Backend for configuring a self-hosted model per Duo tool / sub-feature

Overview

In Configuration of Declared Models to Duo Feature... (#469612 - closed) we consider configuring a self-hosted model per Duo Chat tool. We need to prepare the backend to send specific self-hosted model metadata for a specific tool or Duo sub-feature.

(note: tool is the terminology specifically used for Duo Chat sub-features, but work on this issue will support both Duo Chat sub-features (aka tools) and other Duo sub-features (such as Code Generation and Code Completion for Code Suggestions)

Proposal

1. List of tools: #469612 (comment 2002997874)
2. Extend the list of features in AiFeature to contain tools:

    enum feature: {
      code_generations: 0,
      code_completions: 1,
      duo_chat: 2,
      duo_chat_issue_reader: 3,
      ...
      duo_chat_explain_code: n,
      ...
    }

The enum in AiFeature is flat while Configuration of Declared Models to Duo Feature... (#469612 - closed) investigates grouping features into sections: for example, Code Suggestions is a section or a Feature while Code Completion and Code Generation are its sub-features.

2. Then we could use the setting to fetch self-hosted model info:

def chat_feature_setting(unit_primitive: nil)
  feature_name = unit_primitive ? "duo_chat_#{unit_primitive}" : :duo_chat
  ::Ai::FeatureSetting.find_by_feature(:duo_chat)
end

3. In order to do that, we need to distinguish between tools and unit_primitive variable would be useful. However, it's not propagated properly and is nil at the moment and if it would, a bit different endpoint would be used. Propagating the unit primitive is a blocker to implementing this issue but can be done within this issue. It can be either aligned with groupai framework and groupduo chat (comment) or we could add a condition: if the feature is not self-hosted - nullify the unit-primitive, i.e use the value only for self-hosted features.

Note

If it's implemented alone, the UI/UX will be the following until it's reworked Configuration of Declared Models to Duo Feature... (#469612 - closed)