python脚本在一段时间后停止

Question

我在 Amazon EC2 服务器上有一个 python 脚本，它从两个不同的服务器（使用 urllib 和 http.request）请求数据，然后将该数据记录在一个文本文件中。它必须运行很长时间。我正在使用 nohup 让它在后台运行。

问题是，它会在一段时间后停止（有时会持续 24 小时，有时会持续 2 小时，情况会有所不同）。我没有收到错误消息或任何东西。它只是停止并且收到的最后一串字符只是作为不完整的字符串保存在文本文件中（只是可以从远程服务器读取的信息）。

什么可能导致这个问题？

这是我的代码：

import urllib3 #  sudo pip install urllib3 --upgrade
import time

urllib3.disable_warnings() # Disable urllib3 warnings about unverified connections
http = urllib3.PoolManager()

f = open('okcoin.txt', 'w')
f2 = open('bitvc.txt', 'w')

while True:
    try:
        r = http.request("GET","https://www.okcoin.com/api/v1/future_ticker.do?symbol=btc_usd&contract_type=this_week")
        r2 = http.request("GET","http://market.bitvc.com/futures/ticker_btc_week.js ")
    except: # catch all exceptions
        continue

    #Status codes of 200 if it got an OK from the server
    if r.status != 200 or r2.status != 200 or r.data.count(',') < 5 or r2.data.count(',') < 5: # avoids blank data, there should be at least 5 commas so that it's correct data
        continue; # Try to read again if there was a problem with one reading

    received = str(time.time()) # Timestamp of when the information was received to the server running this python code

    data = r.data + "," + received + "\r\n"
    data2 = r2.data + "," + received + "\r\n"        

    print data,r.status
    print data2, r.status

    f.write(data)
    f2.write(data2)

    time.sleep(0.5)
    f.flush() #flush files
    f2.flush()
f.close()
f2.close()

编辑：我通过 ssh 使用屏幕打开了程序。它又停了下来。如果我按“CTRL+C”停止它，这就是我得到的：

^CTraceback (most recent call last):
  File "tickersave.py", line 72, in <module>
    r2 = http.request("GET","http://market.bitvc.com/futures/ticker_btc_week.js")
  File "/usr/local/lib/python2.7/dist-packages/urllib3/request.py", line 68, in request
    **urlopen_kw)
  File "/usr/local/lib/python2.7/dist-packages/urllib3/request.py", line 81, in request_encode_url
    return self.urlopen(method, url, **urlopen_kw)
  File "/usr/local/lib/python2.7/dist-packages/urllib3/poolmanager.py", line 153, in urlopen
    response = conn.urlopen(method, u.request_uri, **kw)
  File "/usr/local/lib/python2.7/dist-packages/urllib3/connectionpool.py", line 541, in urlopen
    **response_kw)
  File "/usr/local/lib/python2.7/dist-packages/urllib3/response.py", line 284, in from_httplib
    **response_kw)
  File "/usr/local/lib/python2.7/dist-packages/urllib3/response.py", line 104, in __init__
    self._body = self.read(decode_content=decode_content)
  File "/usr/local/lib/python2.7/dist-packages/urllib3/response.py", line 182, in read
    data = self._fp.read()
  File "/usr/lib/python2.7/httplib.py", line 551, in read
    s = self._safe_read(self.length)
  File "/usr/lib/python2.7/httplib.py", line 658, in _safe_read
    chunk = self.fp.read(min(amt, MAXAMOUNT))
  File "/usr/lib/python2.7/socket.py", line 380, in read
    data = self._sock.recv(left)

有什么线索吗？我应该添加超时还是什么？

Answer 1

收集你程序的所有输出，你会发现一个很好的提示关于哪里出了问题。也就是说，一定要收集stdout和stderr。为此，您可能希望这样调用您的程序：

$ nohup python script.py > log.outerr 2>&1 &

这会在 log.outerr 文件中收集 stdout 和 stderr，并在后台和 tty 中启动您的程序。在你的程序停止工作后调查log.outerr 可能会很有启发性，我猜。