much better error handling

app.py

@@ -38,6 +38,10 @@ def __init__(self, database_name=None):
             static_path=os.path.join(os.path.dirname(__file__), "static"),
             cookie_secret=settings.COOKIE_SECRET,
             debug=options.debug,
+            email_backend=options.debug and \
+                 'tornado_utils.send_mail.backends.console.EmailBackend' \
+              or 'tornado_utils.send_mail.backends.pickle.EmailBackend',
+            admin_emails=settings.ADMIN_EMAILS,
             ui_modules=ui_modules_map,
             twitter_consumer_key=settings.TWITTER_CONSUMER_KEY,
             twitter_consumer_secret=settings.TWITTER_CONSUMER_SECRET,

handlers.py

@@ -9,6 +9,7 @@
 import tornado.gen
 from tornado.web import HTTPError
 from tornado_utils.routes import route
+from tornado_utils.send_mail import send_email
 from tornado.escape import json_decode, json_encode
 from pymongo.objectid import InvalidId, ObjectId
 import utils
@@ -118,6 +119,73 @@ def render(self, template, **options):
         options['background_image'] = background_image
         return tornado.web.RequestHandler.render(self, template, **options)
 
+    def write_error(self, status_code, **kwargs):
+        if status_code >= 500 and not self.application.settings['debug']:
+            if self.application.settings['admin_emails']:
+                try:
+                    self._email_exception(status_code, *kwargs['exc_info'])
+                except:
+                    logging.error("Failing to email exception", exc_info=True)
+            else:
+                logging.warn("No ADMIN_EMAILS set up in settings to "
+                             "email exception")
+        if self.application.settings['debug']:
+            super(BaseHandler, self).write_error(status_code, **kwargs)
+        else:
+            options = dict(
+              status_code=status_code,
+              err_type=kwargs['exc_info'][0],
+              err_value=kwargs['exc_info'][1],
+              err_traceback=kwargs['exc_info'][2],
+            )
+            self.render("error.html", **options)
+
+    def _email_exception(self, status_code, err_type, err_val, err_traceback):
+        import traceback
+        from cStringIO import StringIO
+        from pprint import pprint
+        out = StringIO()
+        subject = "%r on %s" % (err_val, self.request.path)
+        out.write("TRACEBACK:\n")
+        traceback.print_exception(err_type, err_val, err_traceback, 500, out)
+        traceback_formatted = out.getvalue()
+        #print traceback_formatted
+        out.write("\nREQUEST ARGUMENTS:\n")
+        arguments = self.request.arguments
+        if arguments.get('password') and arguments['password'][0]:
+            password = arguments['password'][0]
+            arguments['password'] = password[:2] + '*' * (len(password) -2)
+        pprint(arguments, out)
+        out.write("\nCOOKIES:\n")
+        for cookie in self.cookies:
+            out.write("\t%s: " % cookie)
+            out.write("%r\n" % self.get_secure_cookie(cookie))
+
+        out.write("\nREQUEST:\n")
+        for key in ('full_url', 'protocol', 'query', 'remote_ip',
+                    'request_time', 'uri', 'version'):
+            out.write("  %s: " % key)
+            value = getattr(self.request, key)
+            if callable(value):
+                try:
+                    value = value()
+                except:
+                    pass
+            out.write("%r\n" % value)
+
+        out.write("\nHEADERS:\n")
+        pprint(dict(self.request.headers), out)
+        try:
+            send_email(self.application.settings['email_backend'],
+                   subject,
+                   out.getvalue(),
+                   self.application.settings['admin_emails'][0],
+                   self.application.settings['admin_emails'],
+                   )
+        except:
+            logging.error("Failed to send email",
+                          exc_info=True)
+
 
 @route('/')
 class HomeHandler(BaseHandler):

settings.py

@@ -10,6 +10,10 @@
 
 DATABASE_NAME = 'toocool'
 
+# complete this in your local_settings.py to get emails sent on errors
+ADMIN_EMAILS = (
+)
+
 try:
     from local_settings import *
 except ImportError:

templates/error.html

@@ -0,0 +1,75 @@
+<html>
+<head>
+<title>Arse!! An error happened! ({{ status_code }})</title>
+<link href='http://fonts.googleapis.com/css?family=VT323' rel='stylesheet' type='text/css'>
+<style>
+body {
+    background:#0000aa;
+    color:#ffffff;
+    font-family:'VT323', courier;
+    font-size:15pt;
+    text-align:center;
+    margin:100px;
+}
+
+blink {
+    color:yellow;
+}
+
+.neg {
+    background:#fff;
+    color:#0000aa;
+    padding:2px 8px;
+    font-weight:bold;
+}
+
+p {
+    margin:30px 100px;
+    text-align:left;
+}
+
+a,a:hover {
+    color:inherit;
+    font:inherit;
+}
+
+.menu {
+    text-align:center;
+    margin-top:50px;
+}
+</style>
+</head>
+<body>
+<span class="neg">ERROR {{ status_code }} - NOT COOL!</span>
+
+<p>
+{% if status_code == 500 %}
+The page you requested caused an unexpected server error. In other words,
+it's not your fault. However, try restarting your computer and it will
+probably solve it.
+{% else %}
+  {% if status_code == 404 %}
+  The page is missing or never was written. You can wait and
+  see if it becomes available again,<br>or you can restart your computer.
+  {% else %}
+    {{ err_value }}<br>That's not good. Most likely this problem will
+    solve itself if you just restart your computer.
+
+  {% end %}
+
+{% end %}
+</p>
+
+
+
+
+<p>
+* Send us an e-mail to notify this and try it later.<br>
+
+* Press CTRL+ALT+DEL to restart your computer. You will<br>
+ &nbsp; lose unsaved information in any programs that are running.
+</p>
+Press any link to continue <blink>_</blink>
+
+</body>
+</html>