+#!/usr/bin/python
+#-*- coding: utf-8 -*-
+#
+# S.Çağlar Onur <caglar@cs.princeton.edu>
+
+from PLC.Config import Config
+from PLC.Faults import PLCPermissionDenied
+
+from datetime import datetime, timedelta
+
+from pyaspects.meta import MetaAspect
+
+import memcache
+
+class BaseRateLimit(object):
+
+ def __init__(self):
+ self.config = Config("/etc/planetlab/plc_config")
+
+ # FIXME: change with Config values
+ self.prefix = "ratelimit"
+ self.minutes = 5 # The time period
+ self.requests = 50 # Number of allowed requests in that time period
+ self.expire_after = (self.minutes + 1) * 60
+
+ def before(self, wobj, data, *args, **kwargs):
+ # ratelimit_128.112.139.115_201011091532 = 1
+ # ratelimit_128.112.139.115_201011091533 = 14
+ # ratelimit_128.112.139.115_201011091534 = 11
+ # Now, on every request we work out the keys for the past five minutes and use get_multi to retrieve them.
+ # If the sum of those counters exceeds the maximum allowed for that time period, we block the request.
+
+ api_method_name = wobj.name
+ api_method_source = wobj.source
+
+ if api_method_source == None or api_method_source[0] == self.config.PLC_API_IP:
+ return
+
+ mc = memcache.Client(["%s:11211" % self.config.PLC_API_HOST])
+ now = datetime.now()
+ current_key = "%s_%s_%s" % (self.prefix, api_method_source[0], now.strftime("%Y%m%d%H%M"))
+
+ keys_to_check = ["%s_%s_%s" % (self.prefix, api_method_source[0], (now - timedelta(minutes = minute)).strftime("%Y%m%d%H%M")) for minute in range(self.minutes + 1)]
+
+ try:
+ mc.incr(current_key)
+ except ValueError:
+ mc.set(current_key, 1, time=self.expire_after)
+
+ result = mc.get_multi(keys_to_check)
+ total_requests = 0
+ for i in result:
+ total_requests += result[i]
+
+ if total_requests > self.requests:
+ log = open("/var/log/plc_api_ratelimit.log", "a")
+ date = datetime.now().strftime("%d/%m/%y %H:%M")
+ log.write("%s - %s\n" % (date, api_method_source[0]))
+ log.flush()
+ raise PLCPermissionDenied, "Maximum allowed number of API calls exceeded"
+
+ def after(self, wobj, data, *args, **kwargs):
+ return
+
+class RateLimitAspect_class(BaseRateLimit):
+ __metaclass__ = MetaAspect
+ name = "ratelimitaspect_class"
+
+ def __init__(self):
+ BaseRateLimit.__init__(self)
+
+ def before(self, wobj, data, *args, **kwargs):
+ BaseRateLimit.before(self, wobj, data, *args, **kwargs)
+
+ def after(self, wobj, data, *args, **kwargs):
+ BaseRateLimit.after(self, wobj, data, *args, **kwargs)
+
+RateLimitAspect = RateLimitAspect_class