fix: address review comments on valuation stub replacement

- Return *grpc.ClientConn from buildValuationComponents for proper
  lifecycle management (defer close in caller)
- Remove DefaultConversionMethodId fallback from resolveFromAccountTypes;
  only exact instrument match in valuation method templates is used
- Add pagination documentation to resolveFromAccountTypes

Author: bjcoombs

services/reconciliation/cmd/main.go

@@ -219,7 +219,14 @@ func run(logger *slog.Logger) error {
 	)
 
 	// Wire VarianceValuator with real valuation engine and reference data provider
-	valuationEngine, refDataProvider := buildValuationComponents(cfg, logger)
+	valuationEngine, refDataProvider, refDataConn := buildValuationComponents(cfg, logger)
+	defer func() {
+		if refDataConn != nil {
+			if err := refDataConn.Close(); err != nil {
+				logger.Error("failed to close reference data connection", "error", err)
+			}
+		}
+	}()
 	valuator := service.NewVarianceValuator(valuationEngine, refDataProvider, varianceRepo, runRepo)
 	serviceOpts = append(serviceOpts,
 		service.WithVarianceValuator(valuator.ValueVariances),
@@ -508,7 +515,7 @@ func (h *healthServer) Check(ctx context.Context, _ *grpc_health_v1.HealthCheckR
 // When the Reference Data gRPC URL is configured, it creates gRPC clients for instrument
 // and account type lookups. Otherwise, it falls back to the identity conversion method
 // with default materiality thresholds.
-func buildValuationComponents(cfg *config.Config, logger *slog.Logger) (valuation.Engine, service.ReferenceDataProvider) {
+func buildValuationComponents(cfg *config.Config, logger *slog.Logger) (valuation.Engine, service.ReferenceDataProvider, *grpc.ClientConn) {
 	// Create valuation engine runtime components
 	policyRT, err := valuation.NewPolicyRuntime()
 	if err != nil {
@@ -538,13 +545,16 @@ func buildValuationComponents(cfg *config.Config, logger *slog.Logger) (valuatio
 		Logger:          logger,
 	}
 
+	var refDataConn *grpc.ClientConn
 	if cfg.Services.ReferenceDataURL != "" {
-		refDataConn, connErr := grpc.NewClient(
+		var connErr error
+		refDataConn, connErr = grpc.NewClient(
 			cfg.Services.ReferenceDataURL,
 			grpc.WithTransportCredentials(insecure.NewCredentials()),
 		)
 		if connErr != nil {
 			logger.Warn("failed to create reference data gRPC client", "error", connErr)
+			refDataConn = nil
 		} else {
 			providerCfg.InstrumentClient = referencedatav1.NewReferenceDataServiceClient(refDataConn)
 			providerCfg.AccountTypeClient = referencedatav1.NewAccountTypeRegistryServiceClient(refDataConn)
@@ -563,7 +573,7 @@ func buildValuationComponents(cfg *config.Config, logger *slog.Logger) (valuatio
 		"reference_data_url", cfg.Services.ReferenceDataURL,
 	)
 
-	return adaptedEngine, refDataProvider
+	return adaptedEngine, refDataProvider, refDataConn
 }
 
 // parseLogLevel converts a string log level to slog.Level.

services/reconciliation/service/grpc_reference_data_provider.go

@@ -127,6 +127,8 @@ func (p *GRPCReferenceDataProvider) GetMaterialityThreshold(ctx context.Context,
 
 // resolveFromAccountTypes searches active account type definitions for a valuation
 // method template matching the given instrument code.
+// Note: queries up to 100 active account types. Deployments with more than 100
+// active account types should extend this with pagination.
 func (p *GRPCReferenceDataProvider) resolveFromAccountTypes(ctx context.Context, instrumentCode string) (uuid.UUID, error) {
 	resp, err := p.accountTypeClient.ListActive(ctx, &referencedatav1.ListActiveRequest{
 		PageSize: 100,
@@ -135,6 +137,7 @@ func (p *GRPCReferenceDataProvider) resolveFromAccountTypes(ctx context.Context,
 		return uuid.Nil, fmt.Errorf("failed to list active account types: %w", err)
 	}
 
+	// First pass: look for an exact instrument match in valuation method templates
 	for _, def := range resp.GetDefinitions() {
 		for _, vm := range def.GetValuationMethods() {
 			if vm.GetInputInstrument() == instrumentCode {
@@ -145,14 +148,6 @@ func (p *GRPCReferenceDataProvider) resolveFromAccountTypes(ctx context.Context,
 				return methodID, nil
 			}
 		}
-
-		// Check default conversion method as fallback
-		if convID := def.GetDefaultConversionMethodId(); convID != "" {
-			methodID, err := uuid.Parse(convID)
-			if err == nil {
-				return methodID, nil
-			}
-		}
 	}
 
 	return uuid.Nil, nil

services/reconciliation/service/grpc_reference_data_provider_test.go

@@ -183,24 +183,25 @@ func TestGRPCReferenceDataProvider_GetValuationMethodID_AccountTypeError_FallsBa
 	assert.Equal(t, defaultID, result)
 }
 
-func TestGRPCReferenceDataProvider_GetValuationMethodID_DefaultConversionFallback(t *testing.T) {
-	conversionID := uuid.New()
+func TestGRPCReferenceDataProvider_GetValuationMethodID_NoMatchFallsToDefault(t *testing.T) {
+	defaultID := uuid.New()
 	acctClient := &mockAccountTypeClient{
 		definitions: []*referencedatav1.AccountTypeDefinition{
 			{
 				Code:                      "CUSTOMER_CURRENT",
-				DefaultConversionMethodId: conversionID.String(),
+				DefaultConversionMethodId: uuid.New().String(),
 				// No ValuationMethods matching "EXOTIC" instrument
 			},
 		},
 	}
 
 	provider := NewGRPCReferenceDataProvider(GRPCReferenceDataProviderConfig{
 		AccountTypeClient: acctClient,
+		DefaultMethodID:   defaultID,
 		Logger:            testLogger(),
 	})
 
 	result, err := provider.GetValuationMethodID(context.Background(), "EXOTIC")
 	require.NoError(t, err)
-	assert.Equal(t, conversionID, result)
+	assert.Equal(t, defaultID, result, "should fall back to default when no instrument match")
 }