Initial setup GraphQL using graphql-ruby 1.8

- All definitions have been replaced by classes:
  http://graphql-ruby.org/schema/class_based_api.html
- Authorization & Presentation have been refactored to work in the
  class based system
- Loaders have been replaced by resolvers
- Times are now coersed as ISO 8601

.rubocop.yml

@@ -43,7 +43,6 @@ Naming/FileName:
     - 'config/**/*'
     - 'lib/generators/**/*'
     - 'ee/lib/generators/**/*'
-    - 'app/graphql/**/*'
   IgnoreExecutableScripts: true
   AllowedAcronyms:
     - EE

Gemfile

@@ -94,8 +94,7 @@ gem 'grape-entity', '~> 0.7.1'
 gem 'rack-cors', '~> 1.0.0', require: 'rack/cors'
 # GraphQL API
-gem 'graphql', '~> 1.7.14'
-gem 'graphql-preload', '~> 2.0.0'
+gem 'graphql', '~> 1.8.0'
 gem 'graphiql-rails', '~> 1.4.10'
 # Disable strong_params so that Mash does not respond to :permitted?

Gemfile.lock

@@ -368,15 +368,7 @@ GEM
     graphiql-rails (1.4.10)
       railties
       sprockets-rails
-    graphql (1.7.14)
-    graphql-batch (0.3.9)
-      graphql (>= 0.8, < 2)
-      promise.rb (~> 0.7.2)
-    graphql-preload (2.0.1)
-      activerecord (>= 4.1, < 6)
-      graphql (>= 1.5, < 2)
-      graphql-batch (~> 0.3)
-      promise.rb (~> 0.7)
+    graphql (1.8.1)
     grpc (1.11.0)
       google-protobuf (~> 3.1)
       googleapis-common-protos-types (~> 1.0.0)
@@ -639,7 +631,6 @@ GEM
       unparser
     procto (0.0.3)
     prometheus-client-mmap (0.9.3)
-    promise.rb (0.7.4)
     pry (0.10.4)
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
@@ -1067,8 +1058,7 @@ DEPENDENCIES
   grape-path-helpers (~> 1.0)
   grape_logging (~> 1.7)
   graphiql-rails (~> 1.4.10)
-  graphql (~> 1.7.14)
-  graphql-preload (~> 2.0.0)
+  graphql (~> 1.8.0)
   grpc (~> 1.11.0)
   haml_lint (~> 0.26.0)
   hamlit (~> 2.6.1)

app/graphql/functions/base_function.rb

+module Functions
+  class BaseFunction < GraphQL::Function
+  end
+end

app/graphql/functions/echo.rb

+module Functions
+  class Echo < BaseFunction
+    argument :text, GraphQL::STRING_TYPE
+
+    description "Testing endpoint to validate the API with"
+
+    def call(obj, args, ctx)
+      username = ctx[:current_user]&.username
+
+      "#{username.inspect} says: #{args[:text]}"
+    end
+  end
+end

app/graphql/gitlab_schema.rb

-Gitlab::Graphql::Authorize.register!
-Gitlab::Graphql::Present.register!
-
-GitlabSchema = GraphQL::Schema.define do
+class GitlabSchema < GraphQL::Schema
   use BatchLoader::GraphQL
-
-  enable_preloading
-  enable_authorization
-  enable_presenting
+  use Gitlab::Graphql::Authorize
+  use Gitlab::Graphql::Present
   query(Types::QueryType)
+  # mutation(Types::MutationType)
 end

app/graphql/loaders/base_loader.rb

-# Helper methods for all loaders
-module Loaders::BaseLoader
-  extend ActiveSupport::Concern
-
-  class_methods do
-    # Convert a class method into a resolver proc. The method should follow the
-    # (obj, args, ctx) calling convention
-    def [](sym)
-      resolver = method(sym)
-      raise ArgumentError.new("#{self}.#{sym} is not a resolver") unless resolver.arity == 3
-
-      resolver
-    end
-  end
-end

app/graphql/loaders/iid_loader.rb

-class Loaders::IidLoader
-  include Loaders::BaseLoader
-
-  class << self
-    def merge_request(obj, args, ctx)
-      iid = args[:iid]
-      project = Loaders::FullPathLoader.project_by_full_path(args[:project])
-      merge_request_by_project_and_iid(project, iid)
-    end
-
-    def merge_request_by_project_and_iid(project_loader, iid)
-      project_id = project_loader.__sync&.id
-
-      # IIDs are represented as the GraphQL `id` type, which is a string
-      BatchLoader.for(iid.to_s).batch(key: "merge_request:target_project:#{project_id}:iid") do |iids, loader|
-        if project_id
-          results = MergeRequest.where(target_project_id: project_id, iid: iids)
-          results.each { |mr| loader.call(mr.iid.to_s, mr) }
-        end
-      end
-    end
-  end
-end

app/graphql/resolvers/base_resolver.rb

+module Resolvers
+  class BaseResolver < GraphQL::Schema::Resolver
+  end
+end

app/graphql/loaders/full_path_loader.rb → app/graphql/resolvers/full_path_resolver.rb

-module Loaders::FullPathLoader
-  include Loaders::BaseLoader
-  class << self
-    def project(obj, args, ctx)
-      project_by_full_path(args[:full_path])
-    end
-
-    def project_by_full_path(full_path)
-      model_by_full_path(Project, full_path)
+module Resolvers
+  module FullPathResolver
+    extend ActiveSupport::Concern
+    prepended do
+      argument :full_path, GraphQL::ID_TYPE,
+               required: true,
+               description: 'The full path of the project or namespace, e.g., "gitlab-org/gitlab-ce"'
     end
     def model_by_full_path(model, full_path)

app/graphql/resolvers/merge_request_resolver.rb

+module Resolvers
+  class MergeRequestResolver < BaseResolver
+    prepend FullPathResolver
+
+    type Types::ProjectType, null: true
+
+    argument :iid, GraphQL::ID_TYPE,
+             required: true,
+             description: 'The IID of the merge request, e.g., "1"'
+
+    def resolve(full_path:, iid:)
+      project = model_by_full_path(Project, full_path)
+      return unless project.present?
+
+      BatchLoader.for(iid.to_s).batch(key: project.id) do |iids, loader|
+        results = project.merge_requests.where(iid: iids)
+        results.each { |mr| loader.call(mr.iid.to_s, mr) }
+      end
+    end
+  end
+end

app/graphql/resolvers/project_resolver.rb

+module Resolvers
+  class ProjectResolver < BaseResolver
+    prepend FullPathResolver
+
+    type Types::ProjectType, null: true
+
+    def resolve(full_path:)
+      model_by_full_path(Project, full_path)
+    end
+  end
+end

app/graphql/types/base_enum.rb

+module Types
+  class BaseEnum < GraphQL::Schema::Enum
+  end
+end

app/graphql/types/base_field.rb

+module Types
+  class BaseField < GraphQL::Schema::Field
+    prepend Gitlab::Graphql::Authorize
+  end
+end

app/graphql/types/base_input_object.rb

+module Types
+  class BaseInputObject < GraphQL::Schema::InputObject
+  end
+end

app/graphql/types/base_interface.rb

+module Types
+  module BaseInterface
+    include GraphQL::Schema::Interface
+  end
+end

app/graphql/types/base_object.rb

+module Types
+  class BaseObject < GraphQL::Schema::Object
+    prepend Gitlab::Graphql::Present
+
+    field_class Types::BaseField
+  end
+end

app/graphql/types/base_scalar.rb

+module Types
+  class BaseScalar < GraphQL::Schema::Scalar
+  end
+end

app/graphql/types/base_union.rb

+module Types
+  class BaseUnion < GraphQL::Schema::Union
+  end
+end

app/graphql/types/merge_request_type.rb

-Types::MergeRequestType = GraphQL::ObjectType.define do
-  present_using MergeRequestPresenter
-  name 'MergeRequest'
-  field :id, !types.ID
-  field :iid, !types.ID
-  field :title, !types.String
-  field :description, types.String
-  field :state, types.String
-  field :created_at, !Types::TimeType
-  field :updated_at, !Types::TimeType
-  field :source_project, Types::ProjectType
-  field :target_project, !Types::ProjectType
-  # Alias for target_project
-  field :project, !Types::ProjectType
-  field :project_id, !types.Int, property: :target_project_id
-  field :source_project_id, types.Int
-  field :target_project_id, !types.Int
-  field :source_branch, !types.String
-  field :target_branch, !types.String
-  field :work_in_progress, types.Boolean, property: :work_in_progress?
-  field :merge_when_pipeline_succeeds, types.Boolean
-  field :sha, types.String, property: :diff_head_sha
-  field :merge_commit_sha, types.String
-  field :user_notes_count, types.Int
-  field :should_remove_source_branch, types.Boolean, property: :should_remove_source_branch?
-  field :force_remove_source_branch, types.Boolean, property: :force_remove_source_branch?
-  field :merge_status, types.String
-  field :in_progress_merge_commit_sha, types.String
-  field :merge_error, types.String
-  field :allow_maintainer_to_push, types.Boolean
-  field :should_be_rebased, types.Boolean, property: :should_be_rebased?
-  field :rebase_commit_sha, types.String
-  field :rebase_in_progress, types.Boolean, property: :rebase_in_progress?
-  field :diff_head_sha, types.String
-  field :merge_commit_message, types.String
-  field :merge_ongoing, types.Boolean, property: :merge_ongoing?
-  field :work_in_progress, types.Boolean, property: :work_in_progress?
-  field :source_branch_exists, types.Boolean, property: :source_branch_exists?
-  field :mergeable_discussions_state, types.Boolean
-  field :web_url, types.String, property: :web_url
-  field :upvotes, types.Int
-  field :downvotes, types.Int
-  field :subscribed, types.Boolean, property: :subscribed?
+module Types
+  class MergeRequestType < BaseObject
+    present_using MergeRequestPresenter
+    graphql_name 'MergeRequest'
+    field :id, GraphQL::ID_TYPE, null: false
+    field :iid, GraphQL::ID_TYPE, null: false
+    field :title, GraphQL::STRING_TYPE, null: false
+    field :description, GraphQL::STRING_TYPE, null: true
+    field :state, GraphQL::STRING_TYPE, null: true
+    field :created_at, Types::TimeType, null: false
+    field :updated_at, Types::TimeType, null: false
+    field :source_project, Types::ProjectType, null: true
+    field :target_project, Types::ProjectType, null: false
+    # Alias for target_project
+    field :project, Types::ProjectType, null: false
+    field :project_id, GraphQL::INT_TYPE, null: false, method: :target_project_id
+    field :source_project_id, GraphQL::INT_TYPE, null: true
+    field :target_project_id, GraphQL::INT_TYPE, null: false
+    field :source_branch, GraphQL::STRING_TYPE, null: false
+    field :target_branch, GraphQL::STRING_TYPE, null: false
+    field :work_in_progress, GraphQL::BOOLEAN_TYPE, method: :work_in_progress?, null: false
+    field :merge_when_pipeline_succeeds, GraphQL::BOOLEAN_TYPE, null: true
+    field :diff_head_sha, GraphQL::STRING_TYPE, null: true
+    field :merge_commit_sha, GraphQL::STRING_TYPE, null: true
+    field :user_notes_count, GraphQL::INT_TYPE, null: true
+    field :should_remove_source_branch, GraphQL::BOOLEAN_TYPE, method: :should_remove_source_branch?, null: true
+    field :force_remove_source_branch, GraphQL::BOOLEAN_TYPE, method: :force_remove_source_branch?, null: true
+    field :merge_status, GraphQL::STRING_TYPE, null: true
+    field :in_progress_merge_commit_sha, GraphQL::STRING_TYPE, null: true
+    field :merge_error, GraphQL::STRING_TYPE, null: true
+    field :allow_collaboration, GraphQL::BOOLEAN_TYPE, null: true
+    field :should_be_rebased, GraphQL::BOOLEAN_TYPE, method: :should_be_rebased?, null: false
+    field :rebase_commit_sha, GraphQL::STRING_TYPE, null: true
+    field :rebase_in_progress, GraphQL::BOOLEAN_TYPE, method: :rebase_in_progress?, null: false
+    field :diff_head_sha, GraphQL::STRING_TYPE, null: true
+    field :merge_commit_message, GraphQL::STRING_TYPE, null: true
+    field :merge_ongoing, GraphQL::BOOLEAN_TYPE, method: :merge_ongoing?, null: false
+    field :source_branch_exists, GraphQL::BOOLEAN_TYPE, method: :source_branch_exists?, null: false
+    field :mergeable_discussions_state, GraphQL::BOOLEAN_TYPE, null: true
+    field :web_url, GraphQL::STRING_TYPE, null: true
+    field :upvotes, GraphQL::INT_TYPE, null: false
+    field :downvotes, GraphQL::INT_TYPE, null: false
+    field :subscribed, GraphQL::BOOLEAN_TYPE, method: :subscribed?, null: false
+  end
 end