log user-agent to console access logs

 * Taken from:
   https://groups.google.com/forum/#!topic/python-tornado/uomAkaY05cc

 * Update the standard access log to mimic Apache style.

 * Prefix application error logs with "[User-Agent: foo]".

Author: felliott

mfr/server/app.py

@@ -1,3 +1,4 @@
+import time
 import signal
 import asyncio
 import logging
@@ -19,6 +20,7 @@
 from mfr.version import __version__
 
 logger = logging.getLogger(__name__)
+access_logger = logging.getLogger('tornado.access')
 
 
 def sig_handler(sig, frame):
@@ -33,6 +35,16 @@ def stop_loop():
     io_loop.add_callback_from_signal(stop_loop)
 
 
+def almost_apache_style_log(handler):
+    '''without status code and body length'''
+    req = handler.request
+    access_logger.info('%s - - [%s +0800] "%s %s %s" - - "%s" "%s"' %
+                       (req.remote_ip, time.strftime("%d/%b/%Y:%X"), req.method,
+                        req.uri,
+                        req.version, getattr(req, 'referer', '-'),
+                        req.headers['User-Agent']))
+
+
 def make_app(debug):
     app = tornado.web.Application(
         [
@@ -45,6 +57,7 @@ def make_app(debug):
             (r'/status', StatusHandler),
         ],
         debug=debug,
+        log_function=almost_apache_style_log,
     )
     app.sentry_client = AsyncSentryClient(settings.SENTRY_DSN, release=__version__)
     return app

mfr/server/handlers/core.py

@@ -203,8 +203,10 @@ def log_exception(self, typ, value, tb):
                         list(value.args))
                 tornado.web.gen_log.warning(format, *args)
         else:
-            tornado.web.app_log.error("Uncaught exception %s\n", self._request_summary(),
-                                       exc_info=(typ, value, tb))
+            tornado.web.app_log.error("[User-Agent: %s] Uncaught exception %s\n",
+                                      self.request.headers.get('User-Agent', '*none found*'),
+                                      self._request_summary(),
+                                      exc_info=(typ, value, tb))
 
     def on_finish(self):
         if self.request.method not in self.ALLOWED_METHODS: