sharded-counters/main.py

   1 #!/usr/bin/env python
   2 #
   3 # Copyright 2008 Google Inc.
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16 #
  17
  18 """A simple application that demonstrates sharding counters
  19    to achieve higher throughput.
  20
  21 Demonstrates:
  22    * Sharding - Sharding a counter into N random pieces
  23    * Memcache - Using memcache to cache the total counter value in generalcounter.
  24 """
  25
  26 import os
  27 import wsgiref.handlers
  28 from google.appengine.ext import webapp
  29 from google.appengine.ext.webapp import template
  30 import generalcounter
  31 import simplecounter
  32
  33 class CounterHandler(webapp.RequestHandler):
  34   """Handles displaying the values of the counters
  35   and requests to increment either counter.
  36   """
  37
  38   def get(self):
  39     template_values = {
  40       'simpletotal': simplecounter.get_count(),
  41       'generaltotal': generalcounter.get_count('FOO')
  42     }
  43     template_file = os.path.join(os.path.dirname(__file__), 'counter.html')
  44     self.response.out.write(template.render(template_file, template_values))
  45
  46   def post(self):
  47     counter = self.request.get('counter')
  48     if counter == 'simple':
  49       simplecounter.increment()
  50     else:
  51       generalcounter.increment('FOO')
  52     self.redirect("/")
  53
  54
  55 def main():
  56   application = webapp.WSGIApplication(
  57   [
  58     ('/', CounterHandler),
  59   ], debug=True)
  60   wsgiref.handlers.CGIHandler().run(application)
  61
  62
  63 if __name__ == '__main__':
  64   main()
  65
  66