feat: support @external on OBJECT type

graphene_federation/external.py

@@ -1,4 +1,5 @@
 from graphene import Schema
+from graphene.types.objecttype import ObjectTypeMeta
 
 from graphene_federation.utils import get_attributed_fields
 
@@ -7,7 +8,10 @@ def external(field):
     """
     Mark a field as external.
     """
-    field._external = True
+    if isinstance(field, ObjectTypeMeta):
+        field._external_entity = True
+    else:
+        field._external = True
     return field
 
 
@@ -18,3 +22,20 @@ def get_external_fields(schema: Schema) -> dict:
     the `@external` decorator adds a `_external` attribute to them.
     """
     return get_attributed_fields(attribute="_external", schema=schema)
+
+
+def get_external_object_types(schema: Schema) -> dict:
+    """
+    Find all the extended object types from the schema.
+    They can be easily distinguished from the other type as
+    the `@external` decorator adds a `_external_entity` attribute to them.
+    """
+    fields = {}
+
+    for type_name, type_ in schema.graphql_schema.type_map.items():
+        if hasattr(type_, "graphene_type") and hasattr(
+            type_.graphene_type, "_external_entity"
+        ):
+            fields[type_name] = type_
+
+    return fields

graphene_federation/service.py

@@ -6,7 +6,7 @@
 from graphql import GraphQLInterfaceType, GraphQLObjectType
 
 from .compose_directive import is_composable, compose_directive_schema_extensions
-from .external import get_external_fields
+from .external import get_external_fields, get_external_object_types
 from .inaccessible import get_inaccessible_types, get_inaccessible_fields
 from .override import get_override_fields
 from .requires import get_required_fields
@@ -134,6 +134,7 @@ def get_sdl(schema: Schema) -> str:
     entities = get_entities(schema)
     required_fields = get_required_fields(schema)
     external_fields = get_external_fields(schema)
+    external_object_types = get_external_object_types(schema)
     override_fields = get_override_fields(schema)
 
     schema_extensions = []
@@ -147,7 +148,7 @@ def get_sdl(schema: Schema) -> str:
 
         federation_spec_import = []
 
-        if extended_types:
+        if extended_types or external_object_types:
             federation_spec_import.append('"@extends"')
         if external_fields:
             federation_spec_import.append('"@external"')
@@ -244,6 +245,12 @@ def get_sdl(schema: Schema) -> str:
         string_schema = pattern.sub(repl_str, string_schema)
 
     if schema.federation_version >= 2:
+        # Add `@external` keyword to the type definition of external object types
+        for object_type_name, _ in external_object_types.items():
+            type_def = re.compile(rf"type {object_type_name} ([^{{]*)")
+            repl_str = rf"type {object_type_name} @external \1"
+            string_schema = type_def.sub(repl_str, string_schema)
+
         for type_name, type in shareable_types.items():
             # noinspection PyProtectedMember
             if isinstance(type._meta, UnionOptions):