Forbid exporting the built-in dstack Sky gateway

src/dstack/_internal/server/services/exports.py

@@ -11,6 +11,7 @@
     ResourceNotExistsError,
     ServerClientError,
 )
+from dstack._internal.core.models.backends.base import BackendType
 from dstack._internal.core.models.exports import (
     Export,
     ExportedFleet,
@@ -299,8 +300,12 @@ async def add_exported_gateways(
         raise ServerClientError(
             f"Gateways {already_exported} are already exported by export {export.name!r}"
         )
-    gateways = await list_project_gateway_models(session=session, project=export.project)
+    gateways = await list_project_gateway_models(
+        session=session, project=export.project, load_backend_type=True
+    )
     gateways = [g for g in gateways if g.name in names]
+    if any(g.backend.type == BackendType.DSTACK for g in gateways):
+        raise ServerClientError("Exporting the built-in dstack Sky gateway is not allowed")
     if missing := set(names) - {g.name for g in gateways}:
         raise ResourceNotExistsError(
             f"Gateways {missing} not found in project {export.project.name!r}"

src/tests/_internal/server/routers/test_exports.py

@@ -5,6 +5,7 @@
 from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from dstack._internal.core.models.backends.base import BackendType
 from dstack._internal.core.models.users import GlobalRole, ProjectRole
 from dstack._internal.server.models import ExportModel
 from dstack._internal.server.services.projects import add_project_member
@@ -210,6 +211,14 @@ async def test_creates_empty_export(self, session: AsyncSession, client: AsyncCl
                 "Fleets ['cloud-fleet'] are cloud fleets. Can only export SSH fleets",
                 id="cloud-fleet",
             ),
+            pytest.param(
+                {
+                    "name": "test-export",
+                    "exported_gateways": ["sky-gateway"],
+                },
+                "Exporting the built-in dstack Sky gateway is not allowed",
+                id="sky-gateway",
+            ),
             pytest.param(
                 {
                     "name": "test-export",
@@ -269,6 +278,15 @@ async def test_rejects_invalid_export(
             backend_id=backend.id,
             name="exported-gateway",
         )
+        sky_backend = await create_backend(
+            session=session, project_id=project.id, backend_type=BackendType.DSTACK
+        )
+        await create_gateway(
+            session=session,
+            project_id=project.id,
+            backend_id=sky_backend.id,
+            name="sky-gateway",
+        )
         not_permitted_project = await create_project(
             session=session, name="NotPermittedProject", owner=user
         )
@@ -650,6 +668,14 @@ async def test_can_add_same_entities_as_existing_deleted_ones(
                 "Fleets ['cloud-fleet'] are cloud fleets. Can only export SSH fleets",
                 id="add-cloud-fleet",
             ),
+            pytest.param(
+                {
+                    "name": "test-export",
+                    "add_exported_gateways": ["sky-gateway"],
+                },
+                "Exporting the built-in dstack Sky gateway is not allowed",
+                id="add-sky-gateway",
+            ),
             pytest.param(
                 {
                     "name": "test-export",
@@ -810,6 +836,15 @@ async def test_rejects_invalid_update(
             name="not-exported-fleet",
             spec=get_fleet_spec(get_ssh_fleet_configuration()),
         )
+        sky_backend = await create_backend(
+            session=session, project_id=project.id, backend_type=BackendType.DSTACK
+        )
+        await create_gateway(
+            session=session,
+            project_id=project.id,
+            backend_id=sky_backend.id,
+            name="sky-gateway",
+        )
         not_importer_project = await create_project(
             session=session, name="NotImporterProject", owner=user
         )