Race condition when generating .pyc files

[Bruno Desthuilliers]

yogamatt1970 at gmail.com a écrit :
> I have a large body of Python code which runs on many different (Unix)
> machines concurrently.  Part of the code lives in one place, but most
> of it lives in directories which I find at runtime.  I only have one
> copy of each Python source file and I think I'm hitting a race
> condition where two hosts attempt to import the same module at the
> same time.  My import fails on one of the machines and the following
> exception is thrown:
> EOFError: EOF read where object expected
> My hypothesis is that there's contention between the two (or more)
> hosts when the module's .pyc file is generated.
> 
> Possible solutions I see:
> 1) Running a cron job before my code executes which compiles all the
> python source first.

If you package your apps using setup, pyc should be automatically 
generated. Don't know if it can apply to your problem. But surely I'd go 
this way (ie : automating pyc creation one way or another).

> 2) Making separate copies of all the .py files for each host running
> the code - I'd rather not do this, it seems like a big pain.

yeps.

> 3) Inhibiting the generation of .pyc files altogether if that's even
> possible - I saw a PEP for a possible -R flag (http://www.python.org/
> dev/peps/pep-0304/) but I don't think it has been added to a released
> version of Python yet plus I am stuck with Python 2.4 for the time
> being.

Not having pyc means the modules will have to be recompiled on each 
import. Not sure this is what you want.