", hostname)
h = HTTPSConnection(hostname, timeout=2)
try: h.connect()
except IOError, e:
info("error %s reason: %s", hostname, e)
else:
info("done %s", hostname)
finally:
h.close()
def main():
logging.basicConfig(level=logging.INFO, format="%(asctime)s %(message)s")
info("getting hostname list")
hosts_file = sys.argv[1] if len(sys.argv) > 1 else "hosts.txt"
hosts_list = open(hosts_file).read().splitlines()
info("spawning jobs")
pool = Pool(20) # limit number of concurrent connections
start = timer()
for _ in pool.imap(connect, hosts_list):
pass
info("%d hosts took us %.2g seconds", len(hosts_list), timer() - start)
if __name__=="__main__":
main()
每秒可以处理多个主机.
It can process more than one host per second.
2011-01-31 11:08:29,052 getting hostname list
2011-01-31 11:08:29,052 spawning jobs
2011-01-31 11:08:29,053 connecting www.yahoo.com
2011-01-31 11:08:29,053 connecting www.abc.com
2011-01-31 11:08:29,053 connecting www.google.com
2011-01-31 11:08:29,053 connecting stackoverflow.com
2011-01-31 11:08:29,053 connecting facebook.com
2011-01-31 11:08:29,054 connecting youtube.com
2011-01-31 11:08:29,054 connecting live.com
2011-01-31 11:08:29,054 connecting baidu.com
2011-01-31 11:08:29,054 connecting wikipedia.org
2011-01-31 11:08:29,054 connecting blogspot.com
2011-01-31 11:08:29,054 connecting qq.com
2011-01-31 11:08:29,055 connecting twitter.com
2011-01-31 11:08:29,055 connecting msn.com
2011-01-31 11:08:29,055 connecting yahoo.co.jp
2011-01-31 11:08:29,055 connecting taobao.com
2011-01-31 11:08:29,055 connecting google.co.in
2011-01-31 11:08:29,056 connecting sina.com.cn
2011-01-31 11:08:29,056 connecting amazon.com
2011-01-31 11:08:29,056 connecting google.de
2011-01-31 11:08:29,056 connecting google.com.hk
2011-01-31 11:08:29,188 done www.google.com
2011-01-31 11:08:29,189 done google.com.hk
2011-01-31 11:08:29,224 error wikipedia.org reason: [Errno 111] Connection refused
2011-01-31 11:08:29,225 done google.co.in
2011-01-31 11:08:29,227 error msn.com reason: [Errno 111] Connection refused
2011-01-31 11:08:29,228 error live.com reason: [Errno 111] Connection refused
2011-01-31 11:08:29,250 done google.de
2011-01-31 11:08:29,262 done blogspot.com
2011-01-31 11:08:29,271 error www.abc.com reason: [Errno 111] Connection refused
2011-01-31 11:08:29,465 done amazon.com
2011-01-31 11:08:29,467 error sina.com.cn reason: [Errno 111] Connection refused
2011-01-31 11:08:29,496 done www.yahoo.com
2011-01-31 11:08:29,521 done stackoverflow.com
2011-01-31 11:08:29,606 done youtube.com
2011-01-31 11:08:29,939 done twitter.com
2011-01-31 11:08:33,056 error qq.com reason: timed out
2011-01-31 11:08:33,057 error taobao.com reason: timed out
2011-01-31 11:08:33,057 error yahoo.co.jp reason: timed out
2011-01-31 11:08:34,466 done facebook.com
2011-01-31 11:08:35,056 error baidu.com reason: timed out
2011-01-31 11:08:35,057 20 hosts took us 6 seconds
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