[Python-Help] os listdir access denied when run as a service

[Danny Yoo]

On Thu, 25 May 2006, Thomas Thomas wrote:


> I am trying to access a mapped network drive folder. everything works 
> fine normally. But when i run the application as service I am getting 
> the error

The error is on the line:

     for filename in os.listdir(folder):#line 25

and I have to assume that the bad call here is to os.listdir().



What's the particular input that's being sent to os.listdir() at the point 
of failure?  As far as I can tell, the error message:

> Traceback (most recent call last):
>  File "docBoxApp.py", line 129, in ?
>  File "core\PollFiles.pyc", line 332, in doPoll
>  File "core\PollFiles.pyc", line 47, in createFileList
>  File "core\PollFiles.pyc", line 25, in addFolderFiles
> WindowsError: [Errno 5] Access is denied:'G:\\DT Hot Folder test/*.*'

suggests that 'G:\\DT Hot Folder test/*.*' might be the folder being 
passed.  If so, that could be the problem, since os.listdir takes the name 
of a directory: it does not take a file glob.


Can you check to see what 'folder' is being passed into your program in 
the context of a file service?  The problem may simply be bad input.


We can check early on this by programming a bit defensively, mandating 
that on entry to addFolderFiles that 'folder' must be an existing 
directory:

########################################
def addFolderFiles(folder, filelist=[]):
     assert os.path.isdir(folder)
     ...
########################################

in which case, if we get past the assertion, we'll be able to at least 
know that we're getting in semi-good input.



One other note: it is not recommended that we use a list as a default 
parameter value.  That value will be shared among all calls to 
addFolderFiles, so we will see side effects.  See the "Important Warning" 
in:

http://docs.python.org/tut/node6.html#SECTION006710000000000000000