use goField directive for getters generation

plugin/modelgen/models.go

@@ -23,6 +23,11 @@ type FieldMutateHook = func(td *ast.Definition, fd *ast.FieldDefinition, f *Fiel
 
 // defaultFieldMutateHook is the default hook for the Plugin which applies the GoTagFieldHook.
 func defaultFieldMutateHook(td *ast.Definition, fd *ast.FieldDefinition, f *Field) (*Field, error) {
+	var err error
+	f, err = GoFieldHook(td, fd, f)
+	if err != nil {
+		return f, err
+	}
 	return GoTagFieldHook(td, fd, f)
 }
 
@@ -412,6 +417,20 @@ func GoTagFieldHook(td *ast.Definition, fd *ast.FieldDefinition, f *Field) (*Fie
 	return f, nil
 }
 
+// GoFieldHook applies the goField directive to the generated Field f.
+func GoFieldHook(td *ast.Definition, fd *ast.FieldDefinition, f *Field) (*Field, error) {
+	args := make([]string, 0)
+	_ = args
+	for _, goField := range fd.Directives.ForNames("goField") {
+		if arg := goField.Arguments.ForName("name"); arg != nil {
+			if k, err := arg.Value.Value(nil); err == nil {
+				f.GoName = k.(string)
+			}
+		}
+	}
+	return f, nil
+}
+
 func isStruct(t types.Type) bool {
 	_, is := t.Underlying().(*types.Struct)
 	return is

plugin/modelgen/testdata/schema.graphql

@@ -3,6 +3,11 @@ directive @goTag(
     value: String
 ) on INPUT_FIELD_DEFINITION | FIELD_DEFINITION
 
+directive @goField(
+	forceResolver: Boolean
+	name: String
+) on INPUT_FIELD_DEFINITION | FIELD_DEFINITION | INTERFACE
+
 type Query {
     thisShoudlntGetGenerated: Boolean
 }
@@ -178,4 +183,13 @@ interface ArrayOfA {
 type ImplArrayOfA implements ArrayOfA {
     trickyField: [CDImplemented!]!
     trickyFieldPointer: [CDImplemented]
+}
+
+interface X {
+    Id: String! @goField(name: "Id")
+}
+
+type Xer implements X {
+    Id: String! @goField(name: "Id")
+    Name: String!
 }