Added Unix socket connection support to the redis transport

cf. https://github.com/celery/celery/issues/1283
and https://github.com/piquadrat/celery-redis-unixsocket/issues/3

docs/userguide/connections.rst

@@ -70,6 +70,9 @@ All of these are valid URLs::
     # Using Redis
     redis://localhost:6379/
 
+    # Using Redis over a Unix socket
+    redis+socket:///tmp/redis.sock
+
     # Using virtual host '/foo'
     amqp://localhost//foo
 

kombu/connection.py

@@ -579,7 +579,8 @@ class Connection(object):
 
     def as_uri(self, include_password=False):
         """Convert connection parameters to URL form."""
-        if self.transport_cls in URI_PASSTHROUGH:
+        if (self.transport_cls in URI_PASSTHROUGH or
+                self.hostname.startswith('socket://')):
             return self.transport_cls + '+' + (self.hostname or 'localhost')
         quoteS = partial(quote, safe='')   # strict quote
         fields = self.info()

kombu/tests/transport/test_redis.py

@@ -477,6 +477,15 @@ class test_Channel(TestCase):
         with self.assertRaises(InconsistencyError):
             self.channel.get_table('celery')
 
+    @skip_if_not_module('redis')
+    def test_socket_connection(self):
+        connection = Connection('redis+socket:///tmp/redis.sock',
+                                transport=Transport)
+        connparams = connection.channel()._connparams()
+        self.assertEqual(connparams['connection_class'],
+                         redis.redis.UnixDomainSocketConnection)
+        self.assertEqual(connparams['path'], '/tmp/redis.sock')
+
 
 class test_Redis(TestCase):
 

kombu/transport/redis.py

@@ -623,12 +623,19 @@ class Channel(virtual.Channel):
             except ValueError:
                 raise ValueError(
                     'Database name must be int between 0 and limit - 1')
-        return {'host': conninfo.hostname or '127.0.0.1',
-                'port': conninfo.port or DEFAULT_PORT,
-                'db': database,
-                'password': conninfo.password,
-                'max_connections': self.max_connections,
-                'socket_timeout': self.socket_timeout}
+        connparams = {'host': conninfo.hostname or '127.0.0.1',
+                      'port': conninfo.port or DEFAULT_PORT,
+                      'db': database,
+                      'password': conninfo.password,
+                      'max_connections': self.max_connections,
+                      'socket_timeout': self.socket_timeout}
+        if conninfo.hostname.split('://')[0] == 'socket':
+            connparams.update({
+                'connection_class': redis.UnixDomainSocketConnection,
+                'path': conninfo.hostname.split('://')[1]})
+            connparams.pop('host', None)
+            connparams.pop('port', None)
+        return connparams
 
     def _create_client(self):
         return self.Client(connection_pool=self.pool)