[Tutor] I need an 'atomic read/ write action'

[Kent Johnson]

Tom wrote:
> So all my ideas for how to record task x as 'done', like using shelve 
> or writing a log file etc are not sufficient because, I need an 'atomic 
> read/ write action' (I think that's the jargon).

A couple of ideas:
- Michael's file lock
- lockfile is another way to lock files
http://pypi.python.org/pypi/lockfile/0.1

- you could put the tasks in a database that supports transactions
- you could run the scheduler as a single cron task rather than 
opportunistically when a user makes a request.
- you could just use cron as your scheduler directly

Kent