[Core] Object spilling prototype (#9818)

python/ray/experimental/__init__.py

@@ -1,10 +1,13 @@
 from .api import get, wait
 from .dynamic_resources import set_resource
+from .object_spilling import force_spill_objects, force_restore_spilled_objects
 from .placement_group import (
     placement_group, )
 __all__ = [
     "get",
     "wait",
     "set_resource",
+    "force_spill_objects",
+    "force_restore_spilled_objects",
     "placement_group",
 ]

python/ray/experimental/object_spilling.py

@@ -0,0 +1,35 @@
+import ray
+
+
+def force_spill_objects(object_refs):
+    """Force spilling objects to external storage.
+
+    Args:
+        object_refs: Object refs of the objects to be
+            spilled.
+    """
+    core_worker = ray.worker.global_worker.core_worker
+    # Make sure that the values are object refs.
+    for object_ref in object_refs:
+        if not isinstance(object_ref, ray.ObjectRef):
+            raise TypeError(
+                f"Attempting to call `force_spill_objects` on the "
+                f"value {object_ref}, which is not an ray.ObjectRef.")
+    return core_worker.force_spill_objects(object_refs)
+
+
+def force_restore_spilled_objects(object_refs):
+    """Force restoring objects from external storage.
+
+    Args:
+        object_refs: Object refs of the objects to be
+            restored.
+    """
+    core_worker = ray.worker.global_worker.core_worker
+    # Make sure that the values are object refs.
+    for object_ref in object_refs:
+        if not isinstance(object_ref, ray.ObjectRef):
+            raise TypeError(
+                f"Attempting to call `force_restore_spilled_objects` on the "
+                f"value {object_ref}, which is not an ray.ObjectRef.")
+    return core_worker.force_restore_spilled_objects(object_refs)