From 31d7869842c516443accfc7702798913177bd428 Mon Sep 17 00:00:00 2001
From: Ask Solem <ask@celeryproject.org>
Date: Thu, 23 Aug 2012 15:56:45 +0100
Subject: [PATCH] Resolve amqp alias at runtime

---
 kombu/connection.py         |  5 +++--
 kombu/transport/__init__.py | 22 +++++++++-------------
 2 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/kombu/connection.py b/kombu/connection.py
index 448129012..c10a025e8 100644
--- a/kombu/connection.py
+++ b/kombu/connection.py
@@ -24,7 +24,7 @@
 # (Issue #112)
 from kombu import exceptions
 from .log import get_logger
-from .transport import AMQP_ALIAS, get_transport_cls
+from .transport import get_transport_cls, supports_librabbitmq
 from .utils import cached_property, retry_over_time
 from .utils.compat import OrderedDict, LifoQueue as _LifoQueue
 from .utils.url import parse_url
@@ -133,6 +133,8 @@ def __init__(self, hostname='localhost', userid=None,
 
     def _init_params(self, hostname, userid, password, virtual_host, port,
             insist, ssl, transport, connect_timeout, login_method, heartbeat):
+        if transport == 'amqp' and supports_librabbitmq():
+            transport = 'librabbitmq'
         self.hostname = hostname
         self.userid = userid
         self.password = password
@@ -403,7 +405,6 @@ def clone(self, **kwargs):
 
     def _info(self):
         transport_cls = self.transport_cls or 'amqp'
-        transport_cls = {AMQP_ALIAS: 'amqp'}.get(transport_cls, transport_cls)
         D = self.transport.default_connection_params
         hostname = self.hostname or D.get('hostname')
         if self.uri_prefix:
diff --git a/kombu/transport/__init__.py b/kombu/transport/__init__.py
index 69f943e05..7f2173620 100644
--- a/kombu/transport/__init__.py
+++ b/kombu/transport/__init__.py
@@ -12,19 +12,17 @@
 
 import sys
 
-from kombu.syn import detect_environment
+from kombu.syn import _detect_environment
 
-DEFAULT_TRANSPORT = 'amqp'
 
-AMQP_TRANSPORT = 'kombu.transport.amqplib.Transport'
-AMQP_ALIAS = 'librabbitmq'
-if detect_environment() == 'default':
-    try:
-        import librabbitmq  # noqa
-        AMQP_TRANSPORT = 'kombu.transport.librabbitmq.Transport'  # noqa
-        AMQP_ALIAS = 'amqp'                                       # noqa
-    except ImportError:
-        pass
+def supports_librabbitmq():
+    if _detect_environment() == 'default':
+        try:
+            import librabbitmq  # noqa
+            return True
+        except ImportError:
+            pass
+    return False
 
 
 def _ghettoq(name, new, alias=None):
@@ -48,7 +46,6 @@ def __inner():
 
 
 TRANSPORT_ALIASES = {
-    'amqp': AMQP_TRANSPORT,
     'pyamqp': 'kombu.transport.pyamqp.Transport',
     'amqplib': 'kombu.transport.amqplib.Transport',
     'librabbitmq': 'kombu.transport.librabbitmq.Transport',
@@ -106,7 +103,6 @@ def get_transport_cls(transport=None):
     the alias table will be consulted.
 
     """
-    transport = transport or DEFAULT_TRANSPORT
     if transport not in _transport_cache:
         _transport_cache[transport] = _get_transport_cls(transport)
     return _transport_cache[transport]