關於以下python腳本為何未實現Lock機制的任何建議？
[英]Any suggestions on why the Lock mechanism isn't getting implemented in the below python script?
問題描述
我正在使用多線程匿名登錄到公共FTP站點，並列出主機名以及相應的目錄。 我正在使用threading.lock（）方法執行相同操作，但是它似乎無法正常工作，並且會隨機打印主機和相應目錄。 我要去哪里錯了？ 下面是我正在運行的代碼。
#!/usr/bin/python
import threading
import Queue
from ftplib import FTP
ftpSiteList = [ 'ftp.x.org', 'ftp4.FreeBSD.org', 'ftp.ncsa.uiuc.edu', 'ftp.crans.org' ]
threadsList = []
class workerClass(threading.Thread):
def __init__(self,queue,tid):
threading.Thread.__init__(self)
self.queue = queue
self.lock = threading.Lock()
self.tid = tid
print "Worker Thread %d reporting for Service !!!"%self.tid
def run(self):
self.lock.acquire()
try:
while True:
host = ''
try:
host = self.queue.get(timeout=1)
except Queue.Empty:
print "Worker thread %d exiting. "%(self.tid)
return
try:
conn = FTP(host)
conn.login()
print 'Host: ' +host
print conn.retrlines('LIST')
except:
print "Error in listing HOST "+host
raise
self.queue.task_done()
finally:
self.lock.release()
queue = Queue.Queue()
for threads in range(5):
worker = workerClass(queue,threads)
worker.setDaemon(True)
worker.start()
threadsList.append(worker)
print "Thread %d started .."%threads
for host in ftpSiteList:
queue.put(host)
queue.join()
for threads in threadsList:
threads.join()
print "Scanning completed !!!"
================================================== =========================
輸出低於
Worker Thread 0 reporting for Service !!!
Thread 0 started ..
Worker Thread 1 reporting for Service !!!
Thread 1 started ..
Worker Thread 2 reporting for Service !!!
Thread 2 started ..
Worker Thread 3 reporting for Service !!!
Thread 3 started ..
Worker Thread 4 reporting for Service !!!
Thread 4 started ..
Worker thread 4 exiting.
Host: ftp4.FreeBSD.org
Host: ftp.crans.org
Host: ftp.ncsa.uiuc.edu
-rw-r--r-- 1 ftp ftp 5430 Jul 19 2014 favicon.ico
-rw-r--r-- 1 ftp ftp 655 Nov 24 2014 index.html
drwxr-xr-x 3 ftp ftp 3 Jul 19 2014 pub
226 Directory send OK.
lrwxrwxrwx 1 0 0 10 Jun 14 2012 custom -> pub/custom
lrwxrwxrwx 1 9865 9865 10 May 24 2012 debian -> pub/debian
lrwxrwxrwx 1 9865 9865 20 May 27 2012 debian-backports -> pub/debian-backports
lrwxrwxrwx 1 9865 9865 22 May 24 2012 debian-multimedia -> pub/debian-multimedia/
lrwxrwxrwx 1 9865 9865 20 May 24 2012 debian-security -> pub/debian-security/
lrwxrwxrwx 1 0 0 10 Apr 14 2014 events -> pub/events
drwxrwsr-x 27 0 4 4096 Jan 27 2014 git
drwx------ 2 9865 9865 16384 Jun 08 2012 lost+found
drwxr-xr-x 14 9865 9865 4096 Nov 26 2013 pub
lrwxrwxrwx 1 9865 9865 11 May 24 2012 ubuntu -> pub/ubuntu/
lrwxrwxrwx 1 0 0 12 Jun 14 2012 videolan -> pub/videolan
226 Directory send OK.
Worker thread 1 exiting.
-rw-r--r-- 1 12873 floppy 784 Aug 22 1994 .index
-rw-r--r-- 1 80 root 663 Jan 7 1995 .message
-rw-r--r-- 1 80 root 25819 Dec 29 1994 Brochure
drwx------ 2 80 ncsa 2048 Jun 16 1998 Cyberia
drwxr-xr-x 2 12873 root 2048 Aug 22 1994 DTM
drwxrwxrwx 4 root root 2048 Dec 4 2003 Director
drwxr-xr-x 13 14453 root 2048 Aug 22 1994 Documentation
drwxr-xr-x 9 root root 2048 Feb 5 1997 Education
drwxrwxrwx 2 root root 2048 Apr 9 1996 FigLeaf
drwxr-xr-x 13 19099 root 2048 Aug 22 1994 GlobalModels
drwxr-xr-x 8 12873 root 2048 May 17 1996 Mac
drwxr-xr-x 10 12873 root 2048 Feb 15 2002 Mosaic
drwxr-xr-x 5 12873 root 2048 Jan 5 1995 PC
-rw-r--r-- 1 80 root 16557 Jan 3 1995 README
-rw-r--r-- 1 12873 root 1933 Jan 12 1995 README.FIRST
drwxr-xr-x 5 12873 root 2048 Feb 15 2002 SGI
drwxr-xr-x 4 12873 root 2048 Dec 20 1994 Telnet
drwxr-xr-x 7 12873 root 2048 Aug 24 1994 Unix
drwxrwxrwx 12 root root 2048 Jan 30 2004 VR
drwxr-xr-x 24 12873 root 2048 May 31 1997 Visualization
drwxrwxrwx 2 root root 2048 May 20 1996 Vosaic
drwxr-xr-x 6 12873 root 2048 May 16 1997 Web
drwxrwxrwx 24 root root 2048 Sep 22 2006 aces
drwxr-xr-x 10 12873 root 2048 Aug 22 1994 aff
drwxrwxrwx 2 root root 2048 Jul 24 2002 aips
drwxrwxrwx 12 root root 43008 Aug 27 00:30 alg
drwxrwxrwx 4 root root 2048 Mar 17 2003 benchmarks
dr-xrwxrwx 2 root root 2048 Apr 21 2006 bin
drw-r--r-- 2 15332 wheel 2048 Jan 27 1999 chemistry
drwxrwxrwx 68 root root 4096 Apr 12 2007 cosmic
drwx------ 3 80 ncsa 2048 May 24 2002 dbalsara
drwx------ 2 80 games 2048 Dec 23 1997 emerge
drwxr-xr-x 3 80 root 2048 Jun 27 2006 etc
drwxr-xr-x 4 80 sys 2048 May 12 2009 incoming
drwx------ 3 80 games 2048 Aug 25 1997 java
drwx------ 2 80 games 2048 Jul 22 1997 joule
drwx------ 7 80 ncsa 2048 Jun 5 2000 lca
drwxrwxrwx 2 root root 2048 Nov 9 2001 lib
drwxrwxrwx 16 root root 2048 Sep 25 2003 media
drwxr-xr-x 14 12873 root 2048 Nov 21 2001 misc
drwxrwxrwx 21 root root 2048 Mar 16 2001 ncsapubs
drwxrwxrwx 14 root root 2048 Oct 3 2007 netdev
drwxrwxr-x 31 12984 wheel 2048 Mar 19 2015 outgoing
drwxr-xr-x 4 12873 root 2048 Dec 21 1999 sc22wg5
drwx------ 2 nobody games 2048 Mar 15 2007 security
drwxr-xr-x 2 root root 2048 Dec 22 1999 x3j3
Worker thread 3 exiting.
226 Transfer complete.
Worker thread 2 exiting.
Host: ftp.x.org
-rw-r--r-- 2 ftp ftp 479 Nov 6 2001 banner2
lrwxrwxrwx 1 ftp ftp 7 Oct 9 2005 bin -> usr/bin
drwxr-xr-x 34 ftp ftp 4096 Nov 6 2001 contrib
d--x--x--x 2 ftp ftp 4096 Aug 8 2001 dev
drwxr-xr-x 2 ftp ftp 4096 Oct 12 1998 digest
d--x--x--x 3 ftp ftp 4096 Aug 8 2001 etc
-rw-r--r-- 1 ftp ftp 3075 Oct 7 1998 GettingBroadway
-rw-r--r-- 1 ftp ftp 3075 Oct 7 1998 GettingR6.3
-rw-r--r-- 1 ftp ftp 1847 Feb 1 1999 GettingR6.4
-rw-r--r-- 1 ftp ftp 1378 Aug 24 2000 GettingR6.5.1
-rw-r--r-- 1 ftp ftp 1229 Apr 24 2001 GettingR6.6
-rw-r--r-- 1 ftp ftp 301 Dec 22 2005 GettingR6.7
-rw-r--r-- 1 ftp ftp 396 Dec 22 2005 GettingR6.8
-rw-r--r-- 1 ftp ftp 396 Dec 22 2005 GettingR6.9
-rw-r--r-- 1 ftp ftp 396 Dec 22 2005 GettingR7.0
-rw-r--r-- 1 ftp ftp 195 Dec 30 2004 MIRROR.README
drwxrwxr-x 36 ftp ftp 4096 Jun 30 2013 pub
drwxr-xr-x 56 ftp ftp 24576 May 4 2001 R5contrib
drwxr-xr-x 2 ftp ftp 4096 May 4 2001 rcsfaq
-r--r--r-- 1 ftp ftp 1571 Dec 22 2005 README
lrwxrwxrwx 1 ftp ftp 6 Nov 27 2005 README.txt -> README
d--x--x--x 5 ftp ftp 4096 Aug 8 2001 usr
-rw-r--r-- 2 ftp ftp 479 Nov 6 2001 welcome.msg
226 Transfer complete
Worker thread 0 exiting.
Scanning complete !!!
2 個解決方案
解決方案1
1 已采納 2015-10-20 04:14:57
這是因為lock變量是一個實例變量，而不是您希望的線程之間共享的變量。
您在編寫時將變量定義為實例變量
def __init__(self, queue, tid):
...
self.lock = thread.Lock()
...
您可以通過以下方式檢查
def __init__(self,queue,tid):
threading.Thread.__init__(self)
self.queue = queue
self.tid = tid
print "%d !!!"% id(self.lock) # all threads print different ids
對於每個線程，這給出一個不同的id ，這意味着它們是獨立的對象。
您要創建一個類變量。 類變量在類的所有實例之間共享。
class workerClass(threading.Thread):
lock = threading.Lock()
def __init__(self,queue,tid):
threading.Thread.__init__(self)
self.queue = queue
self.tid = tid
def run(self):
lock.acquire()
# do stuff
lock.release()
解決方案2
0 2015-10-20 06:05:36
#!/usr/bin/python
import threading
import Queue
from ftplib import FTP
ftpSiteList = [ 'ftp.x.org', 'ftp4.FreeBSD.org', 'ftp.ncsa.uiuc.edu','ftp.crans.org' ]
threadsList = []
class workerClass(threading.Thread):
lock = threading.Lock()
def __init__(self,queue,tid):
threading.Thread.__init__(self)
self.queue = queue
self.tid = tid
print "Worker Thread %d reporting for Service with the lock id %d!!!"%(self.tid,id(workerClass.lock))
def run(self):
try:
workerClass.lock.acquire()
while True:
host = ''
try:
host = self.queue.get(timeout=1)
except Queue.Empty:
print "Worker thread %d exiting. "%(self.tid)
return
try:
conn = FTP(host)
conn.login()
print 'Host: ' +host
print conn.retrlines('LIST')
except:
print "Error in listing HOST "+host
raise
self.queue.task_done()
finally:
workerClass.lock.release()
queue = Queue.Queue()
for threads in range(5):
worker = workerClass(queue,threads)
worker.setDaemon(True)
worker.start()
threadsList.append(worker)
print "Thread %d started .."%threads
for host in ftpSiteList:
queue.put(host)
queue.join()
for threads in threadsList:
threads.join()
print "Scanning completed !!!"
為什么在Python的雙端隊列中沒有實現__add__？
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