[keycloak-user] ProviderFactory::postInit + transactions = startup failure

[Dmitry Telegin]

Hi Marek,

Thanks for the hint, looks very reasonable. I think the
PostMigrationEvent approach is more suitable for heavyweight stuff like
checking and creating database entries etc., while lazyInit is good for
more lightweight tasks like opening connections etc.

However, there's an interesting case when the postInit method is called
on hot (re)deploy (no PostMigrationEvent obviously) *and* some
heavyweight stuff needs to be done right away. (ATM postInit is not
called on hot deploy, but I hope that will be fixed soon, see KEYCLOAK-
5131 and PR #4282.)
Luckily, in this case transactions just work, so everything could be
done straightforwardly. The only question is how to distinguish between
server startup and hot (re)deploy inside postInit. There are some
indirect signs like thread name, presence/absence of specific JNDI
entries etc., but this seems hacky. Any suggestions?

Cheers,
Dmitry

> Hi,
> 
> I think it's not good to directly start transactions from postInit. 
> Among the issues you mentioned, various initial steps (eg. migration 
> from previous version, export/import) may not be yet finished at
> this 
> stage. Probably you can either:
> - Register listener for PostMigrationEvent in your postInit. See the 
> testsuite/integration-arquillian/servers/auth-
> server/services/testsuite-
> providers/src/main/java/org/keycloak/testsuite/authentication/PushBut
> tonAuthenticator.java 
> for inspiration.
> - Use the pattern with "lazyInit" like for example here 
> https://github.com/keycloak/keycloak/blob/master/model/jpa/src/main/j
> ava/org/keycloak/connections/jpa/DefaultJpaConnectionProviderFactory.
> java#L78 
> , which is called 1st time before your provider is actually needed.
> 
> Maybe we can improve by provide more callback methods to 
> ProviderFactory/Provider to avoid the lazyInit pattern directly in 
> providers, but rather integrate it better with the Provider
> framework. 
> But for now, I think that some of the workaround above should work
> for 
> you IMO.
> 
> Marek
> 
> On 03/07/17 03:50, Dmitry Telegin wrote:
> > https://issues.jboss.org/browse/KEYCLOAK-5132
> > 
> > Meanwhile I've found a workaround - just run a transaction in a new
> > thread. However, this should be a "managed thread" - see issue
> > details
> > & comments for more info.
> > 
> > В Wed, 28/06/2017 в 21:18 +0300, Dmitry Telegin пишет:
> > > Hi,
> > > 
> > > (TL;DR) if a KeycloakTransaction is opened from
> > > ProviderFactory::postInit, sometimes the transaction is already
> > > active
> > > on the underlying
> > > org.jboss.jca.adapters.jdbc.local.LocalManagedConnection, which
> > > leads
> > > to errors.
> > > 
> > > (full version) I think it's essential for the providers to be
> > > able to
> > > access realm data in postInit(). For that, a transaction is
> > > required;
> > > using KeycloakModelUtils.runJobInTransaction() is a convenient
> > > method
> > > to do that:
> > > 
> > >      @Override
> > >      public void postInit(KeycloakSessionFactory factory) {
> > >          KeycloakModelUtils.runJobInTransaction(factory,
> > > (KeycloakSession session) -> {
> > >              List<RealmModel> realms =
> > > session.realms().getRealms();
> > >              // do stuff
> > >          });
> > >      }
> > > 
> > > When such a provider is deployed, in about half of cases Keycloak
> > > fails
> > > to start due to the following exception:
> > > 
> > > java.sql.SQLException: IJ031017: You cannot set autocommit during
> > > a
> > > managed transaction
> > > 
> > > (see full stacktrace here https://pastebin.com/ETtPqXQk)
> > > 
> > > I've managed to track it down to something that looks like
> > > transaction
> > > clash over a single instance of
> > > org.jboss.jca.adapters.jdbc.local.LocalManagedConnection. What
> > > happens
> > > is that the two treads at the same time begin two
> > > KeycloakTransactions
> > > which end up with the same instance of LocalManagedConnection.
> > > The
> > > above exception results from the second begin() call.
> > > 
> > > There's a system property called
> > > "ironjacamar.jdbc.ignoreautocommit"
> > > that allows to ignore the situation, but I think it's dangerous
> > > because
> > > it doesn't eliminate the transaction clash, just suppresses the
> > > check.
> > > If I'm not mistaken, this began to happen around Keycloak 2.2.x,
> > > which
> > > coincides with the changes to Keycloak transaction management.
> > > That
> > > said, do I need now some additional transaction coordination with
> > > the
> > > rest of Keycloak, or is it a bug? If former, how do I do that? If
> > > latter, how do we fix it?
> > > 
> > > I hope we'll sort it out, since the ability to access the data at
> > > every
> > > phase of provider's lifecycle seems something fundamental to me.
> > > 
> > > Regards,
> > > Dmitry
> > > _______________________________________________
> > > keycloak-user mailing list
> > > keycloak-user at lists.jboss.org
> > > https://lists.jboss.org/mailman/listinfo/keycloak-user
> > 
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