Prefix based router support

nydus/db/base.py

@@ -82,6 +82,7 @@ def _execute(self, attr, args, kwargs):
 
         results = []
         for conn in connections:
+            print conn
             for retry in xrange(self.max_connection_retries):
                 try:
                     results.append(getattr(conn, attr)(*args, **kwargs))

nydus/db/routers/__init__.py

@@ -8,3 +8,4 @@
 
 from .base import BaseRouter, RoundRobinRouter
 
+from .prefix_partition import PrefixPartitionRouter

nydus/db/routers/prefix_partition.py

@@ -0,0 +1,43 @@
+from nydus.db.routers import BaseRouter
+
+class PrefixPartitionRouter(BaseRouter):
+    '''
+    Routes based on the configured prefixes
+
+    Example config:
+
+    'redis': {
+        'engine': 'nydus.db.backends.redis.Redis',
+        'router': 'django_redis.nydus_router.PrefixPartitionRouter',
+        'hosts': {
+            0: {'db': 0, 'host': 'default.redis.goteam.be', 'port': 6379},
+            'user:loves:': {'db': 1, 'host': 'default.redis.goteam.be', 'port': 6379},
+            'loves:': {'db': 2, 'host': 'default.redis.goteam.be', 'port': 6379},
+            'hash:entity:': {'db': 0, 'host': 'entities.redis.goteam.be', 'port': 6379},
+        }
+    }
+
+    We route to one and only one redis.
+    Use a seperate config if you want hashing based partitioning.
+    '''
+
+    def _route(self, cluster, attr, key, *args, **kwargs):
+        """
+        Perform routing and return db_nums
+        """
+        assert 'default' in cluster.hosts, 'The prefix router requires a default key to route to'
+        hosts = None
+        if key:
+            for host in cluster.hosts:
+                if key.startswith(str(host)):
+                    hosts = [host]
+            if not hosts:
+                hosts = ['default']
+        elif func == 'pipeline':
+            raise ValueError('Pipelines requires a key for proper routing')
+
+        if not hosts:
+            raise ValueError, 'I didnt expect this while writing the code so lets fail'
+
+        return hosts
+

nydus/db/routers/redis.py

@@ -6,8 +6,8 @@
 :license: Apache License 2.0, see LICENSE for more details.
 """
 
-from nydus.db.routers import RoundRobinRouter
+from nydus.db.routers import RoundRobinRouter, PrefixPartitionRouter
 from nydus.db.routers.keyvalue import ConsistentHashingRouter, PartitionRouter
 
-__all__ = ('ConsistentHashingRouter', 'PartitionRouter', 'RoundRobinRouter')
+__all__ = ('PrefixPartitionRouter', 'ConsistentHashingRouter', 'PartitionRouter', 'RoundRobinRouter')
 

tests/nydus/db/routers/tests.py

@@ -14,6 +14,37 @@
 from nydus.db.routers.keyvalue import ConsistentHashingRouter, PartitionRouter
 
 
+class PrefixPartitionTest(TestCase):
+    def test_partitions(self):
+        '''
+        Verify if we write ton one and only one redis database
+        '''
+        from nydus.db import create_cluster
+        import mock
+        engine = 'nydus.db.backends.redis.Redis'
+        router = 'nydus.db.routers.redis.PrefixPartitionRouter'
+        nydus_config = dict(engine=engine, router=router, hosts={
+            'default': {'db': 0, 'host': 'localhost', 'port': 6379},
+            'user:loves:': {'db': 1, 'host': 'localhost', 'port': 6379}
+        })
+        redis = create_cluster(nydus_config)
+
+        keys = [
+            ('user:loves:test', 1), 
+            ('default_test',0),
+            ('hash:entity:test', 0)
+        ]
+
+        for key, redis_db in keys:
+            with mock.patch('redis.client.StrictRedis.execute_command') as fake_set:
+                result = redis.set(key, '1')
+                args, kwargs = fake_set.call_args
+                instance, cmd, key, key_value = args 
+                connection_kwargs = instance.connection_pool.connection_kwargs
+                db = connection_kwargs['db']
+                self.assertEqual(db, redis_db)
+
+
 class DummyConnection(BaseConnection):
     def __init__(self, i):
         self.host = 'dummyhost'