API: Add a config nessie.client-api-version

[ajantha-bhat]

needed for exposing client API version at Iceberg side: apache/iceberg#6712

[dimas-b]

I suppose for the sake of consistency we should respect this option in the Nessie client builder. For example, automatically choose/validate the API class during client construction when it is set.

[dimas-b]

Specifically, I suppose with nessie.client-api-version set to 2 we can automatically promote the result of HttpClientBuilder.build(NessieApiV1.class) to be a NessieApiV2.

[adutra]

Isn't there a conflict lurking here between setting the api version with a configuration option vs. setting the api version through the parameter passed to HttpClientBuilder.build(Class<NessieApi>)? Imho the proper way to move forward would be to deprecate HttpClientBuilder.build(Class<NessieApi>) and create a new HttpClientBuilder.build() method the honours both the new and old ways.

[dimas-b]

I think having a build(Class<NessieApi>) is still useful for proper type checks on the clients side, especially when the client specifically wants NessieApiV2.

My idea was that version-agnostic clients (like the NessieCatalog in Iceberg) would call build(NessieApiV1.class) since they are compiled to that interface, but use the config property for controlling actual wire format.

Note: API v2 can represent API v1 requests and responses correctly in java.

[ajantha-bhat]

@dimas-b:

I agree that we could add some more checks on the client side using this property.

But can that be handled in a follow-up? Because I didn't get time to explore this and merging this for 0.61.0 release will definitely help in simplifying the Iceberg side PR and getting it merged.

[dimas-b]

But can that be handled in a follow-up? Because I didn't get time to explore this and merging this for 0.61.0 release will definitely help in simplifying the apache/iceberg#6712 and getting it merged.

Having a constant in Nessie code, whose only use case is in Iceberg code, looks odd to me. Iceberg code can already utilize this config setting, so no functionality is affected, as far as I can tell.

[ajantha-bhat]

Having a constant in Nessie code, whose only use case is in Iceberg code, looks odd to me.

we already have something like that. CONF_NESSIE_CLIENT_BUILDER_IMPL.
So, I was just following the style.

nessie/api/client/src/main/java/org/projectnessie/client/NessieConfigConstants.java

Line 245 in e6c29b1

public static final String CONF_NESSIE_CLIENT_BUILDER_IMPL = "nessie.client-builder-impl";

[ajantha-bhat]

Currently no need of this and Iceberg side PR got merged.

In future if, we really need a config level control for controlling write path, we can open up this again.