IOError：[Errno套接字错误] [Errno 8]提供的节点名或服务名，或者未知

Question

I was trying to scrape and save the stock data to SQL using multithreading from Yahoo finance. However, I got the following error:

*Exception in thread Thread-3091:
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 763, in run
    self.__target(*self.__args, **self.__kwargs)
  File "todatabase.py", line 19, in th
    htmltext = urllib.urlopen(base).read()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib.py", line 87, in urlopen
    return opener.open(url)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib.py", line 213, in open
    return getattr(self, name)(url)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib.py", line 350, in open_http
    h.endheaders(data)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/httplib.py", line 1049, in endheaders
    self._send_output(message_body)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/httplib.py", line 893, in _send_output
    self.send(msg)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/httplib.py", line 855, in send
    self.connect()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/httplib.py", line 832, in connect
    self.timeout, self.source_address)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/socket.py", line 557, in create_connection
    for res in getaddrinfo(host, port, 0, SOCK_STREAM):
IOError: [Errno socket error] [Errno 8] nodename nor servname provided, or not known* 

Here is my code:

from threading import Thread
import sqlite3
import urllib
import re

conn = sqlite3.connect('stock.sqlite')
cur = conn.cursor()

cur.execute('''CREATE TABLE IF NOT EXISTS Stock
    (symbol TEXT UNIQUE PRIMARY KEY, price NUMERIC) ''')

dic = {}

def th(ur):
    base = "http://finance.yahoo.com/q?s=" + ur
    regex = '<span id="yfs_l84_[^.]*">(.+?)</span>'
    pattern = re.compile(regex)
    htmltext = urllib.urlopen(base).read()
    results = re.findall(pattern, htmltext)

    try:
        dic[ur] = results[0]
    except:
        print 'got a error!'

symbolslist = open("symbols.txt").read()
symbolslist = symbolslist.split("\n")
threadlist = []

for u in symbolslist:
    t = Thread(target = th, args = (u,))
    t.start()
    threadlist.append(t)

for b in threadlist:
    b.join()

for key, value in dic.items():
    print key, value

    cur.execute('INSERT INTO Stock(symbol,price) VALUES (?,?)',(key,value))
    conn.commit()

cur.close()

I think the mistake maybe in the multithreading part since I can get the data without using multithreading but at low speed.

With multithreading and this error, I only get 200+ (symbol,price) at the end rather than 3145.

I tried to change DNS and IP, doesn't solve it.

Answer 1

I remember that I had problems with multithreading and massive socket opening once. An additional lock solved the problem for me. I did not try to find the actuel problem, however. The urllib doc does not say anything about thread safety. You could try something like this:

global_lock = threading.Lock()
...
def th(ur):
    ...
    with global_lock:
        fd = urllib.urlopen(base)
    with fd:
        htmltext = fd.read()

EDIT

You could alternatively use single-threaded ( async IO ) code using a library like (eg) tornado or asyncio.

BTW, by using a sqlite connection per thread, you could store the scraped data right after retrieving it in the respective thread.

Answer 2

I got this error as well. I just add some sleep time for each thread and the problem is resolved. I used time.sleep(0.1).