Redirects stdout in the Gunicorn process to a log file

Gunicorn is currently running using a subprocess. When the stdout log information exists in the process, it is printed to the screen. This will greatly affect the user experience. So we need to redirect the stdout information to a log file to avoid printing logs in the console.

mindinsight/backend/run.py

@@ -228,18 +228,8 @@ class GunicornLogger(Logger):
         """Get log format."""
         return time.strftime('[%Y-%m-%d-%H:%M:%S %z]')
 
-    def rewrite_stdout(self, message):
-        if message.strip():
-            self.error_log.info(message)
-
-    def rewrite_stderr(self, message):
-        if message.strip():
-            self.error_log.error(message)
-
     def setup(self, cfg):
         """Rewrite the setup method of Logger, and we don't need to do anything"""
-        sys.stdout.write = self.rewrite_stdout
-        sys.stderr.write = self.rewrite_stderr
 
 
 def _get_all_ip_addresses(host):
@@ -263,8 +253,6 @@ def _get_all_ip_addresses(host):
 
 def start():
     """Start web service."""
-    errorlog_abspath = _get_error_log_path()
-
     gunicorn_conf_file = os.path.join(WEB_CONFIG_DIR, "gunicorn_conf.py")
     cmd = "gunicorn " \
           "-b {host}:{port} {app_module} " \
@@ -279,9 +267,12 @@ def start():
                 log_format=settings.GUNICORN_ACCESS_FORMAT
                 )
 
-    log_size = _get_file_size(errorlog_abspath)
+    error_log_abspath = _get_error_log_path()
+    log_size = _get_file_size(error_log_abspath)
 
-    console = setup_logger('mindinsight', 'console', console=True, logfile=False, formatter='%(message)s')
+    # Init the logger file
+    setup_logger('gunicorn', 'error')
+    log_handler = open(error_log_abspath, 'a+')
 
     # start server
     process = subprocess.Popen(
@@ -289,7 +280,7 @@ def start():
         shell=False,
         # Change stdout to DEVNULL to prevent broken pipe error when creating new processes.
         stdin=subprocess.DEVNULL,
-        stdout=None,
+        stdout=log_handler,
         stderr=subprocess.STDOUT
     )
 
@@ -297,11 +288,12 @@ def start():
     time.sleep(1)
 
     # check if gunicorn application is running
+    console = setup_logger('mindinsight', 'console', console=True, logfile=False, formatter='%(message)s')
     if process.poll() is not None:
-        console.error("Start MindInsight failed. See log for details.")
+        console.error("Start MindInsight failed. See log for details, log path: %s.", error_log_abspath)
         sys.exit(1)
     else:
-        state_result = _check_server_start_stat(errorlog_abspath, log_size)
+        state_result = _check_server_start_stat(error_log_abspath, log_size)
         # print gunicorn start state to stdout
         label = 'Web address:'
         for ip in _get_all_ip_addresses(settings.HOST):