diff --git a/terminal_appengine.go b/terminal_appengine.go
index 632ecbe..e011a86 100644
--- a/terminal_appengine.go
+++ b/terminal_appengine.go
@@ -2,6 +2,8 @@
 
 package logrus
 
+import "io"
+
 // IsTerminal returns true if stderr's file descriptor is a terminal.
 func IsTerminal(f io.Writer) bool {
 	return true