From dc3f5f31fe980c1cc54d47513d83fa8d9e94fd87 Mon Sep 17 00:00:00 2001
From: garenchan <1412950785@qq.com>
Date: Thu, 20 Sep 2018 11:36:37 +0800
Subject: [PATCH] Specify that the encoding of file handler is utf-8. Fix issue
 #2503.

---
 tornado/log.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tornado/log.py b/tornado/log.py
index 5948d43ba..1bb6f9571 100644
--- a/tornado/log.py
+++ b/tornado/log.py
@@ -220,13 +220,15 @@ def enable_pretty_logging(options: Any=None,
             channel = logging.handlers.RotatingFileHandler(
                 filename=options.log_file_prefix,
                 maxBytes=options.log_file_max_size,
-                backupCount=options.log_file_num_backups)  # type: logging.Handler
+                backupCount=options.log_file_num_backups,
+                encoding="utf-8")  # type: logging.Handler
         elif rotate_mode == 'time':
             channel = logging.handlers.TimedRotatingFileHandler(
                 filename=options.log_file_prefix,
                 when=options.log_rotate_when,
                 interval=options.log_rotate_interval,
-                backupCount=options.log_file_num_backups)
+                backupCount=options.log_file_num_backups,
+                encoding="utf-8")
         else:
             error_message = 'The value of log_rotate_mode option should be ' +\
                             '"size" or "time", not "%s".' % rotate_mode
-- 
2.47.2