Expose print_directive function to enable schema sharding

Replicates graphql/graphql-js@d45e48b

Author: Cito

docs/modules/utilities.rst

@@ -41,9 +41,10 @@ Sort a GraphQLSchema:
 
 Print a GraphQLSchema to GraphQL Schema language:
 
-.. autofunction:: print_introspection_schema
 .. autofunction:: print_schema
 .. autofunction:: print_type
+.. autofunction:: print_directive
+.. autofunction:: print_introspection_schema
 
 Create a GraphQLType from a GraphQL language AST:
 

src/graphql/__init__.py

@@ -188,6 +188,8 @@
     print_schema,
     # Print a GraphQLType to GraphQL Schema language.
     print_type,
+    # Print a GraphQLDirective to GraphQL Schema language.
+    print_directive,
     # Prints the built-in introspection schema in the Schema Language format.
     print_introspection_schema,
     # Create a GraphQLType from a GraphQL language AST.
@@ -788,6 +790,7 @@
     "lexicographic_sort_schema",
     "print_schema",
     "print_type",
+    "print_directive",
     "print_introspection_schema",
     "type_from_ast",
     "value_from_ast",

src/graphql/utilities/__init__.py

@@ -27,9 +27,10 @@
 
 # Print a GraphQLSchema to GraphQL Schema language.
 from .print_schema import (
-    print_introspection_schema,
     print_schema,
     print_type,
+    print_directive,
+    print_introspection_schema,
     print_value,  # deprecated
 )
 
@@ -103,9 +104,10 @@
     "is_type_sub_type_of",
     "introspection_from_schema",
     "lexicographic_sort_schema",
-    "print_introspection_schema",
     "print_schema",
     "print_type",
+    "print_directive",
+    "print_introspection_schema",
     "print_value",
     "separate_operations",
     "strip_ignored_characters",

src/graphql/utilities/print_schema.py

@@ -32,7 +32,13 @@
 )
 from .ast_from_value import ast_from_value
 
-__all__ = ["print_schema", "print_introspection_schema", "print_type", "print_value"]
+__all__ = [
+    "print_schema",
+    "print_type",
+    "print_directive",
+    "print_introspection_schema",
+    "print_value",
+]
 
 
 def print_schema(schema: GraphQLSchema) -> str: