Concurrent writes to the same file

[Jason Friedman]

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.

 

[Nobody]

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.

What do you mean by "edit"? Overwriting bytes and appending bytes are
simple enough, but inserting or deleting bytes such that subsequent bytes
change their offsets is harder.

I considered lock files,

Well, you shouldn't have, unless you're targeting a platform which doesn't
support file locks (are there any left?).

but I cannot conceive of how I avoid race conditions.

By using locks. E.g. fcntl.lockf() or msvcrt.locking().