wip @defer support

.gitignore

@@ -4,4 +4,5 @@
 .DS_Store
 pkg/parser/testdata/lotto.graphql
 *node_modules*
-*vendor*
+*vendor*
+.vscode

.markdownlint.yaml

@@ -0,0 +1,16 @@
+# Allow for code examples.
+no-hard-tabs:
+  code_blocks: false
+
+# Long lines are OK.
+line-length: false
+
+# We get excited!
+no-trailing-punctuation:
+  punctuation: ".,;:"
+
+# Allow inline HTML.
+no-inline-html: false
+
+# We lead with badges, it looks right.
+first-line-h1: false

README.md

@@ -1,8 +1,9 @@
 [![GoDoc](https://pkg.go.dev/badge/github.com/wundergraph/graphql-go-tools/v2)](https://pkg.go.dev/github.com/wundergraph/graphql-go-tools/v2)
 [![v2-ci](https://github.com/wundergraph/graphql-go-tools/workflows/v2-ci/badge.svg)](https://github.com/wundergraph/graphql-go-tools/actions/workflows/v2.yml)
+
 # GraphQL Router / API Gateway Framework written in Golang
 
-[<p align="center"><img height="auto" src="./assets/logo.png"></p>](https://wundergraph.com/)
+[<p align="center"><img height="auto" src="./assets/logo.png" alt="Wundergraph logo"></p>](https://wundergraph.com/)
 
 ## We're hiring!
 
@@ -19,6 +20,7 @@ If you're looking for a complete ready-to-use Open Source Router for Federation,
 have a look at the [Cosmo Router](https://github.com/wundergraph/cosmo) which is based on this library.
 
 Cosmo Router wraps this library and provides a complete solution for Federated GraphQL including the following features:
+
 - [x] Federation Gateway
 - [x] OpenTelemetry Metrics & Distributed Tracing
 - [x] Prometheus Metrics
@@ -44,7 +46,6 @@ This repository contains multiple packages joined via [workspace](https://github
 | [examples/federation](https://github.com/wundergraph/graphql-go-tools/blob/master/examples/federation/go.mod) | Example implementation of graphql federation gateway. This example is not production ready. For production ready solution please consider using [cosmo router](https://github.com/wundergraph/cosmo/tree/main)                     | depends on [execution](https://github.com/wundergraph/graphql-go-tools/blob/master/execution/go.mod) package                                                                                    | actual federation gateway example  |
 | [graphql-go-tools v1](https://github.com/wundergraph/graphql-go-tools/blob/master/go.mod)                     | Legacy GraphQL engine implementation. This version 1 package is in maintenance mode and accepts only pull requests with critical bug fixes. All new features will be implemented in the version 2 package only.                    | -                                                                                                                                                                                               | deprecated, maintenance mode       |
 
-
 ## Notes
 
 This library is used in production at [WunderGraph](https://wundergraph.com/).
@@ -298,7 +299,7 @@ func ExampleNormalizeDocument() {
 			hello: String
 			foo: Foo
 		}
-	
+
 		type Foo {
 			bar: String
 		}
@@ -534,7 +535,7 @@ func ExamplePlanOperation() {
 	if err != nil {
 		panic(err)
     }
-  
+
     config := plan.Configuration{
       DataSources: []plan.DataSource{
         staticDataSource,

execution/engine/execution_engine.go

@@ -231,6 +231,8 @@ func (e *ExecutionEngine) Execute(ctx context.Context, operation *graphql.Reques
 		return err
 	case *plan.SubscriptionResponsePlan:
 		return e.resolver.ResolveGraphQLSubscription(execContext.resolveContext, p.Response, writer)
+	case *plan.IncrementalResponsePlan:
+		return e.resolver.ResolveGraphQLIncrementalResponse(execContext.resolveContext, p.Response, writer)
 	default:
 		return errors.New("execution of operation is not possible")
 	}

v2/pkg/engine/plan/analyze_plan_kind.go

@@ -41,11 +41,14 @@ func (p *planKindVisitor) EnterDirective(ref int) {
 	switch ancestor.Kind {
 	case ast.NodeKindField:
 		switch directiveName {
-		case "defer":
-			p.hasDeferDirective = true
 		case "stream":
 			p.hasStreamDirective = true
 		}
+	case ast.NodeKindInlineFragment:
+		switch directiveName {
+		case "defer":
+			p.hasStreamDirective = true
+		}
 	}
 }
 

v2/pkg/engine/plan/analyze_plan_kind_test.go

@@ -100,7 +100,9 @@ func TestAnalyzePlanKind(t *testing.T) {
 					name
 				}
 				primaryFunction
-				favoriteEpisode @defer
+				... @defer {
+					favoriteEpisode
+				}
 			}
 		}`,
 		"MyQuery",
@@ -146,7 +148,9 @@ func TestAnalyzePlanKind(t *testing.T) {
 					name
 				}
 				primaryFunction
-				favoriteEpisode @defer
+				... @defer {
+					favoriteEpisode
+				}
 			}
 		}`,
 		"OperationNameNotExists",
@@ -167,7 +171,9 @@ func TestAnalyzePlanKind(t *testing.T) {
 		subscription NewReviews {
 			newReviews {
 				id
-				stars @defer
+				... @defer {
+					stars
+				}
 			}
 		}`,
 		"NewReviews",

v2/pkg/engine/plan/plan.go

@@ -9,6 +9,7 @@ type Kind int
 const (
 	SynchronousResponseKind Kind = iota + 1
 	SubscriptionResponseKind
+	IncrementalResponseKind
 )
 
 type Plan interface {
@@ -29,6 +30,19 @@ func (_ *SynchronousResponsePlan) PlanKind() Kind {
 	return SynchronousResponseKind
 }
 
+type IncrementalResponsePlan struct {
+	Response      *resolve.GraphQLIncrementalResponse
+	FlushInterval int64
+}
+
+func (s *IncrementalResponsePlan) SetFlushInterval(interval int64) {
+	s.FlushInterval = interval
+}
+
+func (_ *IncrementalResponsePlan) PlanKind() Kind {
+	return IncrementalResponseKind
+}
+
 type SubscriptionResponsePlan struct {
 	Response      *resolve.GraphQLSubscription
 	FlushInterval int64

v2/pkg/engine/plan/planner_test.go

@@ -304,6 +304,164 @@ func TestPlanner_Plan(t *testing.T) {
 		}))
 	})
 
+	t.Run("defer planning", func(t *testing.T) {
+		t.Run("inline fragment", test(testDefinition, `
+			query WithInlineDefer {
+				hero {
+					name
+					... on Droid @defer {
+						primaryFunction
+						favoriteEpisode
+					}
+				}
+			}
+		`, "WithInlineDefer", &IncrementalResponsePlan{
+			Response: &resolve.GraphQLIncrementalResponse{
+				ImmediateResponse: &resolve.GraphQLResponse{
+					Data: &resolve.Object{
+						Nullable: false,
+						Fields: []*resolve.Field{
+							{
+								Name: []byte("hero"),
+								Value: &resolve.Object{
+									Path:          []string{"hero"},
+									Nullable:      true,
+									TypeName:      "Character",
+									PossibleTypes: map[string]struct{}{"Droid": {}, "Human": {}},
+									Fields: []*resolve.Field{
+										{
+											Name: []byte("name"),
+											Value: &resolve.String{
+												Path:     []string{"name"},
+												Nullable: false,
+											},
+										},
+										{
+											Name: []byte("primaryFunction"),
+											Value: &resolve.String{
+												Path:     []string{"primaryFunction"},
+												Nullable: false,
+											},
+											OnTypeNames: [][]byte{[]byte("Droid")},
+											Defer:       &resolve.DeferField{},
+										},
+										{
+											Name: []byte("favoriteEpisode"),
+											Value: &resolve.Enum{
+												Path:     []string{"favoriteEpisode"},
+												Nullable: true,
+												TypeName: "Episode",
+												Values: []string{
+													"NEWHOPE",
+													"EMPIRE",
+													"JEDI",
+												},
+											},
+											OnTypeNames: [][]byte{[]byte("Droid")},
+											Defer:       &resolve.DeferField{},
+										},
+									},
+								},
+							},
+						},
+						Fetches: []resolve.Fetch{
+							&resolve.SingleFetch{
+								FetchConfiguration: resolve.FetchConfiguration{
+									DataSource: &FakeDataSource{&StatefulSource{}},
+								},
+								DataSourceIdentifier: []byte("plan.FakeDataSource"),
+							},
+						},
+					},
+				},
+				DeferredResponse: nil,
+			},
+		}, Configuration{
+			DisableResolveFieldPositions: true,
+			DisableIncludeInfo:           true,
+			DataSources:                  []DataSource{testDefinitionDSConfiguration},
+		}))
+
+		t.Run("fragment spread", test(testDefinition, `
+			query WithFragmentSpread {
+				hero {
+					name
+					...droid @defer
+				}
+			}
+
+			fragment droid on Droid {
+				primaryFunction
+				favoriteEpisode
+			}
+		`, "WithFragmentSpread", &IncrementalResponsePlan{
+			Response: &resolve.GraphQLIncrementalResponse{
+				ImmediateResponse: &resolve.GraphQLResponse{
+					Data: &resolve.Object{
+						Nullable: false,
+						Fields: []*resolve.Field{
+							{
+								Name: []byte("hero"),
+								Value: &resolve.Object{
+									Path:          []string{"hero"},
+									Nullable:      true,
+									TypeName:      "Character",
+									PossibleTypes: map[string]struct{}{"Droid": {}, "Human": {}},
+									Fields: []*resolve.Field{
+										{
+											Name: []byte("name"),
+											Value: &resolve.String{
+												Path:     []string{"name"},
+												Nullable: false,
+											},
+										},
+										{
+											Name: []byte("primaryFunction"),
+											Value: &resolve.String{
+												Path:     []string{"primaryFunction"},
+												Nullable: false,
+											},
+											OnTypeNames: [][]byte{[]byte("Droid")},
+											Defer:       &resolve.DeferField{},
+										},
+										{
+											Name: []byte("favoriteEpisode"),
+											Value: &resolve.Enum{
+												Path:     []string{"favoriteEpisode"},
+												Nullable: true,
+												TypeName: "Episode",
+												Values: []string{
+													"NEWHOPE",
+													"EMPIRE",
+													"JEDI",
+												},
+											},
+											OnTypeNames: [][]byte{[]byte("Droid")},
+											Defer:       &resolve.DeferField{},
+										},
+									},
+								},
+							},
+						},
+						Fetches: []resolve.Fetch{
+							&resolve.SingleFetch{
+								FetchConfiguration: resolve.FetchConfiguration{
+									DataSource: &FakeDataSource{&StatefulSource{}},
+								},
+								DataSourceIdentifier: []byte("plan.FakeDataSource"),
+							},
+						},
+					},
+				},
+				DeferredResponse: nil,
+			},
+		}, Configuration{
+			DisableResolveFieldPositions: true,
+			DisableIncludeInfo:           true,
+			DataSources:                  []DataSource{testDefinitionDSConfiguration},
+		}))
+	})
+
 	t.Run("operation selection", func(t *testing.T) {
 		cfg := Configuration{
 			DataSources:        []DataSource{testDefinitionDSConfiguration},
@@ -379,7 +537,7 @@ func TestPlanner_Plan(t *testing.T) {
 						name
 					}
 				}
-		
+
 				query MyHero {
 					hero{
 						name
@@ -392,15 +550,15 @@ func TestPlanner_Plan(t *testing.T) {
 	t.Run("unescape response json", func(t *testing.T) {
 		schema := `
 			scalar JSON
-			
+
 			schema {
 				query: Query
 			}
-			
+
 			type Query {
 				hero: Character!
 			}
-			
+
 			type Character {
 				info: JSON!
 				infos: [JSON!]!
@@ -678,7 +836,9 @@ var testDefinitionDSConfiguration = dsb().
 
 const testDefinition = `
 
-directive @defer on FIELD
+directive @defer(label: String if: Boolean! = true) on FRAGMENT_SPREAD | INLINE_FRAGMENT
+
+directive @stream(label: String if: Boolean! = true initialCount: Int = 0) on FIELD
 
 directive @flushInterval(milliSeconds: Int!) on QUERY | SUBSCRIPTION