[keycloak-dev] in-memory only federated users

[Bill Burke]

Either we redo the federation SPI or work with the current one.

It is just not as simple as you state.  You can't just chain in a 
generic InMemoryProvider.  Federation needs to be able to proxy the 
UserModel so that it can handle write methods if it wants to.  Or 
delegate lookup of certain things to LDAP.  Also, UserFederationManager 
has to be first in the chain so that if something is found in cache, it 
can let the federation provider proxy the cache if it wants to.

What we need is a special interface for the cache:

cache.cacheUser(UserModel user);

The cache would also work with UserFederationManager rather than a 
generic UserProvider. UserFederationManager would gain methods like:
UserFederationManager.getUncachedUserById() which the cache would 
invoke.  UserFederationManager would break down the user id and either 
know it was local storage or something that would have to be delegated 
to a UserProvider.





On 12/3/2015 10:32 AM, Marek Posolda wrote:
> IMO the more important use-case that in-memory federated users is the
> caching of federated users.
>
> Currently if you call: session.users().getUserById() and the user with
> ID "123" is LDAP (or other federationProvider) user, there is always
> call to UserFederationProvider.validateAndProxy , which results in LDAP
> query.
>
> If we introduce the chaining of UserProvider (something I already
> proposed earlier), you can switch UserFederationProvider with cache, so
> you will have:
> cache => userFederationManager => JPA
>
> instead of current:
>
> userFederationManager => cache => JPA
>
>
> With that in mind, we can easily implement in-memory as another
> implementation of UserProvider, which will hold users purely in-memory.
> Our current DefaultCacheUserProvider always require delegate to call
> write operations. But this in-memory provider would be something
> different. It won't use any delegate as it will be in the end of the
> chain. So for in-memory federation you will just configure:
>
> userFederationManager => inMemoryProvider
>
> and you're done. No needs for special ID handling or something like that.
>
> With chaining of UserProvider we have biggest flexibility for various
> needs IMO. That's why I would rather go this way TBH.
> Marek
>
> On 02/12/15 17:48, Bill Burke wrote:
>> I'm looking into in-memory only no-import federated users.  What we
>> would want to do is allow the UserFederationProvider to create an
>> in-memory UserModel and allow for that UserModel to be cached via our
>> current architecture.
>>
>> The current design assumes that all federated users are imported.  This
>> includes our caching layer too!  To add to that, the user isn't cached
>> until the 2nd request i.e.:
>>
>> 1. username/password page would hit the UserFederationProvider and the
>> user would be imported into Keycloak.  This imported user is not cached,
>> only imported into the database for this request's KeycloakSession
>> 2. OTP Page or code 2 token would then want to lookup the user by id as
>> that is what is stored in the ClientSession.  It would hit the keycloak
>> database as it is not cached yet.  This lookup loads the cache for the user.
>>
>> Getting in-memory zero-import to work is even more tricky.  The issue is
>> that ClientSession and UserSession need to lookup clients by id.  If the
>> user is not in cache, then the cache needs to lookup the user by id
>> within storage.  This lookup also needs to happen if a write operation
>> is performed on a cache user (getDelegateForUpdate()).  So, Keycloak
>> needs to know that that ID is not in local storage and must be looked up
>> from a fed provider.  The ID must be formed so that the provider fed
>> provider can resolve the lookup.  I could use a URI for the ID i.e.
>>
>> fed:{providerId}:{login-name}
>>
>> The problem with this is that this id would need to be larger than 36
>> characters which is the current column size for UserEntity.id and any
>> other table that references users.   I could possibly do:
>>
>> fed:{providerAlias}:{login-name}
>>
>> But its quite possible that combination would be larger than 36
>> characters.  We could also just shrink it to:
>>
>> fed:{login-name}
>>
>> But then we would have to iterate over every federation provider to find
>> and load the user.
>>
>> So in summary:
>> * IDs need to expand from 36 characters to something larger. (255
>> maybe).  Don't some DBs have constraints on string primary key size?  DB
>> scripts could possibly be
>> * CachedUserProvider and UserFederationManager interfaces would need to
>> be refactored
>> * I don't think UserFederationProvider interface would need to change.
>> But users would have to code for in-memory rather than throwing a switch
>> to just turn it on.
>>
>>
>>
>

-- 
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com