While the task name thing should generally work, they don't provide a guarantee that inserting the task won't succeed more than once. Also, I don't particularly want to have to add a task to check if it is inserted. There is also the problem of tombstoning names, so I would need to come up with unique task names that could be computed by the cron job.
http://code.google.com/appengine/docs/python/taskqueue/overview.html#Worker_URLs_and_Task_Names I thought about using a heartbeat to check but I'm a bit afraid of contention issues. The heartbeat option seems like it would be the most straight forward though. Ian On Mon, Nov 22, 2010 at 8:27 AM, vlad <[email protected]> wrote: > Agree with Robert named tasks are the way to go. I have a similar > requirements - have a long running state machine implemented as > chained tasks. Once I worked out transactional issues and added > "choke" points to prevent fork bomb it has been running ok for over 1 > week now. Clarification, by "running ok" I meant that task flow is > sustained in presence of occasional datastore and memcache errors. You > task handlers and app as a whole should still deal with idempotancy > issues arising from errors. > > On Nov 21, 5:07 am, Remigius <[email protected]> wrote: > > Ian, > > > > It does not look like there's a facility to look up queued tasks in > > the task queue API. Instead you could use a heartbeat in the data > > store (i.e. save an entity with a timestamp each time the task queue > > task runs) that is checked by the cron job. > > > > Cheers, Remigius. > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- Ian http://www.ianlewis.org/ -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
