Function buildRerankingConfig

pkg/rag/builder.go:144–222

buildRerankingConfig constructs a RerankingConfig from the configuration.

(
	ctx context.Context,
	rerankCfg *latest.RAGRerankingConfig,
	buildCfg ManagersBuildConfig,
	globalLimit int,
)

// buildRerankingConfig constructs a RerankingConfig from the configuration.
func buildRerankingConfig(
	ctx context.Context,
	rerankCfg *latest.RAGRerankingConfig,
	buildCfg ManagersBuildConfig,
	globalLimit int,
) (*RerankingConfig, error) {
	if rerankCfg == nil {
		return nil, nil
	}

	if rerankCfg.Model == "" {
		slog.ErrorContext(ctx, "Reranking model name is empty")
		return nil, errors.New("reranking model is required")
	}

	slog.DebugContext(ctx, "Resolving reranking model",
		"model_ref", rerankCfg.Model)

	// Resolve model config - check if it's a reference to a defined model or inline
	modelCfgVal, err := strategy.ResolveModelConfig(rerankCfg.Model, buildCfg.Models)
	if err != nil {
		slog.ErrorContext(ctx, "Failed to resolve reranking model",
			"model_ref", rerankCfg.Model,
			"error", err)
		return nil, fmt.Errorf("failed to resolve reranking model %q: %w", rerankCfg.Model, err)
	}
	modelCfg := &modelCfgVal

	slog.DebugContext(ctx, "Resolved reranking model config",
		"provider", modelCfg.Provider,
		"model", modelCfg.Model)

	// Create provider for reranking model
	rerankProvider, err := buildCfg.NewProvider(ctx, modelCfg)
	if err != nil {
		slog.ErrorContext(ctx, "Failed to create reranking provider",
			"provider", modelCfg.Provider,
			"model", modelCfg.Model,
			"error", err)
		return nil, fmt.Errorf("failed to create reranking provider: %w", err)
	}

	slog.DebugContext(ctx, "Created reranking provider",
		"provider_id", rerankProvider.ID())

	// Determine effective TopK:
	// - If user provided a positive top_k, respect it.
	// - Otherwise, default to the global results limit when set.
	//   This avoids reranking unbounded result sets while still
	//   using a sensible, user-controlled cap.
	effectiveTopK := rerankCfg.TopK
	if effectiveTopK <= 0 && globalLimit > 0 {
		effectiveTopK = globalLimit
	}

	// Create reranker
	reranker, err := rerank.NewLLMReranker(rerank.Config{
		Model:     rerankProvider,