Re: [hibernate-dev] multi-tenancy and ConnectionProvider

Well I think I am leaning towards a "parameter object" no matter what we do otherwise. So call this param object interface ConnectionOptions. It would have a single method today (err, tomorrow when I write all this :) to get the tenant id. The tenant id is really associated with the session. Either session implements that interface or hands it off to a delegate it manages, but thats the "scope"... the session. So in your examnple, you would inject the entitymanager's session with the proper tenant id. Ideally I want this to be specified up front when the session is opended to make sure there is no possibility of changing it mid- stream, but that further relies on http://opensource.atlassian.com/projects/hibernate/browse/HHH-2860 Anyway, in thinking about this sme more I think the way I really like is this: 1) ConnectionProvider remains as is 2) introduce a new provider contract (names as always are preliminary): public interface SpecializedConnectionProvider extends ConnectionProvider { public static interface ConnectionOptions { public String getTenantIdentifier(); } public Connection getSpecializedConnection(ConnectionOptions); public void releaseSpecializedConnection(ConnectionOptions, Connection); } Having SpecializedConnectionProvider extend ConnectionProvider addressed another issue I encountered when implementing this. How do you account for situations where you need *some* connection? Like when reading java.sql.DatabaseMetaData on "startup". The other option for that is to not have SpecializedConnectionProvider extend ConnectionProvider (so they are back to distinct hierarchies) and adding an extra method to SpecializedConnectionProvider. This additional method would either give access to a connection with out providing tenant information or if obtaining java.sql.DatabaseMetaData is deemed the only acceptable use case there then just have a method to scrape that info passing back DatabaseMetaData is not an option if that is the decision because of java.sql.DatabaseMetaData#getConnection Also, I was not sure if there is really a need for a specialized "release this connection" method in the case where SpecializedConnectionProvider extends ConnectionProvider. There is still the ConnectionProvider#closeConnection method. Now obviously if the herarchies are distinct we would need release capability on both... On Wednesday, March 23, 2011, at 04:24 pm, Chris Bredesen wrote: > But 3 is how it's done today since we don't have the other solutions. > So yeah it's magical, but people do manage to make it work. I will > concede that it is not always perceived as straightforward, however. > > Something to think about in the grander scheme of things is how someone > would deal with obtaining a tenant-specific connection when resource > injection is in use. #3 solves this but what about #1 and #2? There > are some pretty neat things that I can envision wrt CDI but I haven't > thought through what the implementations would look like. > > @Inject @TenantSpecific @UserDatabase private EntityManager em; > > How would you drill the tenant information into the CP? > > -CB > > On 03/23/2011 04:25 PM, Adam Warski wrote: > > I think for a user the best option (easiest to understand) would be 1). > > > > 3) is too magical. 2) is putting everything in one sack. > > > > Adam > > > > On Mar 22, 2011, at 10:21 PM, Steve Ebersole wrote: > >> reference > >> http://opensource.atlassian.com/projects/hibernate/browse/HHH-5697 > >> > >> For multi-tenancy implemented by sepaerate schema we need the ability > >> to tell the ConnectionProvider about the tenant for the given > >> getConnection() request. I really see 3 approaches to this: > >> > >> 1) Have 2 hierarchies here. The current ConnectionProvider contract > >> remains the same. Add a new MultiTenantConnectionProvider with > >> methods accounting for tenant > >> 2) Just alter the ConnectionProvider contract to pass information in. > >> If we go this route I prefer the "parameter object" pattern where we > >> pass in ConnectionOptions interface (see issue). > >> 3) Use contextual lookup. ConnentionProviders interested in (or > >> capable of understanding) mulit-tenancy would perform some kind of > >> "contextual" (ThreadLocal, etc) lookup for the needed information. > >> > >> Thoughts? Discussions? > >> > >> --- > >> Steve Ebersole&lt;steve(a)hibernate.org&gt; > >> http://hibernate.org > >> _______________________________________________ > >> hibernate-dev mailing list > >> hibernate-dev(a)lists.jboss.org > >> https://lists.jboss.org/mailman/listinfo/hibernate-dev > > _______________________________________________ > hibernate-dev mailing list > hibernate-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/hibernate-dev --- Steve Ebersole <steve(a)hibernate.org&gt; http://hibernate.org