Fix get_connector_properties

We get exception oslo_privsep.daemon.FailedToDropPrivileges when calling
cinderlib.get_connector_properties.

This is because we make it point to OS-Brick's original method, which we
later replace when we do the init in nos-brick.  So cinderlib always
call the replaced method, while cinderlib users will be calling the
original OS-Brick method that hasn't replaced the privsep code.

This patch fixes this by assigning our get_connector_properties method
to the cinderlib method during the nos-brick initialization.

We also have a tiny doc change where we were saying connection instead
of connector, and some cosmetic changes in nos_brick to improve
readability, since we were using acronyms bgcp and bcp, which we now
replace for some more meaningful names.

Closes-Bug: #1822976
Change-Id: I627289418d52bdab826d1cf1a941e5671aaf2239

cinderlib/__init__.py

@@ -41,5 +41,6 @@ dumps = serialization.dumps
 setup = cinderlib.setup
 Backend = cinderlib.Backend
 
+# This gets reassigned on initialization by nos_brick.init
 get_connector_properties = objects.brick_connector.get_connector_properties
 list_supported_drivers = cinderlib.Backend.list_supported_drivers

cinderlib/nos_brick.py

@@ -26,6 +26,7 @@ Here we take care of:
 Some of these changes may be later moved to OS-Brick. For now we just copied it
 from the nos-brick repository.
 """
+from __future__ import absolute_import
 import errno
 import functools
 import os
@@ -42,6 +43,8 @@ from oslo_utils import fileutils
 from oslo_utils import strutils
 import six
 
+import cinderlib
+
 
 LOG = logging.getLogger(__name__)
 
@@ -237,19 +240,19 @@ def init(root_helper='sudo'):
     ROOT_HELPER = root_helper
     priv_context.init(root_helper=[root_helper])
 
-    existing_bgcp = connector.get_connector_properties
-    existing_bcp = connector.InitiatorConnector.factory
+    brick_get_connector_properties = connector.get_connector_properties
+    brick_connector_factory = connector.InitiatorConnector.factory
 
-    def my_bgcp(*args, **kwargs):
+    def my_get_connector_properties(*args, **kwargs):
         if len(args):
             args = list(args)
             args[0] = ROOT_HELPER
         else:
             kwargs['root_helper'] = ROOT_HELPER
         kwargs['execute'] = _execute
-        return existing_bgcp(*args, **kwargs)
+        return brick_get_connector_properties(*args, **kwargs)
 
-    def my_bgc(protocol, *args, **kwargs):
+    def my_connector_factory(protocol, *args, **kwargs):
         if len(args):
             # args is a tuple and we cannot do assignments
             args = list(args)
@@ -262,11 +265,13 @@ def init(root_helper='sudo'):
         if protocol == 'rbd':
             factory = RBDConnector
         else:
-            factory = functools.partial(existing_bcp, protocol)
+            factory = functools.partial(brick_connector_factory, protocol)
 
         return factory(*args, **kwargs)
 
-    connector.get_connector_properties = my_bgcp
-    connector.InitiatorConnector.factory = staticmethod(my_bgc)
+    # Replace OS-Brick method and the reference we have to it
+    connector.get_connector_properties = my_get_connector_properties
+    cinderlib.get_connector_properties = my_get_connector_properties
+    connector.InitiatorConnector.factory = staticmethod(my_connector_factory)
     if hasattr(rootwrap, 'unlink_root'):
         rootwrap.unlink_root = unlink_root

doc/source/topics/connections.rst

@@ -122,6 +122,7 @@ key-value storage provided by the persistence plugin:
 
 .. code-block:: python
 
+   import socket
    import cinderlib as cl
 
    cl.setup(persistence_config=persistence_config)
@@ -173,7 +174,7 @@ No access to the metadata persistence storage
 This is more inconvenient, as you'll have to handle the data exchange manually
 as well as the *OS-Brick* library calls to do the attach/detach.
 
-First we need to get the connection information on the host that is going to do
+First we need to get the connector information on the host that is going to do
 the attach:
 
 .. code-block:: python