feat(customcurrencies): gate API with credits flag

Author: turip

.agents/skills/charges/SKILL.md

@@ -643,7 +643,6 @@ Use these conventions for lifecycle tests:
 - for credit-only charges (usage-based or flat fee), handler callbacks must not return credit allocations above the requested amount; exact allocation paths must return allocations that sum to the requested amount
 - for flat fee credit-only tests, use `mustAdvanceFlatFeeCharges(...)` helper — it filters the advance result to flat fee charges only
 - for credit-purchase state-machine unit tests, use testify `mock.Mock` with `On(...).Run(...).Return(...).Once()` for expected handler callbacks so missing or unexpected calls fail; in service-suite tests, leave callbacks unset when validating that a flow fails before callbacks, because the shared `CreditPurchaseTestHandler` already errors if an unset callback is invoked
-- keep custom-currency support disabled on default charge service instances so tests continue covering the production unsupported boundary; when a test needs it enabled, use a semantic suite helper that constructs and enables the service instead of repeating `SetEnableCustomCurrency` interface assertions at call sites
 - when testing timestamp truncation, use sub-second fixtures and assert the persisted charge/run fields are second-aligned after create/advance
 - `time.Time` fields on domain models are value typed; use `s.False(ts.IsZero())` instead of `s.NotNil(ts)` when asserting they are populated
 - cover the temporary shrink/extend remap path as well; it synthesizes new intents and must normalize the replacement period ends before re-create

api/v3/handlers/currencies/create.go

@@ -13,6 +13,7 @@ import (
 	"github.com/openmeterio/openmeter/pkg/currencyx"
 	"github.com/openmeterio/openmeter/pkg/framework/commonhttp"
 	"github.com/openmeterio/openmeter/pkg/framework/transport/httptransport"
+	"github.com/openmeterio/openmeter/pkg/models"
 )
 
 type (
@@ -24,6 +25,10 @@ type (
 func (h *handler) CreateCurrency() CreateCurrencyHandler {
 	return httptransport.NewHandler(
 		func(ctx context.Context, r *http.Request) (CreateCurrencyRequest, error) {
+			if !h.creditsEnabled {
+				return CreateCurrencyRequest{}, models.NewGenericValidationError(errCustomCurrenciesDisabled)
+			}
+
 			ns, err := h.resolveNamespace(ctx)
 			if err != nil {
 				return CreateCurrencyRequest{}, fmt.Errorf("failed to resolve namespace: %w", err)

api/v3/handlers/currencies/create_cost_basis.go

@@ -13,6 +13,7 @@ import (
 	"github.com/openmeterio/openmeter/pkg/currencyx"
 	"github.com/openmeterio/openmeter/pkg/framework/commonhttp"
 	"github.com/openmeterio/openmeter/pkg/framework/transport/httptransport"
+	"github.com/openmeterio/openmeter/pkg/models"
 )
 
 type (
@@ -24,6 +25,10 @@ type (
 func (h *handler) CreateCostBasis() CreateCostBasisHandler {
 	return httptransport.NewHandlerWithArgs(
 		func(ctx context.Context, r *http.Request, currencyID string) (CreateCostBasisRequest, error) {
+			if !h.creditsEnabled {
+				return CreateCostBasisRequest{}, models.NewGenericValidationError(errCustomCurrenciesDisabled)
+			}
+
 			ns, err := h.resolveNamespace(ctx)
 			if err != nil {
 				return CreateCostBasisRequest{}, err

api/v3/handlers/currencies/handler.go

@@ -2,11 +2,14 @@ package currencies
 
 import (
 	"context"
+	"errors"
 
 	"github.com/openmeterio/openmeter/openmeter/currencies"
 	"github.com/openmeterio/openmeter/pkg/framework/transport/httptransport"
 )
 
+var errCustomCurrenciesDisabled = errors.New("custom currencies are not enabled on this deployment of OpenMeter")
+
 type Handler interface {
 	ListCurrencies() ListCurrenciesHandler
 	CreateCurrency() CreateCurrencyHandler
@@ -19,16 +22,19 @@ type handler struct {
 	resolveNamespace func(ctx context.Context) (string, error)
 	options          []httptransport.HandlerOption
 	service          currencies.Service
+	creditsEnabled   bool
 }
 
 func New(
 	resolveNamespace func(ctx context.Context) (string, error),
 	currencyService currencies.Service,
+	creditsEnabled bool,
 	options ...httptransport.HandlerOption,
 ) Handler {
 	return &handler{
 		resolveNamespace: resolveNamespace,
 		options:          options,
 		service:          currencyService,
+		creditsEnabled:   creditsEnabled,
 	}
 }

api/v3/handlers/currencies/handler_test.go

@@ -0,0 +1,34 @@
+package currencies
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCustomCurrencyMutationsRequireCredits(t *testing.T) {
+	handler := New(func(context.Context) (string, error) {
+		return "test", nil
+	}, nil, false)
+
+	t.Run("create currency", func(t *testing.T) {
+		request := httptest.NewRequest(http.MethodPost, "/api/v3/openmeter/currencies/custom", nil)
+		response := httptest.NewRecorder()
+
+		handler.CreateCurrency().ServeHTTP(response, request)
+
+		require.Equal(t, http.StatusBadRequest, response.Code)
+	})
+
+	t.Run("create cost basis", func(t *testing.T) {
+		request := httptest.NewRequest(http.MethodPost, "/api/v3/openmeter/currencies/custom/currency-id/cost-bases", nil)
+		response := httptest.NewRecorder()
+
+		handler.CreateCostBasis().With("currency-id").ServeHTTP(response, request)
+
+		require.Equal(t, http.StatusBadRequest, response.Code)
+	})
+}

api/v3/handlers/currencies/list_test.go

@@ -53,7 +53,7 @@ func TestListCurrenciesFilterByType(t *testing.T) {
 			service := &listCurrenciesService{}
 			handler := New(func(context.Context) (string, error) {
 				return "test", nil
-			}, service)
+			}, service, true)
 
 			request := httptest.NewRequest(http.MethodGet, "/api/v3/currencies", nil)
 			response := httptest.NewRecorder()

api/v3/server/server.go

@@ -332,7 +332,7 @@ func NewServer(config *Config) (*Server, error) {
 	plansHandler := planshandler.New(resolveNamespace, config.PlanService, config.UnitConfig.Enabled, httptransport.WithErrorHandler(config.ErrorHandler))
 	planAddonsHandler := planaddonshandler.New(resolveNamespace, config.PlanService, config.PlanAddonService, httptransport.WithErrorHandler(config.ErrorHandler))
 	taxcodesHandler := taxcodeshandler.New(resolveNamespace, config.TaxCodeService, httptransport.WithErrorHandler(config.ErrorHandler))
-	currenciesHandler := currencieshandler.New(resolveNamespace, config.CurrencyService, httptransport.WithErrorHandler(config.ErrorHandler))
+	currenciesHandler := currencieshandler.New(resolveNamespace, config.CurrencyService, config.Credits.Enabled, httptransport.WithErrorHandler(config.ErrorHandler))
 
 	var chargesH chargeshandler.Handler
 	if config.ChargeService != nil {

openmeter/billing/charges/creditpurchase/service/create.go

@@ -8,7 +8,6 @@ import (
 
 	"github.com/openmeterio/openmeter/openmeter/billing"
 	"github.com/openmeterio/openmeter/openmeter/billing/charges/creditpurchase"
-	"github.com/openmeterio/openmeter/openmeter/billing/charges/meta"
 	"github.com/openmeterio/openmeter/openmeter/productcatalog"
 	"github.com/openmeterio/openmeter/pkg/framework/transaction"
 	"github.com/openmeterio/openmeter/pkg/models"
@@ -20,10 +19,6 @@ func (s *service) Create(ctx context.Context, input creditpurchase.CreateInput)
 	}
 
 	return transaction.Run(ctx, s.adapter, func(ctx context.Context) (creditpurchase.ChargeWithGatheringLine, error) {
-		if input.Intent.Currency.IsCustom() && !s.enableCustomCurrency.Load() {
-			return creditpurchase.ChargeWithGatheringLine{}, fmt.Errorf("custom currency %s is not supported for credit purchases: %w", input.Intent.Currency.GetCode(), meta.ErrCustomCurrencyNotSupported)
-		}
-
 		input.Intent = input.Intent.Normalized()
 
 		// Let's create the credit purchase charge

openmeter/billing/charges/creditpurchase/service/service.go

@@ -3,8 +3,6 @@ package service
 import (
 	"errors"
 	"fmt"
-	"sync/atomic"
-	"testing"
 
 	"github.com/openmeterio/openmeter/openmeter/billing/charges/creditpurchase"
 	creditpurchaserealizations "github.com/openmeterio/openmeter/openmeter/billing/charges/creditpurchase/service/realizations"
@@ -65,20 +63,9 @@ func New(config Config) (creditpurchase.Service, error) {
 }
 
 type service struct {
-	adapter              creditpurchase.Adapter
-	metaAdapter          meta.Adapter
-	handler              creditpurchase.Handler
-	lineage              lineage.Service
-	realizations         *creditpurchaserealizations.Service
-	enableCustomCurrency atomic.Bool
-}
-
-func (s *service) SetEnableCustomCurrency(t *testing.T, enabled bool) error {
-	if t == nil {
-		return errors.New("testing is nil")
-	}
-
-	t.Helper()
-	s.enableCustomCurrency.Store(enabled)
-	return nil
+	adapter      creditpurchase.Adapter
+	metaAdapter  meta.Adapter
+	handler      creditpurchase.Handler
+	lineage      lineage.Service
+	realizations *creditpurchaserealizations.Service
 }

openmeter/billing/charges/flatfee/service/create.go

@@ -33,10 +33,6 @@ func (s *service) Create(ctx context.Context, input flatfee.CreateInput) ([]flat
 		now := clock.Now().UTC()
 		// Let's create all the flat fee charges in bulk
 		intentsWithStatus, err := slicesx.MapWithErr(input.Intents, func(intent flatfee.Intent) (flatfee.IntentWithInitialStatus, error) {
-			if intent.Currency.IsCustom() && !s.enableCustomCurrency.Load() {
-				return flatfee.IntentWithInitialStatus{}, fmt.Errorf("creating flat fee charge with custom currency %q: %w", intent.Currency.GetCode(), meta.ErrCustomCurrencyNotSupported)
-			}
-
 			chargeIntent := intent.Normalized()
 
 			var resolvedCostBasis *costbasis.State