feat: add tag directive from federation v2 (#210)

* Add tag directive from federation v2

* Add tag to union types

* Add tag to enum and enum value

* Fix style issues

* Add tags to scalar

* Support multiple tags per field

* Add tag to input objects

* Add tag support for arguments and input fields

* Remove trailing line

* fix: rubocop + tests

* feat: ensure @tag is not namespaced

---------

Co-authored-by: Grex <[email protected]>
Co-authored-by: Grex <[email protected]>

Author: dweinand

README.md

@@ -222,6 +222,26 @@ class Product < BaseObject
 end
 ```
 
+### The `@tag` directive (Apollo Federation v2)
+
+[Apollo documentation](https://www.apollographql.com/docs/federation/federated-types/federated-directives/#tag)
+
+Call `tag` within your class definition:
+
+```ruby
+class User < BaseObject
+  tag name: 'private'
+end
+```
+
+Pass the `tags:` option to your field definition:
+
+```ruby
+class User < BaseObject
+  field :id, ID, null: false, tags: [{ name: 'private' }]
+end
+```
+
 ### Field set syntax
 
 Field sets can be either strings encoded with the Apollo Field Set [syntax]((https://www.apollographql.com/docs/apollo-server/federation/federation-spec/#scalar-_fieldset)) or arrays, hashes and snake case symbols that follow the graphql-ruby conventions:

lib/apollo-federation.rb

@@ -4,7 +4,13 @@
 require 'apollo-federation/schema'
 require 'apollo-federation/object'
 require 'apollo-federation/interface'
+require 'apollo-federation/union'
+require 'apollo-federation/enum'
+require 'apollo-federation/enum_value'
 require 'apollo-federation/field'
+require 'apollo-federation/scalar'
+require 'apollo-federation/input_object'
+require 'apollo-federation/argument'
 require 'apollo-federation/tracing/proto'
 require 'apollo-federation/tracing/node_map'
 require 'apollo-federation/tracing/tracer'

lib/apollo-federation/argument.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require 'apollo-federation/has_directives'
+
+module ApolloFederation
+  module Argument
+    include HasDirectives
+
+    VERSION_2_DIRECTIVES = %i[tags].freeze
+
+    def initialize(*args, **kwargs, &block)
+      add_v2_directives(**kwargs)
+
+      # Remove the custom kwargs
+      kwargs = kwargs.delete_if do |k, _|
+        VERSION_2_DIRECTIVES.include?(k)
+      end
+
+      # Pass on the default args:
+      super(*args, **kwargs, &block)
+    end
+
+    private
+
+    def add_v2_directives(tags: [], **_kwargs)
+      tags.each do |tag|
+        add_directive(
+          name: 'tag',
+          arguments: [
+            name: 'name',
+            values: tag[:name],
+          ],
+        )
+      end
+    end
+  end
+end

lib/apollo-federation/enum.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require 'apollo-federation/has_directives'
+
+module ApolloFederation
+  module Enum
+    def self.included(klass)
+      klass.extend(ClassMethods)
+    end
+
+    module ClassMethods
+      include HasDirectives
+
+      def tag(name:)
+        add_directive(name: 'tag', arguments: [name: 'name', values: name])
+      end
+    end
+  end
+end

lib/apollo-federation/enum_value.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require 'apollo-federation/has_directives'
+
+module ApolloFederation
+  module EnumValue
+    include HasDirectives
+
+    VERSION_2_DIRECTIVES = %i[tags].freeze
+
+    def initialize(*args, **kwargs, &block)
+      add_v2_directives(**kwargs)
+
+      # Remove the custom kwargs
+      kwargs = kwargs.delete_if do |k, _|
+        VERSION_2_DIRECTIVES.include?(k)
+      end
+
+      # Pass on the default args:
+      super(*args, **kwargs, &block)
+    end
+
+    private
+
+    def add_v2_directives(tags: [], **_kwargs)
+      tags.each do |tag|
+        add_directive(
+          name: 'tag',
+          arguments: [
+            name: 'name',
+            values: tag[:name],
+          ],
+        )
+      end
+    end
+  end
+end

lib/apollo-federation/federated_document_from_schema_definition.rb

@@ -14,7 +14,6 @@ class FederatedDocumentFromSchemaDefinition < GraphQL::Language::DocumentFromSch
       '_entities',
       '_service',
     ].freeze
-    INACCESSIBLE_DIRECTIVE = 'inaccessible'
 
     def build_object_type_node(object_type)
       object_node = super
@@ -28,8 +27,38 @@ def build_object_type_node(object_type)
     end
 
     def build_interface_type_node(interface_type)
-      field_node = super
-      merge_directives(field_node, interface_type)
+      interface_node = super
+      merge_directives(interface_node, interface_type)
+    end
+
+    def build_union_type_node(union_type)
+      union_node = super
+      merge_directives(union_node, union_type)
+    end
+
+    def build_enum_type_node(enum_type)
+      enum_node = super
+      merge_directives(enum_node, enum_type)
+    end
+
+    def build_enum_value_node(enum_value_type)
+      enum_value_node = super
+      merge_directives(enum_value_node, enum_value_type)
+    end
+
+    def build_scalar_type_node(scalar_type)
+      scalar_node = super
+      merge_directives(scalar_node, scalar_type)
+    end
+
+    def build_input_object_node(input_object_type)
+      input_object_node = super
+      merge_directives(input_object_node, input_object_type)
+    end
+
+    def build_argument_node(argument_type)
+      argument_node = super
+      merge_directives(argument_node, argument_type)
     end
 
     def build_field_node(field_type)
@@ -71,7 +100,7 @@ def merge_directives(node, type)
     end
 
     def directive_name(directive)
-      if schema.federation_2? && directive[:name] != INACCESSIBLE_DIRECTIVE
+      if schema.federation_2? && !Schema::IMPORTED_DIRECTIVES.include?(directive[:name])
         "#{schema.link_namespace}__#{directive[:name]}"
       else
         directive[:name]

lib/apollo-federation/field.rb

@@ -8,7 +8,7 @@ module Field
     include HasDirectives
 
     VERSION_1_DIRECTIVES = %i[external requires provides].freeze
-    VERSION_2_DIRECTIVES = %i[shareable inaccessible override].freeze
+    VERSION_2_DIRECTIVES = %i[shareable inaccessible override tags].freeze
 
     def initialize(*args, **kwargs, &block)
       add_v1_directives(**kwargs)
@@ -59,7 +59,7 @@ def add_v1_directives(external: nil, requires: nil, provides: nil, **_kwargs)
       nil
     end
 
-    def add_v2_directives(shareable: nil, inaccessible: nil, override: nil, **_kwargs)
+    def add_v2_directives(shareable: nil, inaccessible: nil, override: nil, tags: [], **_kwargs)
       if shareable
         add_directive(name: 'shareable')
       end
@@ -78,6 +78,16 @@ def add_v2_directives(shareable: nil, inaccessible: nil, override: nil, **_kwarg
         )
       end
 
+      tags.each do |tag|
+        add_directive(
+          name: 'tag',
+          arguments: [
+            name: 'name',
+            values: tag[:name],
+          ],
+        )
+      end
+
       nil
     end
   end

lib/apollo-federation/input_object.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require 'apollo-federation/has_directives'
+
+module ApolloFederation
+  module InputObject
+    def self.included(klass)
+      klass.extend(ClassMethods)
+    end
+
+    module ClassMethods
+      include HasDirectives
+
+      def tag(name:)
+        add_directive(name: 'tag', arguments: [name: 'name', values: name])
+      end
+    end
+  end
+end

lib/apollo-federation/interface.rb

@@ -22,6 +22,10 @@ def inaccessible
         add_directive(name: 'inaccessible')
       end
 
+      def tag(name:)
+        add_directive(name: 'tag', arguments: [name: 'name', values: name])
+      end
+
       def key(fields:, camelize: true)
         add_directive(
           name: 'key',

lib/apollo-federation/object.rb

@@ -28,6 +28,10 @@ def interface_object
         add_directive(name: 'interfaceObject')
       end
 
+      def tag(name:)
+        add_directive(name: 'tag', arguments: [name: 'name', values: name])
+      end
+
       def key(fields:, camelize: true)
         add_directive(
           name: 'key',