Refactor backends module to avoid importing deps on models import

src/dstack/_internal/core/backends/__init__.py

@@ -1,65 +0,0 @@
-from dstack._internal.core.backends.base.compute import (
-    ComputeWithCreateInstanceSupport,
-    ComputeWithGatewaySupport,
-    ComputeWithMultinodeSupport,
-    ComputeWithPlacementGroupSupport,
-    ComputeWithPrivateGatewaySupport,
-    ComputeWithReservationSupport,
-    ComputeWithVolumeSupport,
-)
-from dstack._internal.core.backends.base.configurator import Configurator
-from dstack._internal.core.backends.configurators import list_available_configurator_classes
-from dstack._internal.core.backends.local.compute import LocalCompute
-from dstack._internal.core.models.backends.base import BackendType
-from dstack._internal.settings import LOCAL_BACKEND_ENABLED
-
-
-def _get_backends_with_compute_feature(
-    configurator_classes: list[type[Configurator]],
-    compute_feature_class: type,
-) -> list[BackendType]:
-    backend_types_and_computes = [
-        (configurator_class.TYPE, configurator_class.BACKEND_CLASS.COMPUTE_CLASS)
-        for configurator_class in configurator_classes
-    ]
-    if LOCAL_BACKEND_ENABLED:
-        backend_types_and_computes.append((BackendType.LOCAL, LocalCompute))
-    backend_types = []
-    for backend_type, compute_class in backend_types_and_computes:
-        if issubclass(compute_class, compute_feature_class):
-            backend_types.append(backend_type)
-    return backend_types
-
-
-_configurator_classes = list_available_configurator_classes()
-
-
-# The following backend lists do not include unavailable backends (i.e. backends missing deps).
-BACKENDS_WITH_CREATE_INSTANCE_SUPPORT = _get_backends_with_compute_feature(
-    configurator_classes=_configurator_classes,
-    compute_feature_class=ComputeWithCreateInstanceSupport,
-)
-BACKENDS_WITH_MULTINODE_SUPPORT = [BackendType.REMOTE] + _get_backends_with_compute_feature(
-    configurator_classes=_configurator_classes,
-    compute_feature_class=ComputeWithMultinodeSupport,
-)
-BACKENDS_WITH_PLACEMENT_GROUPS_SUPPORT = _get_backends_with_compute_feature(
-    configurator_classes=_configurator_classes,
-    compute_feature_class=ComputeWithPlacementGroupSupport,
-)
-BACKENDS_WITH_RESERVATION_SUPPORT = _get_backends_with_compute_feature(
-    configurator_classes=_configurator_classes,
-    compute_feature_class=ComputeWithReservationSupport,
-)
-BACKENDS_WITH_GATEWAY_SUPPORT = _get_backends_with_compute_feature(
-    configurator_classes=_configurator_classes,
-    compute_feature_class=ComputeWithGatewaySupport,
-)
-BACKENDS_WITH_PRIVATE_GATEWAY_SUPPORT = _get_backends_with_compute_feature(
-    configurator_classes=_configurator_classes,
-    compute_feature_class=ComputeWithPrivateGatewaySupport,
-)
-BACKENDS_WITH_VOLUMES_SUPPORT = _get_backends_with_compute_feature(
-    configurator_classes=_configurator_classes,
-    compute_feature_class=ComputeWithVolumeSupport,
-)

src/dstack/_internal/core/backends/features.py

@@ -0,0 +1,64 @@
+from dstack._internal.core.backends.base.compute import (
+    ComputeWithCreateInstanceSupport,
+    ComputeWithGatewaySupport,
+    ComputeWithMultinodeSupport,
+    ComputeWithPlacementGroupSupport,
+    ComputeWithPrivateGatewaySupport,
+    ComputeWithReservationSupport,
+    ComputeWithVolumeSupport,
+)
+from dstack._internal.core.backends.base.configurator import Configurator
+from dstack._internal.core.backends.configurators import list_available_configurator_classes
+from dstack._internal.core.backends.local.compute import LocalCompute
+from dstack._internal.core.models.backends.base import BackendType
+from dstack._internal.settings import LOCAL_BACKEND_ENABLED
+
+_configurator_classes = list_available_configurator_classes()
+
+
+def _get_backends_with_compute_feature(
+    configurator_classes: list[type[Configurator]],
+    compute_feature_class: type,
+) -> list[BackendType]:
+    backend_types_and_computes = [
+        (configurator_class.TYPE, configurator_class.BACKEND_CLASS.COMPUTE_CLASS)
+        for configurator_class in configurator_classes
+    ]
+    if LOCAL_BACKEND_ENABLED:
+        backend_types_and_computes.append((BackendType.LOCAL, LocalCompute))
+    backend_types = []
+    for backend_type, compute_class in backend_types_and_computes:
+        if issubclass(compute_class, compute_feature_class):
+            backend_types.append(backend_type)
+    return backend_types
+
+
+# The following backend lists do not include unavailable backends (i.e. backends missing deps).
+BACKENDS_WITH_CREATE_INSTANCE_SUPPORT = _get_backends_with_compute_feature(
+    configurator_classes=_configurator_classes,
+    compute_feature_class=ComputeWithCreateInstanceSupport,
+)
+BACKENDS_WITH_MULTINODE_SUPPORT = [BackendType.REMOTE] + _get_backends_with_compute_feature(
+    configurator_classes=_configurator_classes,
+    compute_feature_class=ComputeWithMultinodeSupport,
+)
+BACKENDS_WITH_PLACEMENT_GROUPS_SUPPORT = _get_backends_with_compute_feature(
+    configurator_classes=_configurator_classes,
+    compute_feature_class=ComputeWithPlacementGroupSupport,
+)
+BACKENDS_WITH_RESERVATION_SUPPORT = _get_backends_with_compute_feature(
+    configurator_classes=_configurator_classes,
+    compute_feature_class=ComputeWithReservationSupport,
+)
+BACKENDS_WITH_GATEWAY_SUPPORT = _get_backends_with_compute_feature(
+    configurator_classes=_configurator_classes,
+    compute_feature_class=ComputeWithGatewaySupport,
+)
+BACKENDS_WITH_PRIVATE_GATEWAY_SUPPORT = _get_backends_with_compute_feature(
+    configurator_classes=_configurator_classes,
+    compute_feature_class=ComputeWithPrivateGatewaySupport,
+)
+BACKENDS_WITH_VOLUMES_SUPPORT = _get_backends_with_compute_feature(
+    configurator_classes=_configurator_classes,
+    compute_feature_class=ComputeWithVolumeSupport,
+)

src/dstack/_internal/server/background/tasks/process_instances.py

@@ -12,10 +12,6 @@
 from sqlalchemy.orm import joinedload, lazyload
 
 from dstack._internal import settings
-from dstack._internal.core.backends import (
-    BACKENDS_WITH_CREATE_INSTANCE_SUPPORT,
-    BACKENDS_WITH_PLACEMENT_GROUPS_SUPPORT,
-)
 from dstack._internal.core.backends.base.compute import (
     ComputeWithCreateInstanceSupport,
     ComputeWithPlacementGroupSupport,
@@ -27,6 +23,10 @@
     get_shim_env,
     get_shim_pre_start_commands,
 )
+from dstack._internal.core.backends.features import (
+    BACKENDS_WITH_CREATE_INSTANCE_SUPPORT,
+    BACKENDS_WITH_PLACEMENT_GROUPS_SUPPORT,
+)
 from dstack._internal.core.backends.remote.provisioning import (
     detect_cpu_arch,
     get_host_info,

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

@@ -8,8 +8,8 @@
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import joinedload, selectinload
 
-from dstack._internal.core.backends import BACKENDS_WITH_CREATE_INSTANCE_SUPPORT
 from dstack._internal.core.backends.base.backend import Backend
+from dstack._internal.core.backends.features import BACKENDS_WITH_CREATE_INSTANCE_SUPPORT
 from dstack._internal.core.errors import (
     ForbiddenError,
     ResourceExistsError,

src/dstack/_internal/server/services/gateways/__init__.py

@@ -11,16 +11,16 @@
 from sqlalchemy.orm import selectinload
 
 import dstack._internal.utils.random_names as random_names
-from dstack._internal.core.backends import (
-    BACKENDS_WITH_GATEWAY_SUPPORT,
-    BACKENDS_WITH_PRIVATE_GATEWAY_SUPPORT,
-)
 from dstack._internal.core.backends.base.compute import (
     Compute,
     ComputeWithGatewaySupport,
     get_dstack_gateway_wheel,
     get_dstack_runner_version,
 )
+from dstack._internal.core.backends.features import (
+    BACKENDS_WITH_GATEWAY_SUPPORT,
+    BACKENDS_WITH_PRIVATE_GATEWAY_SUPPORT,
+)
 from dstack._internal.core.errors import (
     GatewayError,
     ResourceNotExistsError,

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

@@ -8,11 +8,11 @@
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import joinedload
 
-from dstack._internal.core.backends import BACKENDS_WITH_MULTINODE_SUPPORT
 from dstack._internal.core.backends.base.offers import (
     offer_to_catalog_item,
     requirements_to_query_filter,
 )
+from dstack._internal.core.backends.features import BACKENDS_WITH_MULTINODE_SUPPORT
 from dstack._internal.core.models.backends.base import BackendType
 from dstack._internal.core.models.envs import Env
 from dstack._internal.core.models.instances import (

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

@@ -2,13 +2,13 @@
 
 import gpuhunt
 
-from dstack._internal.core.backends import (
+from dstack._internal.core.backends.base.backend import Backend
+from dstack._internal.core.backends.base.compute import ComputeWithPlacementGroupSupport
+from dstack._internal.core.backends.features import (
     BACKENDS_WITH_CREATE_INSTANCE_SUPPORT,
     BACKENDS_WITH_MULTINODE_SUPPORT,
     BACKENDS_WITH_RESERVATION_SUPPORT,
 )
-from dstack._internal.core.backends.base.backend import Backend
-from dstack._internal.core.backends.base.compute import ComputeWithPlacementGroupSupport
 from dstack._internal.core.models.backends.base import BackendType
 from dstack._internal.core.models.instances import (
     InstanceOfferWithAvailability,

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

@@ -6,8 +6,8 @@
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import joinedload, selectinload
 
-from dstack._internal.core.backends import BACKENDS_WITH_VOLUMES_SUPPORT
 from dstack._internal.core.backends.base.compute import ComputeWithVolumeSupport
+from dstack._internal.core.backends.features import BACKENDS_WITH_VOLUMES_SUPPORT
 from dstack._internal.core.errors import (
     BackendNotAvailable,
     ResourceExistsError,