On 07/11/2013 12:57 AM, Jason Friedman wrote:
Other than using a database, what are my options for allowing two processes
to edit the same file at the same time? When I say same time, I can accept
delays. I considered lock files, but I cannot conceive of how I avoid race
conditions.
In general, no. That's what a database is for.
Now, you presumably have some reason to avoid database, but in its stead
you have to specify some other limitations. To start with, what do you
mean by "the same time"? If each process can modify the entire file,
then there's no point in one process reading the file at all until it
has the lock. So the mechanism would be
1) wait till you can acquire the lock
2) open the file, read it, modify it, flush and close
3) release the lock
To come up with an appropriate lock, it'd be nice to start by specifying
the entire environment. Which Python, which OS? Are the two processes
on the same CPU, what's the file system, and is it locally mounted?
--
DaveA
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