A simple way to log all of indexes used by the application

hook.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# Copyright 2011 Sahid Orentino Ferdjaoui

import logging
import hashlib

from google.appengine.api import memcache
from google.appengine.api import apiproxy_stub_map
from google.appengine.ext import db
from google.appengine.datastore import datastore_index

"""A simple way to log all of indexes used by the application.
Just add this middleware in your django settings.
  MIDDLEWARE_CLASSES = (
  ...
  'middleware.hook.IndexesMiddleware',
  ...
)
"""

LOCK_KEY="<l>"
LOCK_TIME=3600

class _hook_indexes_stats(db.Model):
    index = db.StringProperty(required=True, multiline=True)
    name = db.StringProperty(required=True)
    created = db.DateTimeProperty(auto_now_add=True)
    updated = db.DateTimeProperty(auto_now_add=True, auto_now=True)

class IndexesMiddleware (object):
    """Store indexes used by the application.

    Install:
      Just add this middleware in your django settings.
      MIDDLEWARE_CLASSES = (
        ...
        'middleware.hook.IndexesMiddleware',
        ...
      )
    """
    def process_request (self, request):
        def log_api_call(service, call, request, response):
            if call == 'RunQuery':
                required, kind, ancestor, props, eq_filters = \
                          datastore_index.CompositeIndexForQuery(request)

                index = datastore_index.IndexYamlForQuery(kind, ancestor, props)
                index_key = hashlib.sha1(index).hexdigest()

                if not memcache.get(index_key):
                    if memcache.add(index_key, LOCK_KEY, LOCK_TIME):
                        logging.info("indexes: \n%s", index)
                        _hook_indexes_stats(
                            key_name=index_key,
                            name=kind,
                            index=index).put()
        
        apiproxy_stub_map.apiproxy.GetPreCallHooks().Append(
            'log_api_call', log_api_call, 'datastore_v3')