From fa9f06b2aafb16f2bf404bf9da85c37aebc2786c Mon Sep 17 00:00:00 2001
From: "vn.py" <xiaoyou.chen@foxmail.com>
Date: Mon, 10 Jun 2019 14:54:41 +0800
Subject: [PATCH] [Mod] Close #1708

---
 vnpy/trader/engine.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vnpy/trader/engine.py b/vnpy/trader/engine.py
index 9b60bae0..9a65e90d 100644
--- a/vnpy/trader/engine.py
+++ b/vnpy/trader/engine.py
@@ -299,7 +299,7 @@ class LogEngine(BaseEngine):
         file_path = log_path.joinpath(filename)
 
         file_handler = logging.FileHandler(
-            file_path, mode="w", encoding="utf8"
+            file_path, mode="a", encoding="utf8"
         )
         file_handler.setLevel(self.level)
         file_handler.setFormatter(self.formatter)