for db(status == 'pending').select():
task.update_record(status == 'processing')
success = do_long_thing_with(task)
fail
if success:
task.update_record(status = 'done')
This way, records that have a status of processing will not get pulled
in by a concurrent thread.
-Thadeus
On Tue, Dec 29, 2009 at 1:07 AM, toomim <too...@gmail.com> wrote:
> What's the best way to use web2py to process a queue of data in a cron
> job without race conditions?
>
> My code basically does this:
>
> for task in db(status != 'done').select():
> success = do_long_thing_with(task) # takes a long time, might
> fail
> if success:
> task.update_record(status = 'done')
>
> I launch this every N minutes in a cron job. But if it takes more
> than N minutes to run, the cron starts another loop in parallel and
> duplicates all calls to do_long_thing_with(task).
>
> What's the best way to fix this? It seems hard without being able to
> manually say where transactions should start with BEGIN.
>
> --
>
> You received this message because you are subscribed to the Google Groups
> "web2py-users" group.
> To post to this group, send email to web...@googlegroups.com.
> To unsubscribe from this group, send email to
> web2py+unsubscr...@googlegroups.com.
> For more options, visit this group at
> http://groups.google.com/group/web2py?hl=en.
>
>
>
--
You received this message because you are subscribed to the Google Groups
"web2py-users" group.
To post to this group, send email to web...@googlegroups.com.
To unsubscribe from this group, send email to
web2py+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/web2py?hl=en.
