Add empty manager to provider constructor

cloudbridge/cloud/base/provider.py

@@ -8,6 +8,8 @@ try:
 except ImportError:  # Python 2
     from ConfigParser import SafeConfigParser as ConfigParser
 
+from pyeventsystem.middleware import SimpleMiddlewareManager
+
 import six
 
 from ..base.middleware import ExceptionWrappingMiddleware
@@ -85,7 +87,7 @@ class BaseCloudProvider(CloudProvider):
         self._config = BaseConfiguration(config)
         self._config_parser = ConfigParser()
         self._config_parser.read(CloudBridgeConfigLocations)
-        self._middleware = middleware_manager
+        self._middleware = middleware_manager or SimpleMiddlewareManager()
         self.add_required_middleware()
 
     @property

cloudbridge/cloud/providers/azure/provider.py

@@ -23,7 +23,7 @@ log = logging.getLogger(__name__)
 class AzureCloudProvider(BaseCloudProvider):
     PROVIDER_ID = 'azure'
 
-    def __init__(self, config, middleware_manager=[]):
+    def __init__(self, config, middleware_manager=None):
         super(AzureCloudProvider, self).__init__(config, middleware_manager)
 
         # mandatory config values

cloudbridge/cloud/providers/gcp/provider.py

@@ -196,7 +196,7 @@ class GCPCloudProvider(BaseCloudProvider):
 
     PROVIDER_ID = 'gcp'
 
-    def __init__(self, config, middleware_manager=[]):
+    def __init__(self, config, middleware_manager=None):
         super(GCPCloudProvider, self).__init__(config, middleware_manager)
 
         # Disable warnings about file_cache not being available when using

cloudbridge/cloud/providers/mock/provider.py

@@ -25,7 +25,7 @@ class MockAWSCloudProvider(AWSCloudProvider, TestMockHelperMixin):
     """
     PROVIDER_ID = 'mock'
 
-    def __init__(self, config, middleware_manager=[]):
+    def __init__(self, config, middleware_manager=None):
         self.setUpMock()
         super(MockAWSCloudProvider, self).__init__(config, middleware_manager)
 

cloudbridge/cloud/providers/openstack/provider.py

@@ -31,7 +31,7 @@ class OpenStackCloudProvider(BaseCloudProvider):
 
     PROVIDER_ID = 'openstack'
 
-    def __init__(self, config, middleware_manager=[]):
+    def __init__(self, config, middleware_manager=None):
         super(OpenStackCloudProvider, self).__init__(config,
                                                      middleware_manager)