Fix deleting function that is used as authorizer (#474)

Author: mthenw

function/errors.go

@@ -31,6 +31,16 @@ func (e ErrFunctionValidation) Error() string {
 	return fmt.Sprintf("Function doesn't validate. Validation error: %s", e.Message)
 }
 
+// ErrFunctionIsAuthorizer occurs when function cannot be deleted because is used as authorizer.
+type ErrFunctionIsAuthorizer struct {
+	ID        ID
+	EventType string
+}
+
+func (e ErrFunctionIsAuthorizer) Error() string {
+	return fmt.Sprintf("Function %s cannot be deleted because is used as an authorizer for %s event type.", e.ID, e.EventType)
+}
+
 // ErrFunctionCallFailed occurs when function call failed.
 type ErrFunctionCallFailed struct {
 	Original error

httpapi/httpapi.go

@@ -328,6 +328,8 @@ func (h HTTPAPI) deleteFunction(w http.ResponseWriter, r *http.Request, params h
 			w.WriteHeader(http.StatusNotFound)
 		} else if _, ok := err.(*function.ErrFunctionHasSubscriptions); ok {
 			w.WriteHeader(http.StatusBadRequest)
+		} else if _, ok := err.(*function.ErrFunctionIsAuthorizer); ok {
+			w.WriteHeader(http.StatusBadRequest)
 		} else {
 			w.WriteHeader(http.StatusInternalServerError)
 		}

httpapi/httpapi_test.go

@@ -480,6 +480,17 @@ func TestDeleteFunction(t *testing.T) {
 		assert.Equal(t, "Function cannot be deleted because it's subscribed to a least one event.", httpresp.Errors[0].Message)
 	})
 
+	t.Run("function is authorizer", func(t *testing.T) {
+		functions.EXPECT().DeleteFunction(gomock.Any(), gomock.Any()).Return(&function.ErrFunctionIsAuthorizer{ID: function.ID("func1"), EventType: "test.event"})
+
+		resp := request(router, http.MethodDelete, "/v1/spaces/default/functions/func1", nil)
+
+		httpresp := &httpapi.Response{}
+		json.Unmarshal(resp.Body.Bytes(), httpresp)
+		assert.Equal(t, http.StatusBadRequest, resp.Code)
+		assert.Equal(t, "Function func1 cannot be deleted because is used as an authorizer for test.event event type.", httpresp.Errors[0].Message)
+	})
+
 	t.Run("function not found", func(t *testing.T) {
 		functions.EXPECT().DeleteFunction(gomock.Any(), gomock.Any()).Return(&function.ErrFunctionNotFound{ID: function.ID("testid")})
 

libkv/function.go

@@ -133,6 +133,16 @@ func (service Service) DeleteFunction(space string, id function.ID) error {
 		}
 	}
 
+	eventTypes, err := service.ListEventTypes(space)
+	if err != nil {
+		return err
+	}
+	for _, eventType := range eventTypes {
+		if id == *eventType.AuthorizerID {
+			return &function.ErrFunctionIsAuthorizer{ID: id, EventType: string(eventType.Name)}
+		}
+	}
+
 	err = service.FunctionStore.Delete(FunctionKey{space, id}.String())
 	if err != nil {
 		return &function.ErrFunctionNotFound{ID: id}

libkv/function_test.go

@@ -223,9 +223,11 @@ func TestDeleteFunction(t *testing.T) {
 		kvs := []*store.KVPair{}
 		subscriptionsDB := mock.NewMockStore(ctrl)
 		subscriptionsDB.EXPECT().List("default/", &store.ReadOptions{Consistent: true}).Return(kvs, nil)
+		eventTypesDB := mock.NewMockStore(ctrl)
+		eventTypesDB.EXPECT().List("default/", &store.ReadOptions{Consistent: true}).Return(kvs, nil)
 		functionsDB := mock.NewMockStore(ctrl)
 		functionsDB.EXPECT().Delete("default/testid").Return(nil)
-		service := &Service{FunctionStore: functionsDB, SubscriptionStore: subscriptionsDB, Log: zap.NewNop()}
+		service := &Service{FunctionStore: functionsDB, SubscriptionStore: subscriptionsDB, EventTypeStore: eventTypesDB, Log: zap.NewNop()}
 
 		err := service.DeleteFunction("default", function.ID("testid"))
 
@@ -236,9 +238,11 @@ func TestDeleteFunction(t *testing.T) {
 		kvs := []*store.KVPair{}
 		subscriptionsDB := mock.NewMockStore(ctrl)
 		subscriptionsDB.EXPECT().List("default/", &store.ReadOptions{Consistent: true}).Return(kvs, nil)
+		eventTypesDB := mock.NewMockStore(ctrl)
+		eventTypesDB.EXPECT().List("default/", &store.ReadOptions{Consistent: true}).Return(kvs, nil)
 		functionsDB := mock.NewMockStore(ctrl)
 		functionsDB.EXPECT().Delete("default/testid").Return(errors.New("KV func not found"))
-		service := &Service{FunctionStore: functionsDB, SubscriptionStore: subscriptionsDB, Log: zap.NewNop()}
+		service := &Service{FunctionStore: functionsDB, SubscriptionStore: subscriptionsDB, EventTypeStore: eventTypesDB, Log: zap.NewNop()}
 
 		err := service.DeleteFunction("default", function.ID("testid"))
 
@@ -257,6 +261,21 @@ func TestDeleteFunction(t *testing.T) {
 
 		assert.Equal(t, err, &function.ErrFunctionHasSubscriptions{})
 	})
+
+	t.Run("function is authorizer", func(t *testing.T) {
+		kvs := []*store.KVPair{
+			{Value: []byte(`{"name":"test.event","authorizerId":"testid"}`)}}
+		eventTypesDB := mock.NewMockStore(ctrl)
+		eventTypesDB.EXPECT().List("default/", &store.ReadOptions{Consistent: true}).Return(kvs, nil)
+		subscriptionsDB := mock.NewMockStore(ctrl)
+		subscriptionsDB.EXPECT().List("default/", &store.ReadOptions{Consistent: true}).Return([]*store.KVPair{}, nil)
+		functionsDB := mock.NewMockStore(ctrl)
+		service := &Service{FunctionStore: functionsDB, SubscriptionStore: subscriptionsDB, EventTypeStore: eventTypesDB, Log: zap.NewNop()}
+
+		err := service.DeleteFunction("default", function.ID("testid"))
+
+		assert.Equal(t, err, &function.ErrFunctionIsAuthorizer{ID: function.ID("testid"), EventType: "test.event"})
+	})
 }
 
 func TestValidateFunction(t *testing.T) {