Concurrent Resolvers

main.go

package main
import (    "encoding/json"    "fmt"    "log"
    "github.com/graphql-go/graphql")
type Foo struct {    Name string}
var FieldFooType = graphql.NewObject(graphql.ObjectConfig{    Name: "Foo",    Fields: graphql.Fields{        "name": &graphql.Field{Type: graphql.String},    },})
type Bar struct {    Name string}
var FieldBarType = graphql.NewObject(graphql.ObjectConfig{    Name: "Bar",    Fields: graphql.Fields{        "name": &graphql.Field{Type: graphql.String},    },})
// QueryType fields: `concurrentFieldFoo` and `concurrentFieldBar` are resolved// concurrently because they belong to the same field-level and their `Resolve`// function returns a function (thunk).var QueryType = graphql.NewObject(graphql.ObjectConfig{    Name: "Query",    Fields: graphql.Fields{        "concurrentFieldFoo": &graphql.Field{            Type: FieldFooType,            Resolve: func(p graphql.ResolveParams) (interface{}, error) {                var foo = Foo{Name: "Foo's name"}                return func() (interface{}, error) {                    return &foo, nil                }, nil            },        },        "concurrentFieldBar": &graphql.Field{            Type: FieldBarType,            Resolve: func(p graphql.ResolveParams) (interface{}, error) {                type result struct {                    data interface{}                    err  error                }                ch := make(chan *result, 1)                go func() {                    defer close(ch)                    bar := &Bar{Name: "Bar's name"}                    ch <- &result{data: bar, err: nil}                }()                return func() (interface{}, error) {                    r := <-ch                    return r.data, r.err                }, nil            },        },    },})
func main() {    schema, err := graphql.NewSchema(graphql.SchemaConfig{        Query: QueryType,    })    if err != nil {        log.Fatal(err)    }    query := `        query {            concurrentFieldFoo {                name            }            concurrentFieldBar {                name            }        }    `    result := graphql.Do(graphql.Params{        RequestString: query,        Schema:        schema,    })    b, err := json.Marshal(result)    if err != nil {        log.Fatal(err)    }    fmt.Printf("%s", b)    /*        {          "data": {            "concurrentFieldBar": {              "name": "Bar's name"            },            "concurrentFieldFoo": {              "name": "Foo's name"            }          }        }    */}