> Tarek Ziadé added the comment:
> 
>> If os.urandom() doesn't fail, something else will fail soon after.
> 
> the random pool can be exhausted, but this is not "soon after" I think. In Linux and Mac OS X, ulimit -n defaults to 512 and 256.

It's highly unlikely that you are every going to exhaust the CPRNG to a
point were it is no longer cryptographically secure. Thomas Ptacek
pointed me to http://security.stackexchange.com/a/3939 yesterday.

>> I agree with Antoine. Exhausting the FDs is not the problem,
> 
> Do you suggest that we should not use os.urandom on high load ?
> 
> Opening an FD on every call sounds under optimal, I am not seeing any drawback not to try to optimize that API.

The drawback is a slightly more complicated implementation that has to
deal with invalid FDs.