Add app-local caching and stop using memcache; reduce overall datastore access.

lib/auth.py

@@ -17,7 +17,6 @@ import hmac
 import random
 import string
 
-from google.appengine.api import memcache
 from google.appengine.ext import db
 
 
@@ -32,11 +31,11 @@ class AuthKey(db.Model):
 
 _KEY_CHARS = string.ascii_letters + string.digits
 _KEY_LENGTH = 64
+_AUTH_KEY = []
 
 def GetAuthKey():
-  auth_key = memcache.get('auth_key')
-  if auth_key:
-    return auth_key
+  if _AUTH_KEY:
+    return _AUTH_KEY[0]
 
   for key in AuthKey.all().filter('live =', True):
     auth_key = key.auth_key
@@ -45,7 +44,7 @@ def GetAuthKey():
     auth_key = ''.join(random.choice(_KEY_CHARS) for _ in xrange(_KEY_LENGTH))
     AuthKey(auth_key=auth_key).put()
 
-  memcache.set('auth_key', auth_key)
+  _AUTH_KEY.append(auth_key)
   return auth_key
 
 

lib/models.py

@@ -112,6 +112,8 @@ class Subject(db.Model):
 
   next_message_id = db.IntegerProperty(required=True, default=1)
 
+  _cache = {}
+
   @classmethod
   def _UpdateHashWithString(cls, hashobj, string):
     string = string.encode('utf8')
@@ -138,12 +140,20 @@ class Subject(db.Model):
     else:
       writable_only_by = None
 
-    return cls.get_or_insert(
-        cls._KeyName(subject),
+    key_name = cls._KeyName(subject)
+    obj = cls._cache.get(key_name)
+    if obj:
+      return obj
+
+    obj = cls.get_or_insert(
+        key_name,
         name=subject['name'],
         readable_only_by=readable_only_by,
         writable_only_by=writable_only_by)
 
+    cls._cache[key_name] = obj
+    return obj
+
   @db.transactional()
   def GetRecentMessages(self, num_messages):
     query = (