3

See update at the end.

I am using Ubuntu Linux 11.10, Python 3.

I wrote a Python script which converts some Qt *.ui files to *.py using pyuic4. Then i want to compile the obtained *.py file to *.pyc and delete the *.py file.

For some reason when i delete a converted *.py file, the *.pyc version is also deleted:

try: command = 'pyuic4 -o /home/vic/ui_form.py /home/vic/form.ui' output = subprocess.check_output(command, shell= True, stderr= subprocess.STDOUT) except subprocess.CalledProcessError as e: print('Failed:', e.output) else: print('Converted %s to %s' % (source, targetName)) # convert *.py to *.pyc and delete the source source = '/home/vic/ui_form.py' target = source + 'c' # py -> pyc py_compile.compile(source, target) #shutil.copy(target, target + '_') # if uncommented - the *.pyc_ file remains os.remove(source) # if commented - both *.py and *.pyc files remain, otherwise both deleted (?)

I don't know what's happening (see the comments in the code for additional info).

I thought i would have a hint if i find WHO deletes the file - maybe it's pyuic4?

I there a possibility to monitor which process deletes a file?

UPDATE:

I was debugging step by step. After executing os.remove(source) both files (*.py - source, and *.pyc) are deleted.

Could this be some Python behavior?

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  • source=target - so target is your .py initially? Where does this get initialised? And why do you have target and targetName? Commented Oct 27, 2011 at 10:38
  • sorry i took this from a bigger code. i will simplify this. Commented Oct 27, 2011 at 10:40
  • Watch out copy-paste when coding. A lot of bugs come from copy-pasting code without really focusing on what's being done. Use generic modules instead of copy-pasting. Also this IMHO fits better in StackOverflow. Commented Oct 27, 2011 at 10:59
  • Use strace -f and search for unlink in the log. Commented Oct 27, 2011 at 11:16
  • strace -f helped - it showed the unlink calls, but only *.py files where deleted. could there be a race condition, that compiling *.py -> *.pyc is not finished while *.py is being deleted and *.pyc is also deleted by OS? Commented Oct 27, 2011 at 11:49

4 Answers 4

Reset to default
6

You can set sysctl -w vm.block_dump=1 to see every file system action in dmesg. (high volume, so disable again afterwards)

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2

I was going crazy all the day with this issue, and, as it often happens, the solution was near, but of a different kind:

I have this project open in Eclipse. When Eclipse is open it tracks the creation of new *.py files (from *.ui or *qrc). Then Eclipse automatically adds them to the project.

When the script converts *.py files to *.pyc and deletes the *.py files - Eclipse also tracks this and carefully deletes the corresponding *.pyc files.

So this is it.

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1

You may use inotify to detect filesystem activity. See the manual. Quoting the manual:

 IN_DELETE File/directory deleted from watched directory (*). IN_DELETE_SELF Watched file/directory was itself deleted.

Not sure if you can get who deleted it. Another idea:

chattr +i test.py

and see if some command tries to unsuccessfully delete it (and gives an error message).

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0

You could try using auditd. I haven't tried it, but it might be helpful.

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