export scalars in sdl

hiku/federation/scalars.py

@@ -1,11 +1,21 @@
-from typing import Any
+from typing import Any, Callable, List, Type
 
 from hiku.scalar import Scalar, scalar
 
 
+def federation_version(versions: List[int]) -> Callable[[Type], Type]:
+    def decorator(cls: Type[_Scalar]) -> Type[_Scalar]:
+        cls.__federation_versions__ = versions
+        return cls
+
+    return decorator
+
+
 class _Scalar(Scalar):
     """Implements dummy `parse` and `serialize` methods for scalars."""
 
+    __federation_versions__: List[int]
+
     @classmethod
     def parse(cls, value: str) -> Any:
         return value
@@ -15,15 +25,18 @@ def serialize(cls, value: str) -> Any:
         return value
 
 
+@federation_version([2])
 class _Any(_Scalar):
     ...
 
 
+@federation_version([1, 2])
 @scalar(name="_FieldSet")
 class FieldSet(_Scalar):
     ...
 
 
+@federation_version([2])
 @scalar(name="link__Import")
 class LinkImport(_Scalar):
     ...

hiku/federation/sdl.py

@@ -53,13 +53,16 @@
     GenericMeta,
 )
 
+
+def _name(value: t.Optional[str]) -> t.Optional[ast.NameNode]:
+    return ast.NameNode(value=value) if value is not None else None
+
+
 _BUILTIN_DIRECTIVES_NAMES = {
     directive.__directive_info__.name for directive in _BUILTIN_DIRECTIVES
 }
 
-
-def _name(value: t.Optional[str]) -> t.Optional[ast.NameNode]:
-    return ast.NameNode(value=value) if value is not None else None
+_BUILTIN_SCALARS = [ast.ScalarTypeDefinitionNode(name=_name("Any"))]
 
 
 @t.overload
@@ -237,7 +240,7 @@ def visit_graph(self, graph: Graph) -> List[ast.DefinitionNode]:
                 if self.mutation_graph
                 else []
             ),
-            self.get_any_scalar(),
+            *self.export_scalars(),
             *self.export_enums(),
             *self.export_unions(),
             self.get_service_type(),
@@ -373,8 +376,22 @@ def get_custom_directives(self) -> t.List[ast.DirectiveDefinitionNode]:
             )
         return directives
 
-    def get_any_scalar(self) -> ast.ScalarTypeDefinitionNode:
-        return ast.ScalarTypeDefinitionNode(name=_name("Any"))
+    def export_scalars(self) -> t.List[ast.ScalarTypeDefinitionNode]:
+        scalars = []
+        for scalar in self.graph.scalars:
+            if hasattr(scalar, "__federation_versions__"):
+                if (
+                    self.federation_version
+                    not in scalar.__federation_versions__
+                ):  # noqa: E501
+                    continue
+
+            scalars.append(
+                ast.ScalarTypeDefinitionNode(
+                    name=_name(scalar.__type_name__),
+                )
+            )
+        return _BUILTIN_SCALARS + scalars
 
     def export_enums(self) -> t.List[ast.EnumTypeDefinitionNode]:
         enums = []

tests/test_federation/test_sdl_v1.py

@@ -100,6 +100,8 @@ def execute(graph, query_string):
     }
 
     scalar Any
+
+    scalar _FieldSet
 
     union Bucket = Cart
 

tests/test_federation/test_sdl_v2.py

@@ -1,4 +1,5 @@
 import textwrap
+from typing import Any
 
 from hiku.directives import Location
 from hiku.enum import Enum
@@ -16,6 +17,7 @@
     TypeRef,
     Optional,
 )
+from hiku.scalar import Scalar
 from hiku.graph import apply
 
 from hiku.federation.graph import FederatedNode, Graph
@@ -41,6 +43,16 @@ class Custom(FederationSchemaDirective):
     ...
 
 
+class Long(Scalar):
+    @classmethod
+    def parse(cls, value: Any) -> int:
+        return int(value)
+
+    @classmethod
+    def serialize(cls, value: Any) -> int:
+        return int(value)
+
+
 SaveOrderResultNode = Node(
     "SaveOrderResult",
     [
@@ -62,6 +74,7 @@ class Custom(FederationSchemaDirective):
     ], directives=[Key('id')]),
     FederatedNode('CartItem', [
         Field('id', Integer, field_resolver),
+        Field('productId', Long, field_resolver),
     ], directives=[Key('id', resolvable=False)]),
     Root([
         Link(
@@ -83,7 +96,7 @@ class Custom(FederationSchemaDirective):
     Union('Bucket', ['Cart'])
 ], enums=[
     Enum('Currency', ['UAH', 'USD'])
-])
+], scalars=[Long])
 
 
 MUTATION_GRAPH = Graph.from_graph(
@@ -135,6 +148,7 @@ class Custom(FederationSchemaDirective):
 
     type CartItem @key(fields: "id", resolvable: false) {
       id: Int!
+      productId: Long!
     }
 
     extend type Query {
@@ -143,6 +157,14 @@ class Custom(FederationSchemaDirective):
     %s
     scalar Any
 
+    scalar Long
+
+    scalar _Any
+
+    scalar _FieldSet
+
+    scalar link__Import
+
     enum Currency {
       UAH
       USD