Add resolver middleware Add opentracing support

.gometalinter.json

@@ -1,5 +1,6 @@
 {
   "sort": ["path"],
+  "Deadline": "2m",
   "Linters": {
     "errcheck": {
       "Command":           "errcheck -abspath -ignore '[rR]ead|[wW]rite|Close'",

codegen/object.go

@@ -89,8 +89,8 @@ func (f *Field) CallArgs() string {
 		}
 	}
 
-	for i := range f.Args {
-		args = append(args, "arg"+strconv.Itoa(i))
+	for _, arg := range f.Args {
+		args = append(args, "args["+strconv.Quote(arg.GQLName)+"].("+arg.Signature()+")")
 	}
 
 	return strings.Join(args, ", ")

codegen/templates/args.gotpl

@@ -1,3 +1,4 @@
+	{{- if . }}args := map[string]interface{}{} {{end}}
 	{{- range $i, $arg := . }}
 		var arg{{$i}} {{$arg.Signature }}
 		if tmp, ok := field.Args[{{$arg.GQLName|quote}}]; ok {
@@ -25,4 +26,5 @@
 			}
 		}
 		{{end }}
+		args[{{$arg.GQLName|quote}}] = arg{{$i}}
 	{{- end -}}

codegen/templates/field.gotpl

@@ -48,12 +48,22 @@
 					}
 				{{- end }}
 			{{- else }}
-				rctx := graphql.WithResolverContext(ctx, &graphql.ResolverContext{Field: field})
-				res, err := ec.resolvers.{{ $object.GQLType }}_{{ $field.GQLName }}({{ $field.CallArgs }})
+				rctx := graphql.WithResolverContext(ctx, &graphql.ResolverContext{
+					Object: {{$object.GQLType|quote}},
+					Args: {{if $field.Args }}args{{else}}nil{{end}},
+					Field: field,
+				})
+				resTmp, err := ec.Middleware(rctx, func(rctx context.Context) (interface{}, error) {
+					return ec.resolvers.{{ $object.GQLType }}_{{ $field.GQLName }}({{ $field.CallArgs }})
+				})
 				if err != nil {
 					ec.Error(err)
 					return graphql.Null
 				}
+				if resTmp == nil {
+					return graphql.Null
+				}
+				res := resTmp.({{$field.Signature}})
 			{{- end }}
 			{{ $field.WriteJson }}
 		{{- if $field.IsConcurrent }}