Schema-base multi-tenancy example

[col-panic]

Concerning the Support for Multitenancy google-group discussion I implemented a concise example - this PR.

I would very much appreciate any comments on the code done here. It is not a prior target to get this PR included - but to have an appropriate discussion point for persons interested in this functionality.

[jamesagnew]

This is really neat! Nice work.

I guess my main comment would be that it would be preferable to replace the tenant identification Filter with an implementation of ITenantIdentificationStrategy. This has a couple of advantages:

• It is the HAPI FHIR native way of doing multitenancy, which means it'll play nicely with AuthorizationInterceptor and potentially other interceptors that are aware of it
• It can be registered with the server at runtime, meaning that it could be enabled purely based on properties in the hapi.properties file

One other thought- it'd probably be good for this to have a unit test since it seems like something that will fail into disrepair pretty fast if it's not tested regularly. That's tough though of course, since that one has to work on Derby and I don't think Derby supports the USE clause you're using with MySQL.

Presumably we'd have to use a separate schema (i.e. a different JDBC URL) per tenant on Derby..

[col-panic]

Thanks for your comment!

I don't see how FHIR itself, resp. ITenantIdentificationStrategy would fit to this scenario, if the "tenant-switch" is already done on JDBC resp. connection level. HAPI-FHIR shouldn't even bother here, no? I mean every request just operates against a totally different scheme.

I see that this patch is only working for mysql by now, for derby you would have to have a separate connection per tenant, which you then hand out. I'll take a look whether I can augment the starter with this scenario.

If HAPI-FHIR was to do the tenant handling, wouldn't it be only able to do single-database-multitenancy by means of tenant discriminators such that the SQL requests may consider them? ITenantIdentificationStrategy currently does not offer me any possibility to replace the underlying JDBC connection - but only to change the servers access url.

Unit tests - certainly - as soon as all discussion is done ;)

[jkiddo]

@col-panic / @jamesagnew is this still relevant?

[col-panic]

@jkiddo this was a prototype for a project that was not done. So for me it is not relevant, maybe it would be interesting to keep it if another developer runs into this?

[tsun424]

Hi @col-panic , thanks for creating this PR and keeping it open for other developers. I wonder if you've ever implemented this schema-based multi-tenancy solution in any production environment, if you did, have you had any issues for this solution? Thank you.

[col-panic]

@tsun424 I never really implemented this solution. Management decided to change direction ;)

[tsun424]

Hi @col-panic thanks very much for your reply 👍

@tsun424 I never really implemented this solution. Management decided to change direction ;)

[patrick-werner]

as this was only a prototype, im closing this PR