[keycloak-dev] Thinking about a change to providers
Marek Posolda
mposolda at redhat.com
Fri Jun 24 00:21:23 EDT 2016
On 23/06/16 15:40, Stian Thorgersen wrote:
>
>
> On 23 June 2016 at 15:33, Marek Posolda <mposolda at redhat.com
> <mailto:mposolda at redhat.com>> wrote:
>
> On 23/06/16 14:28, Stian Thorgersen wrote:
>>
>>
>> On 23 June 2016 at 14:19, Marek Posolda <mposolda at redhat.com
>> <mailto:mposolda at redhat.com>> wrote:
>>
>> +1 on having "invalidateProvider" method.
>>
>> For the other stuff, we already have the first 2
>> "getProvider" methods, so the new stuff will be the methods
>> with "String instanceId" parameter, right?
>>
>>
>> Yes, I just included the two existing methods to point out that
>> they will still be there.
>>
>>
>> We already discuss adding the "String instanceId" . Now when
>> thinking more, it looks that it is not so convenient.
>>
>> When adding again UserFederation SPI as an example:
>>
>> - UserFederationProviderFactory needs
>> UserFederationProviderModel to create instance of
>> UserFederationProvider
>> - So factory needs to lookup model from cache/db. Hence the
>> instanceId would need to be compound of something like:
>> <REALM-UUID>::<USER-FEDERATION-PROVIDER-MODEL-ID>
>> That's because to lookup UserFederationProviderModel, you
>> first need RealmModel and then find the
>> UserFederationProviderModel by it's ID within the realm.
>>
>> You may admit that RealmModel is available on
>> KeycloakContext. However I don't think that we can rely on
>> it. KeycloakContext is available in REST requests, but in
>> some other cases (ie. ExportImport, periodic tasks etc), it's
>> not available. Caller usually have the RealmModel and he can
>> manually set it to KeycloakContext before calling
>> session.getProvider, however that doesn't look like good
>> approach to me and should be rather avoided. So in shortcut,
>> we shouldn't rely on realm being available in KeycloakContext
>> IMO.
>>
>>
>> Going forward we should rely on the realm being available in
>> KeycloakContext IMO. The whole purpose of it is so we don't have
>> to pass details around all the time, including the realm.
>>
>> I see two options to it:
>>
>> * Don't require the realm to load provider config. If instances
>> ids are UUIDs this would work, but I don't think they always are
>> right?
> Even if they are just UUID, we will require to refactor model and
> have all the models lookup methods (e.g.
> "getUserFederationPRoviderModel", "getIdentityProviderModel" )
> available globally on RealmProvider rather than on RealmModel. Not
> sure if it's very good, especially since in admin console, you
> create providers per particular realm.
>> * Add RealmModel to the lookup, so it becomes:
>> getProvider(Class<T> clazz, String providerId, RealModel realm,
>> String instanceId)
>> That would also require a invalidateProviders(RealmModel realm)
>> that can clear all provider instances for a specific realm
> Not sure adding RealmModel is sufficient... Some providers might
> not be scoped per-realm but rather per-client though. For example
> recently added authz based ResourceServer is scoped per client, so
> I can imagine it can be valid use-case to have providers scoped
> per-client as well.
>
>
> Not sure why a provider should be scoped per-client. A ResourceServer
> in either case it's an internal thing and there should be a
> getResourceServer(ClientModel client) rather than
> getProvider(ResourceServer..). Not sure what the code does now though.
>
>
>>
>> The logic for parse the "instanceId" and retrieve
>> UserFederationProviderModel from DB would be boilerplate code
>> same to all UserFederationProviderFactory impls.
>>
>>
>> With that in mind, it really seems to me that instead of
>> "String instanceId", it may work better to have some common
>> configuration class like "ProviderModel" . Then signature
>> will look like:
>>
>> * getProvider(Class<T> clazz, String providerId,
>> ProviderModel model)
>>
>> All the model subclasses (UserFederationProviderModel,
>> IdentityProviderModel, PasswordPolicyModel ...) will be
>> subclasses of ProviderModel
>>
>>
>> I don't like that at all as it requires loading and retrieving
>> the model to be able to get the instance. It should be the
>> responsibility of the factory and provider framework to be able
>> to do that, not the code that wants to use the provider.
> Well, I don't see that as an issue, but rather an advantage. It's
> better if model is loaded by caller rather than an implementation.
> So the custom UserFederationProviderFactory (or
> IdentityProviderFactory) implemented by customers don't need to
> contain same code for lookup the model based on instanceId String.
>
>
> It's basic principals of dependency injection and loosely coupling to
> not require knowing how to create something to be able to use it. I
> strongly disagree that the calling code needs to know how to load the
> config. There are multiple places that may need to use a provider,
> which would then require all those places to be able to load the
> config. Further, not all providers may want to use the model directly.
> If it's up to the factory itself to load the config the config can be
> located elsewhere.
Sure, the caller shouldn't be required to know how to create provider,
it's the responsibility of factory. But the caller should know what it
wants. And calling code (Keycloak) always knows model in all cases I can
think of.
For example, in case of UserFederation the workflow is like:
- Admin creates some user federation provider (eg. ldap) in admin
console. The model is saved to Keycloak db
- Then some user "john" wants to login.
- Keycloak (UserFederationManager) needs to load all the
UserFederationProviderModel from DB as the providerId is saved on the
model. Then when it knows the providerId is "ldap", it can finally call
session.getProvider and instantiate provider based on that.
Similarly when some user has "federationLink" on him, it points to the
ID of UserFederationProviderModel. So you first need to load this model
to know the providerId.
It's very similar to IdentityProvider. When you click on login screen to
"Login with 3rdPartyOidc", Keycloak first needs to load the
IdentityProviderModel by alias "3rd-party-oidc" and then see that
providerId is "oidc", so it can call session.getProvider to retrieve
the IdentityProvider implementation ( OIDCIdentityPRovider ).
We have the generic mechanism to create provider models in admin
console and the key/value pairs, which are saved as part of model.
People are not required to use this if their implementation doesn't need
any metadata configured through keycloak admin console (eg. someone can
store all metadata about their UserFederation provider implementation
into their private DB or into known property file in filesystem etc),
and then they don't need model. But then they also don't need instanceId.
Honestly ATM, I can't see any benefit in having "String instanceId"
instead of "ProviderModel providerModel" . Just one disadvantage that
factory would always need to download model, which the caller already
knows. However, maybe if you do the POC based on instanceId, I will see
that I am wrong...;)
Marek
>
>
>
> Marek
>>
>>
>> Marek
>>
>>
>> On 23/06/16 12:01, Stian Thorgersen wrote:
>>> Currently it's expected that the factory is application
>>> scoped, while provider instances are request scoped.
>>> Factories can if they want return the same instance for
>>> provider to make it application scoped.
>>>
>>> This works as long as config is server-wide, but not if
>>> there are config per-realm or even multiple different
>>> instances per-realm. This applies to for example User
>>> Federation SPI (multiple per-realm), Password Hashing SPI
>>> (one per-realm), etc.
>>>
>>> Currently the User Federation SPI creates and manages
>>> instances outside of the session factory and session, which
>>> results in multiple instances created per-request, not all
>>> being closed properly, etc..
>>>
>>> With that in mind I'd like to change the provider factories
>>> so that there can be multiple provider factory instances.
>>> It's not completely figured out, but I wanted to discuss it
>>> before I start a POC around it.
>>>
>>> We'd have the following methods on KeycloakSession:
>>>
>>> * getProvider(Class<T> clazz, Provider.class) - returns
>>> default provider
>>> * getProvider(Class<T> clazz, Provider.class, String
>>> providerId) - returns a specific provider, with the default
>>> config
>>> * getProvider(Class<T> clazz, Provider.class, String
>>> providerId, String instanceId) - returns a specific
>>> provider, with the specific config
>>>
>>> We'd also add a method:
>>>
>>> * invalidateProvider(Class<T> clazz, Provider.class, String
>>> providerId, String instanceId) - this would be called when
>>> the config for a specific provider instance is updated
>>>
>>> Behind the covers the instances would be maintained. Each
>>> provider factory would internally be responsible to retrieve
>>> config and cache config for instances.
>>>
>>> Does this sound like an idea worth pursuing? I'd like to try
>>> it out on the PasswordPolicy SPI first.
>>>
>>>
>>> _______________________________________________
>>> keycloak-dev mailing list
>>> keycloak-dev at lists.jboss.org
>>> <mailto:keycloak-dev at lists.jboss.org>
>>> https://lists.jboss.org/mailman/listinfo/keycloak-dev
>>
>>
>
>
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