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feat: allow query cancellation #19

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123 changes: 73 additions & 50 deletions executor.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ package graphql

import (
"encoding/json"
"errors"
"fmt"
"math"
"reflect"
Expand All @@ -13,16 +14,18 @@ import (

. "github.com/playlyfe/go-graphql/language"
"github.com/playlyfe/go-graphql/utils"
nctx "golang.org/x/net/context"
)

type ResolveParams struct {
Executor *Executor
Request *Document
Schema *Document
Context interface{}
Source interface{}
Args map[string]interface{}
Field *Field
Executor *Executor
Request *Document
Schema *Document
Context interface{}
RequestContext nctx.Context
Source interface{}
Args map[string]interface{}
Field *Field
}

type Error struct {
Expand All @@ -42,6 +45,7 @@ func (list *ErrorList) Add(err *Error) {
}

type RequestContext struct {
NetContext nctx.Context
AppContext interface{}
Document *Document
ErrorList *ErrorList
Expand Down Expand Up @@ -84,6 +88,8 @@ type GroupedField struct {
Fields []*Field
}

var ContextDoneErr error = errors.New("Context canceled / done before query complete.")

/**
* Prepares an object map of variableValues of the correct type based on the
* provided variable definitions and arbitrary input. If the input cannot be
Expand Down Expand Up @@ -113,7 +119,6 @@ func (executor *Executor) resolveNamedType(ntype ASTNode) *NamedType {
return unmodifiedType.(*NamedType)
}
}
return nil
}

func (executor *Executor) printType(ttype ASTNode) string {
Expand All @@ -127,14 +132,6 @@ func (executor *Executor) printType(ttype ASTNode) string {
panic("Unexpected AST node type")
}

// TODO: Implement type printer
/*func PrintType (ntype ASTNode) string {
output := ""


}
}*/

/**
* Prepares an object map of argument values given a list of argument
* definitions and list of argument AST nodes.
Expand Down Expand Up @@ -292,7 +289,7 @@ func (executor *Executor) variableValue(context interface{}, ntype ASTNode, inpu
}
}
}
for key, _ := range object {
for key := range object {
if _, exists := inputType.FieldIndex[key]; !exists {
return nil, &GraphQLError{
Message: fmt.Sprintf("In field %q: Unknown field", key),
Expand Down Expand Up @@ -740,6 +737,10 @@ func handleGQLError(result map[string]interface{}, err error) (map[string]interf
}

func (executor *Executor) Execute(context interface{}, request string, variables map[string]interface{}, operationName string) (map[string]interface{}, error) {
return executor.ExecuteWithContext(context, request, variables, operationName, nil)
}

func (executor *Executor) ExecuteWithContext(context interface{}, request string, variables map[string]interface{}, operationName string, netContext nctx.Context) (map[string]interface{}, error) {
parser := &Parser{}
result := map[string]interface{}{}
document, err := parser.Parse(&ParseParams{
Expand All @@ -749,7 +750,17 @@ func (executor *Executor) Execute(context interface{}, request string, variables
return handleGQLError(result, err)
}

if netContext == nil {
netContext = nctx.Background()
}

subContext, cancelFn := nctx.WithCancel(netContext)
defer func() {
cancelFn()
}()

reqCtx := &RequestContext{
NetContext: subContext,
AppContext: context,
Document: document,
ErrorList: &ErrorList{},
Expand Down Expand Up @@ -782,10 +793,11 @@ func (executor *Executor) Execute(context interface{}, request string, variables
} else {
if executor.Before != nil {
err = executor.Before(&ResolveParams{
Executor: executor,
Schema: executor.Schema.Document,
Request: reqCtx.Document,
Context: reqCtx.AppContext,
RequestContext: reqCtx.NetContext,
Executor: executor,
Schema: executor.Schema.Document,
Request: reqCtx.Document,
Context: reqCtx.AppContext,
}, selectedOperation.Operation)
if err != nil {
result, err = handleGQLError(result, err)
Expand Down Expand Up @@ -824,10 +836,11 @@ func (executor *Executor) Execute(context interface{}, request string, variables

if executor.After != nil {
err = executor.After(&ResolveParams{
Executor: executor,
Schema: executor.Schema.Document,
Request: reqCtx.Document,
Context: reqCtx.AppContext,
RequestContext: reqCtx.NetContext,
Executor: executor,
Schema: executor.Schema.Document,
Request: reqCtx.Document,
Context: reqCtx.AppContext,
}, result)
if err != nil {
return nil, err
Expand All @@ -838,12 +851,10 @@ func (executor *Executor) Execute(context interface{}, request string, variables
}

func (executor *Executor) selectionSet(reqCtx *RequestContext, isParallel bool, objectType *ObjectTypeDefinition, source interface{}, selectionSet *SelectionSet) (map[string]interface{}, error) {
//log.Printf("collecting fields")
groupedFields, err := executor.collectFields(reqCtx, objectType, selectionSet, &utils.Set{})
if err != nil {
return nil, err
}
//log.Printf("resolving fields")
return executor.resolveGroupedFields(reqCtx, isParallel, objectType, source, groupedFields)

}
Expand Down Expand Up @@ -1040,15 +1051,24 @@ func (executor *Executor) doesFragmentTypeApply(objectType *ObjectTypeDefinition
func (executor *Executor) resolveGroupedFields(reqCtx *RequestContext, isParallel bool, objectType *ObjectTypeDefinition, source interface{}, groupedFields []*GroupedField) (map[string]interface{}, error) {
result := map[string]interface{}{}

// TODO: Use go routines?
if isParallel && !executor.Debug {
doneCh := reqCtx.NetContext.Done()
errs := []error{}
panics := []interface{}{}
wg := sync.WaitGroup{}
mutex := sync.Mutex{}
errMutex := sync.Mutex{}
contextCanceled := false

GroupedFieldsLoop:
for _, groupForResponseKey := range groupedFields {
//log.Printf("evaluating field entry for '%s'", responseKey)
select {
case <-doneCh:
contextCanceled = true
break GroupedFieldsLoop
default:
}

wg.Add(1)
go func(responseKey string, fields []*Field) {
defer func() {
Expand All @@ -1066,9 +1086,7 @@ func (executor *Executor) resolveGroupedFields(reqCtx *RequestContext, isParalle
errs = append(errs, err)
errMutex.Unlock()
}
//log.Printf("Adding '%s' with value '%#v' to response", key, value)
if key != "" {
//log.Printf("Adding key '%s' with value '%#v' to response", responseKey, value)
mutex.Lock()
result[responseKey] = value
mutex.Unlock()
Expand All @@ -1082,18 +1100,16 @@ func (executor *Executor) resolveGroupedFields(reqCtx *RequestContext, isParalle
}
if len(errs) > 0 {
return nil, errs[0]
} else if contextCanceled {
return nil, ContextDoneErr
}

} else {
for _, groupForResponseKey := range groupedFields {
//log.Printf("evaluating field entry for '%s'", responseKey)
key, value, err := executor.getFieldEntry(reqCtx, objectType, source, groupForResponseKey.ResponseKey, groupForResponseKey.Fields)
if err != nil {
return nil, err
}
//log.Printf("Adding '%s' with value '%#v' to response", key, value)
if key != "" {
//log.Printf("Adding key '%s' with value '%#v' to response", responseKey, value)
result[groupForResponseKey.ResponseKey] = value
}
}
Expand All @@ -1103,14 +1119,11 @@ func (executor *Executor) resolveGroupedFields(reqCtx *RequestContext, isParalle

func (executor *Executor) getFieldEntry(reqCtx *RequestContext, objectType *ObjectTypeDefinition, object interface{}, responseKey string, fields []*Field) (string, interface{}, error) {
firstField := fields[0]
//log.Printf("Test %#v", firstField.Name.Value)
fieldType := executor.getFieldTypeFromObjectType(objectType, firstField)
if fieldType == nil {
//log.Printf("field type of selection '%s' could not be determined", firstField.Name.Value)
return "", nil, nil
}
resolvedObject, err := executor.resolveFieldOnObject(reqCtx, objectType, object, fieldType, firstField)
//log.Printf("field %s resolved to %#v", firstField.Name.Value, resolvedObject)
if err != nil {
return "", nil, err
}
Expand Down Expand Up @@ -1161,12 +1174,9 @@ func (executor *Executor) completeValueCatchingError(reqCtx *RequestContext, obj
}

func (executor *Executor) completeValue(reqCtx *RequestContext, objectType *ObjectTypeDefinition, fieldType ASTNode, field *Field, result interface{}, subSelectionSet *SelectionSet) (interface{}, error) {
//var err error
//log.Printf("completing value on %#v", result)
if nonNullType, ok := fieldType.(*NonNullType); ok {
innerType := nonNullType.Type
completedResult, err := executor.completeValue(reqCtx, objectType, innerType, field, result, subSelectionSet)
//log.Printf("completed result of %#v is %#v", result, completedResult)
if err != nil {
return nil, err
}
Expand Down Expand Up @@ -1342,12 +1352,17 @@ func (executor *Executor) completeValue(reqCtx *RequestContext, objectType *Obje
Field: field,
}
}
return nil, nil
}

func (executor *Executor) resolveFieldOnObject(reqCtx *RequestContext, objectType *ObjectTypeDefinition, object interface{}, fieldType ASTNode, firstField *Field) (interface{}, error) {
doneCh := reqCtx.NetContext.Done()
select {
case <-doneCh:
return nil, ContextDoneErr
default:
}

resolverName := objectType.Name.Value + "/" + firstField.Name.Value
resolverName := fmt.Sprintf("%s/%s", objectType.Name.Value, firstField.Name.Value)
if resolver, ok := executor.Resolvers[resolverName]; ok {
var resolveFn ResolveFn
var beforeFn BeforeFn
Expand Down Expand Up @@ -1378,13 +1393,14 @@ func (executor *Executor) resolveFieldOnObject(reqCtx *RequestContext, objectTyp

// Execute the before function if it is defined
resolveParams := &ResolveParams{
Executor: executor,
Schema: executor.Schema.Document,
Request: reqCtx.Document,
Context: reqCtx.AppContext,
Source: object,
Args: args,
Field: firstField,
RequestContext: reqCtx.NetContext,
Executor: executor,
Schema: executor.Schema.Document,
Request: reqCtx.Document,
Context: reqCtx.AppContext,
Source: object,
Args: args,
Field: firstField,
}

if beforeFn != nil {
Expand Down Expand Up @@ -1438,6 +1454,13 @@ func (executor *Executor) resolveFieldOnObject(reqCtx *RequestContext, objectTyp
return result, nil
}

// Check again to see if the context is finished before we bother doing more work.
select {
case <-doneCh:
return nil, ContextDoneErr
default:
}

sourceVal := reflect.ValueOf(object)
sourceValType := sourceVal.Type()
sourceValKind := sourceValType.Kind()
Expand Down
24 changes: 12 additions & 12 deletions executor_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -10,14 +10,14 @@ import (
)

type Author struct {
ID int `json:"id"`
Name string `json:"name"`
IsPublished string `json:"isPublished"`
Author *Author `json:"author"`
Title string `json:"title"`
Body string `json:"body"`
keywords []interface{} `json:"keywords"`
RecentArticle *Article `json:"recentArticle"`
ID int `json:"id"`
Name string `json:"name"`
IsPublished string `json:"isPublished"`
Author *Author `json:"author"`
Title string `json:"title"`
Body string `json:"body"`
keywords []interface{}
RecentArticle *Article `json:"recentArticle"`
}

type Image struct {
Expand Down Expand Up @@ -3392,9 +3392,9 @@ func TestExecutor(t *testing.T) {
"deserializedValue": nil,
},
"errors": []map[string]interface{}{
map[string]interface{}{
{
"locations": []map[string]interface{}{
map[string]interface{}{
{
"line": 3,
"column": 13,
},
Expand Down Expand Up @@ -3501,9 +3501,9 @@ func TestExecutor(t *testing.T) {
"deserializedValue": nil,
},
"errors": []map[string]interface{}{
map[string]interface{}{
{
"locations": []map[string]interface{}{
map[string]interface{}{
{
"line": 3,
"column": 11,
},
Expand Down