account(s) management over multiple tenants

i have an app with multiple tenants on GAE.

over the 'master' (which is a tenant on its own) i let people register and create a subapp/tenant where the creator is the owner of the app.

what is the best way to manage the user accounts?

lets say USER_A creates APP_A and USER_B creates APP_B. so there are 2 users and 2 apps where each user is owner to the app it created and does not have access to the other users app. now USER_B wants to give access to the other user on his app.

what is the best way to model this situation.

should i store members in a completely separate namespace and validate the users session by switching constantly between namespaces?

i think the best pla开发者_如何学Cce to keep what permissions a specific user has on an app is on the actual app tenant rather than the USER object.

any tips or best practices?

thank you

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If 'user identity' can span tenants (your apps), then keep user entities in a common namespace (the default namespace works fine for that, and that's the default when a request begins). Anything specific to a tenant (e.g., what authorization a user identity has for a specific tenant) can be stored where it is most convenient. I find that putting it in the tenant's namespace simplifies queries that would otherwise have to specify that or filter it out.