[keycloak-dev] Thinking about a change to providers

[Marek Posolda]

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.
>
>
>     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.

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.
>>
>>
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>
>

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