Race condition when generating .pyc files

Gerhard Häring gh at ghaering.de
Tue Oct 7 17:59:24 CEST 2008

yogamatt1970 at gmail.com wrote:
> 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.
> 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.
> 3) Inhibiting the generation of .pyc files altogether if that's even
> possible [...]

If you don't want pyc files to be created, you could set Unix 
permissions such that Python cannot write to the directory.

-- Gerhard

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