Re: File access denied after subprocess completion on Windows platform


There used to be a problem with subprocess fds being held by
a traceback. IIRC, the problem could be triggered by having
an except clause around a subprocess call within which something
attempted to, eg,
remove one of the affected files.

I have no subprocess call.. in this last issue. And I didn't triggered
one (disabled the Button that runs the subprocess).

try:
for line in t.splitlines():

[...]

ret = self.downloadFileToDisk(filename, do_rename)

if not ret:
print "DEBUG: Problema la download"
raise Exception()

(1) except Exception as inst:
print type(inst)
print inst.args

self.updateText.emit("EROARE: Eroare la descarcare")
self.updateStatusBar.emit("EROARE: Eroare la descaracare
fisiere")
return

Where downloadFileToDisk():

def downloadFileToDisk(self, filename, final_rename=True):
dfilename = os.path.join(saveBasePATH, filename)
sfilename = dfilename + ".part"

dfolder = os.path.dirname(sfilename)
if dfolder != "":
if not os.path.isdir(dfolder):
os.makedirs(dfolder)

try:
fp = open(sfilename, "wb")
except:
return False

curl = pycurl.Curl()

curl.setopt(pycurl.URL, baseUpdateURL + "/client/" + filename)
curl.setopt(pycurl.CONNECTTIMEOUT, 30)
curl.setopt(pycurl.NOPROGRESS, 0)
curl.setopt(pycurl.FOLLOWLOCATION, 1)
curl.setopt(pycurl.MAXREDIRS, 5)
curl.setopt(pycurl.PROGRESSFUNCTION, self.updateFileProgress)
curl.setopt(pycurl.WRITEDATA, fp)
curl.setopt(pycurl.BUFFERSIZE, 4194304)
curl.setopt(pycurl.NOSIGNAL, 1)
curl.perform()

retcode = curl.getinfo(pycurl.HTTP_CODE)

curl.close()

fp.close()

if retcode != 200:
(2) os.unlink(sfilename)
return False

self.msleep(10)

if final_rename:
os.rename(sfilename, dfilename)

return True

Without self.msleep(10), (1) catches WindowsError: file access ... blah
blah. Maybe at (2) can be an access violation, but it wasn't triggered
yet in tests. I will move the sleep after fp.close(). Yes, I know that
what it've done with raise Exception() is UGLY, since this program it's
more a quick hack solution to a problem :). Anyway the Exception that is
catched is not rised by my code (it's a WindowsError).

I'm sorry if that's a bit
of a woolly description but if you think this might be
biting you I'll dive in and look at the code. What version
of Python are you using?

Last 2.7.x. Well, if os.rename is instead a subprocess call, then it's
subprocess based. I'm new to Python but 99% I think it's a system call
:)

(That said, the fact that the behaviour varies between faster
and slower computers makes that cause unlikely. Maybe we're
back to looking at virus checkers and the like...)

On that virtual machine there is no virus checker. On the faster machine
I disabled and closed the antivirus.

--
Claudiu Nicolaie CISMARU
GNU GPG Key: http://claudiu.targujiu.net/key.gpg
T: +40 755 135455
E: claudiu@xxxxxxxxxxxxxxx, claudiu.cismaru@xxxxxxxxx

Attachment: signature.asc
Description: This is a digitally signed message part.

Relevant Pages

  • Re: Raising exception on STDIN read
    ... I would like to raise an exception any time a subprocess tries to read ... reads from STDIN... ...
    (comp.lang.python)
  • Re: Raising exception on STDIN read
    ... I would like to raise an exception any time a subprocess tries to read from STDIN: ... The problem in my actual program is that the user can change the latex command and the compiler options, so I can't guarantee that the latex compiler is being run in batchmode or nonstopmode. ... So, ideally, I want to enforce that the subprocess is non-interactive by trowing an exception if it does ask for input. ...
    (comp.lang.python)
  • Re: Raising exception on STDIN read
    ... I would like to raise an exception any time a subprocess tries to read ... reads from STDIN... ...
    (comp.lang.python)
  • Re: Raising exception on STDIN read
    ... I would like to raise an exception any time a subprocess tries to read ... reads from STDIN... ...
    (comp.lang.python)