Odd/Weird errors with FTPLib

Bakes bakes at ymail.com
Mon Sep 14 22:18:01 CEST 2009


On Sep 13, 11:47 pm, MRAB <pyt... at mrabarnett.plus.com> wrote:
> Bakes wrote:
> > On 13 Sep, 22:41, Chris Rebert <c... at rebertia.com> wrote:
> >> On Sun, Sep 13, 2009 at 2:34 PM, Bakes <ba... at ymail.com> wrote:
> >>> I am using a simple python script to download my logfiles. This is on
> >>> a while loop, the logfile grows rapidly, so it is necessary for python
> >>> to start downloading the new script as soon as it has finished the
> >>> old.
> >>> It works fine (for about 20 minutes), then crashes. I have removed a
> >>> couple of excepts, and have narrowed the error down to a 'error_perm:
> >>> 550 logfile.log: The data is invalid.' error.
> >>> Does anyone know what the problem might be regarding this, and what I
> >>> might do to fix it?
> >> Including an actual code snippet and the full error traceback would help a lot.
>
> >> According tohttp://en.wikipedia.org/wiki/List_of_FTP_server_return_codes,
> >> error code 550 translates to:
> >> "Requested action not taken. File unavailable (e.g., file not found,
> >> no access)."
>
> >> Does the logfile get rotated or something, thus causing it to briefly not exist?
>
> >> It might also help if you explain how your logfile system works.
>
> >> Cheers,
> >> Chris
> >> --http://blog.rebertia.com
>
> > It's a cod4 gameserver logfile, being downloaded for a python bot to
> > parse.
>
> > The logfile is downloaded using this try/except while loop.
>
> >     while True:
> >         try:
> >             if ftp == False:
> >                 self.debug('FTP connection not active, attempting to (re)connect')
> >                 ftp = self.ftpconnect()
> >             size=os.path.getsize('games_mp.log')
> >             ftp.retrbinary('RETR ' + os.path.basename(self.ftpconfig ['path']), handleDownload, rest=size)
> >             if self.console._paused:
> >                 self.console.unpause()
> >         except:
> >             print error
> >             self.debug('Lost connection to server, pausing until updated properly, Sleeping 10 seconds')
> >             self.console.pause()
> >             try:
> >                 ftp.close()
> >                 self.debug('FTP Connection Closed')
> >             except:
> >                 self.debug('FTP does not appear to be open, so not closed')
> >             ftp = False
> >             time.sleep(10)
>
> > I can only assume that occasionally, the logfile is being written to
> > by the gameserver at the same time that it's downloading.
> > If this was the case, do you think a try: download except: sleep
> > 900msec then download loop would work?
>
> Bare excepts are almost always a bad idea because they'll catch _all_
> exceptions, both those you expect could happen and those you don't.
> Catch only those you expect.
>
> For example, if the file 'games_mp.log' doesn't exist then
> os.path.getsize('games_mp.log') will raise an exception, and if you
> forgot to import the os module then that will raise a NameError
> exception.
>
> Anyway, I can't see how you leave the loop; I'd expect something like a
> 'break' statement.
>
> And as a matter of style, I'd prefer None to False to indicate when
> there's no FTP connection (and "if not ftp" instead of "if ftp ==
> False").

I removed the try/except and saw when it failed.

I'll change those things, games_mp.log is guaranteed to be there (file
made in another script), os is imported correctly.

So, what do you think the error could be?



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