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-rw-r--r--main/log.py71
1 files changed, 71 insertions, 0 deletions
diff --git a/main/log.py b/main/log.py
new file mode 100644
index 0000000..6363487
--- /dev/null
+++ b/main/log.py
@@ -0,0 +1,71 @@
+# Derived from Django snippets: http://djangosnippets.org/snippets/2242/
+from collections import OrderedDict
+from datetime import datetime, timedelta
+from hashlib import md5
+import traceback
+from pytz import utc
+
+
+class LimitedSizeDict(OrderedDict):
+ def __init__(self, *args, **kwargs):
+ self.size_limit = kwargs.pop('size', None)
+ if self.size_limit == 0:
+ self.size_limit = None
+ if self.size_limit and self.size_limit < 0:
+ raise Exception('Invalid size specified')
+ super(LimitedSizeDict, self).__init__(*args, **kwargs)
+ self.check_item_limits()
+
+ def __setitem__(self, key, value):
+ # delete and add to ensure it ends up at the end of the linked list
+ if key in self:
+ super(LimitedSizeDict, self).__delitem__(key)
+ super(LimitedSizeDict, self).__setitem__(key, value)
+ self.check_item_limits()
+
+ def check_item_limits(self):
+ if self.size_limit is None:
+ return
+ while len(self) > self.size_limit:
+ self.popitem(last=False)
+
+
+class RateLimitFilter(object):
+ def __init__(self, name='', rate=10, prefix='error_rate', max_keys=100):
+ # delayed import otherwise we have a circular dep when setting up
+ # the logging config: settings -> logging -> cache -> settings
+ self.cache_module = __import__('django.core.cache', fromlist=['cache'])
+ self.errors = LimitedSizeDict(size=max_keys)
+ self.rate = rate
+ self.prefix = prefix
+
+ def filter(self, record):
+ if self.rate == 0:
+ # rate == 0 means totally unfiltered
+ return True
+
+ trace = '\n'.join(traceback.format_exception(*record.exc_info))
+ key = md5(trace).hexdigest()
+ duplicate = False
+ cache = self.cache_module.cache
+
+ # Test if the cache works
+ try:
+ cache.set(self.prefix, 1, 300)
+ use_cache = (cache.get(self.prefix) == 1)
+ except:
+ use_cache = False
+
+ if use_cache:
+ cache_key = '%s_%s' % (self.prefix, key)
+ duplicate = (cache.get(cache_key) == 1)
+ cache.set(cache_key, 1, self.rate)
+ else:
+ now = datetime.utcnow().replace(tzinfo=utc)
+ min_date = now - timedelta(seconds=self.rate)
+ duplicate = (key in self.errors and self.errors[key] >= min_date)
+ self.errors[key] = now
+
+ return not duplicate
+
+# vim: set ts=4 sw=4 et: