Ticket #11565: error_emails_rate_limit.patch

django/core/handlers/base.py

@@ +1 @@
+try:
+    from hashlib import md5
+except ImportError:
+    from md5 import md5
 import sys
 
+from django.core.cache import cache                               
 from django import http
 from django.core import signals
 from django.utils.encoding import force_unicode
@@ -154 +159 @@
             return debug.technical_500_response(request, *exc_info)
 
         # When DEBUG is False, send an error message to the admins.
-        subject = 'Error (%s IP): %s' % ((request.META.get('REMOTE_ADDR') in settings.INTERNAL_IPS and 'internal' or 'EXTERNAL'), request.path)
+        # To ensure we only send one email per ERROR_EMAIL_RATE_LIMIT time period                                                              
+        # we take an md5 of the traceback and store it in the cache with a timeout.                                                            
+        # If the value exists in the cache then we skip sending an email.                                                                      
+        tb = self._get_traceback(exc_info)                                                                                                     
+        key = "django_error_md5_%s" % (md5(unicode(tb).encode("utf8")).hexdigest(), )
+
+        # The worst case is for the cache to have failed and to be raising exceptions so we mask them all.
         try:
-            request_repr = repr(request)
+            cache_hit = cache.get(key) is not None
         except:
-            request_repr = "Request repr() unavailable"
-        message = "%s\n\n%s" % (self._get_traceback(exc_info), request_repr)
-        mail_admins(subject, message, fail_silently=True)
+            cache_hit = False
+
+        if not cache_hit:
+            subject = 'Error (%s IP): %s' % ((request.META.get('REMOTE_ADDR') in settings.INTERNAL_IPS and 'internal' or 'EXTERNAL'), request.path)
+            try:
+                request_repr = repr(request)
+            except:
+                request_repr = "Request repr() unavailable"
+            message = "%s\n\n%s" % (tb, request_repr)
+            mail_admins(subject, message, fail_silently=True)
+
+            # If the error emails are being rate limited set a cache value to prevent the same email being send again
+            if hasattr(settings, "ERROR_EMAIL_RATE_LIMIT") and settings.ERROR_EMAIL_RATE_LIMIT > 0:
+                try:
+                    cache.set(key, "Error Occurred!", settings.ERROR_EMAIL_RATE_LIMIT*60)
+                except:
+                    pass
+
         # Return an HttpResponse that displays a friendly error message.
         callback, param_dict = resolver.resolve500()
         return callback(request, **param_dict)

docs/ref/settings.txt

@@ -447 +447 @@
 
 Whether to use a TLS (secure) connection when talking to the SMTP server.
 
+.. setting:: ERROR_EMAIL_RATE_LIMIT
+
+ERROR_EMAIL_RATE_LIMIT
+----------------------
+
+Default: ``0``
+
+How often to send emails to the admins regarding errors in minutes. If set to 0 an email is send for every exception, if greater than 0 then an email is send once every ``ERROR_EMAIL_RATE_LIMIT`` minutes for each distinct traceback.
+
+This settings requires a configured cache backend to function correctly.
+
 .. setting:: FILE_CHARSET
 
 FILE_CHARSET