google appstore, how to split fees per datastore namespace

Question

I'd like to make a GAE app multi-tenant to cater to different clients (companies), database namespaces seems like a GAE endorsed solution. Is there a meaningful way to split GAE fees among client/namespaces? GAE costs for app are mainly depends on user activities - backend instances up time, because new instances are created or (after 15 min delay) terminated proportionally to the server load, not total volume of data user has or created. Ideally the way the fees are split should be meaningful and could be explained to the clients.

I guess the most fair fee splitting solution is just create a new app for a new client, so all costs reported separately, yet total cost will grow up, I expect few apps running on same instances will use server resources more economically.

Answer 1

Every app engine request is logged with a rough estimated cost measurement. It is possible to log the namespace/client associated with every request and query the logs to add up the estimated instance costs for that namespace. Note that the estimated cost field is deprecated and may be inaccurate. It is mostly useful as a rough guide to the proportion of instance cost associated with each client.

As far as datastore pricing goes, the cloud console will tell you how much data has been stored in each namespace, and you can calculate costs from that. For reads/writes, we have set up a logging system to help us track reads and writes per namespace (i.e. every request tracks the number of datastore reads and writes it does in each namespace and logs these numbers at the end of the request).

The bottom line is that with some investments into infrastructure and logging, it is possible to roughly track costs per namespace. But no, App Engine does not make this easy, and it may be impossible to calculate very accurate cost estimates.