Implement basic email error reporting.

Here we send an email for each unique error every ten minutes.

(imported from commit adf5ee4bf52c9aef253a94b1c3647515d9b3e495)

humbug/ratelimit.py

@@ -0,0 +1,35 @@
+import traceback
+from hashlib import sha256
+from datetime import datetime, timedelta
+
+# Adapted http://djangosnippets.org/snippets/2242/ by user s29 (October 25, 2010)
+
+class RateLimitFilter(object):
+
+    last_error = 0
+
+    def filter(self, record):
+        from django.conf import settings
+        from django.core.cache import cache
+
+        # Track duplicate errors
+        duplicate = False
+        rate = getattr(settings, 'ERROR_RATE_LIMIT', 600)  # seconds
+        if rate > 0:
+            # Test if the cache works
+            try:
+                cache.set('RLF_TEST_KEY', 1, 1)
+                use_cache = cache.get('RLF_TEST_KEY') == 1
+            except:
+                use_cache = False
+
+            if use_cache:
+                duplicate = cache.get('ERROR_RATE') == 1
+                cache.set('ERROR_RATE', 1, rate)
+            else:
+                min_date = datetime.now() - timedelta(seconds=rate)
+                duplicate = (self.last_error >= min_date)
+                if not duplicate:
+                    self.last_error = datetime.now()
+
+        return not duplicate

humbug/settings.py

@@ -154,6 +154,7 @@ if deployed:
         'LOCATION': '127.0.0.1:11211',
         'TIMEOUT':  3600
     } }
+    error_filters = ['ratelimit']
 else:
     CACHES = { 'default': {
         'BACKEND':  'django.core.cache.backends.locmem.LocMemCache',
@@ -163,6 +164,9 @@ else:
             'MAX_ENTRIES': 100000
         }
     } }
+    error_filters = []
+
+ERROR_RATE_LIMIT=600
 
 LOGGING = {
     'version': 1,
@@ -172,6 +176,11 @@ LOGGING = {
             'format': '%(asctime)s %(levelname)-8s %(message)s'
         }
     },
+    'filters': {
+        'ratelimit': {
+            '()': 'humbug.ratelimit.RateLimitFilter',
+        }
+    },
     'handlers': {
         'console': {
             'level':     'DEBUG',
@@ -183,11 +192,16 @@ LOGGING = {
             'class':     'logging.FileHandler',
             'formatter': 'default',
             'filename':  'server.log'
-        }
+        },
+        'mail_admins': {
+            'level': 'ERROR',
+            'class': 'django.utils.log.AdminEmailHandler',
+            'filters': error_filters,
+        },
     },
     'loggers': {
         '': {
-            'handlers': ['console', 'file'],
+            'handlers': ['console', 'file', 'mail_admins'],
             'level':    'INFO'
         }
     }