Hi there, I'm writing a game backend in app engine where progress in each game is described by timestamped events. So any time a player takes a turn or types a chat message it generates one or more events, each timestamped using datetime.utcnow(). Each game and its data form an entity group in the datastore, and each user can have multiple games in progress at any given time. On the client side the game keeps track of the timestamp of the last event it's seen (across *all* the user's games) and periodically requests all newer events.
But of course GAE is a distributed system and utcnow() is not going to be consistent across different nodes of the system, so this won't work. Eventually there will be two near-simultaneous events in different games that get written to the datastore in the "wrong" order and one of them will never be seen because it's "older" than the "newest" event. So what's the right way to solve this kind of problem? I like the concept of a global event stream for each user, but maybe I have to abandon that model and use one event stream per game. Or maybe it would be better to assume that the clocks won't be *too* far off and request events with timestamps greater than N seconds before the last event the client's seen. I'd be grateful for any recommendations or suggestions. Thanks, -n8 -- http://n8gray.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 -~----------~----~----~----~------~----~------~--~---
