couchdb can now be imported without couchdb dependency

kombu/transport/couchdb.py

@@ -11,7 +11,6 @@ CouchDB transport.
 from __future__ import absolute_import
 
 import socket
-import couchdb
 
 from anyjson import loads, dumps
 
@@ -21,6 +20,11 @@ from kombu.utils.encoding import bytes_to_str
 
 from . import virtual
 
+try:
+    import couchdb
+except ImportError:  # pragma: no cover
+    couchdb = None   # noqa
+
 DEFAULT_PORT = 5984
 DEFAULT_DATABASE = 'kombu_default'
 
@@ -112,20 +116,27 @@ class Transport(virtual.Transport):
     connection_errors = (
         virtual.Transport.connection_errors + (
             socket.error,
-            couchdb.HTTPError,
-            couchdb.ServerError,
-            couchdb.Unauthorized)
+            getattr(couchdb, 'HTTPError', None),
+            getattr(couchdb, 'ServerError', None),
+            getattr(couchdb, 'Unauthorized', None),
+        )
     )
     channel_errors = (
         virtual.Transport.channel_errors + (
-            couchdb.HTTPError,
-            couchdb.ServerError,
-            couchdb.PreconditionFailed,
-            couchdb.ResourceConflict,
-            couchdb.ResourceNotFound)
+            getattr(couchdb, 'HTTPError', None),
+            getattr(couchdb, 'ServerError', None),
+            getattr(couchdb, 'PreconditionFailed', None),
+            getattr(couchdb, 'ResourceConflict', None),
+            getattr(couchdb, 'ResourceNotFound', None),
+        )
     )
     driver_type = 'couchdb'
     driver_name = 'couchdb'
 
+    def __init__(self, *args, **kwargs):
+        if couchdb is None:
+            raise ImportError('Missing couchdb library (pip install couchdb)')
+        super(Transport, self).__init__(*args, **kwargs)
+
     def driver_version(self):
         return couchdb.__version__