go-colorable does not work in app engine

mode.go

@@ -9,7 +9,6 @@ import (
 	"os"
 
 	"github.com/gin-gonic/gin/binding"
-	"github.com/mattn/go-colorable"
 )
 
 const ENV_GIN_MODE = "GIN_MODE"
@@ -25,7 +24,18 @@ const (
 	testCode    = iota
 )
 
-var DefaultWriter io.Writer = colorable.NewColorableStdout()
+// DefaultWriter is the default io.Writer used the Gin for debug output and
+// middleware output like Logger() or Recovery().
+// Note that both Logger and Recovery provides custom ways to configure their
+// output io.Writer.
+// To support coloring in Windows use:
+// ```
+// import "github.com/mattn/go-colorable"
+// gin.DefaultWriter = colorable.NewColorableStdout()
+// ```
+var DefaultWriter io.Writer = os.Stdout
+var DefaultErrorWriter io.Writer = os.Stderr
+
 var ginMode int = debugCode
 var modeName string = DebugMode