We've had a home-brewed solution for a while. PendingNotification(s) that get processed by a cron task that runs every minute. The PendingNotification has all the data the cron task needs to execute it.
Actually, for a while, GAE didn't even have cron tasks. So we were kicking off stuff using silent ajax calls from clients.
agreed. ever since i started playing around with GAE, i keep getting disappointed at the fine print of its limitations. its almost useless to do any kind of meaningful reporting from the datastore and i'm sure even this task api as you mentioned will keep hammering away at my sanity.
but with that said, i still play with it since i have faith it'll mature into a full platform. and if nothing else, it's a free hosting service for experimental websites, bringing down the barrier to entry officially to zero.
The 10.000 insertions per day is the real limit for now. Otherwise you could execute 24 (hours) * 3600 (s/h) * 10 (tasks/s) * 11 (queues, 1 default + 10 custom queues) = 9504000 tasks per day, which is not bad at all. But as you can only create 10k tasks per day, you cannot even approach this limit.
Actually, for a while, GAE didn't even have cron tasks. So we were kicking off stuff using silent ajax calls from clients.