cinderlib.get_connector_properties raises an exception

[Gorka Eguileor]

[Bug reported by Ray Tan <tanshaolong> in old cinderlib repository https://github.com/Akrog/cinderlib/issues/18]

We get an exception when calling "get_connector_properties" in steps indicated the connection documentation for cases where we are sharing the metadata storage:
https://docs.openstack.org/cinderlib/latest/topics/connections.html#with-access-to-the-metadata-persistence-storage

Exception raised is:

>>> connector_dict = cl.get_connector_properties('sudo', '10.10.2.99', True, False)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/site-packages/os_brick/utils.py", line 137, in trace_logging_wrapper
    return f(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/os_brick/initiator/connector.py", line 256, in get_connector_properties
    enforce_multipath=enforce_multipath,
  File "/usr/lib/python2.7/site-packages/os_brick/initiator/connectors/base.py", line 56, in get_connector_properties
    execute=kwargs.get('execute')))
  File "/usr/lib/python2.7/site-packages/os_brick/initiator/linuxscsi.py", line 161, in is_multipath_running
    run_as_root=True, root_helper=root_helper)
  File "/usr/lib/python2.7/site-packages/os_brick/privileged/rootwrap.py", line 169, in execute
    return execute_root(*cmd, **kwargs)
  File "/usr/lib/python2.7/site-packages/oslo_privsep/priv_context.py", line 204, in _wrap
    self.start()
  File "/usr/lib/python2.7/site-packages/oslo_privsep/priv_context.py", line 215, in start
    channel = daemon.RootwrapClientChannel(context=self)
  File "/usr/lib/python2.7/site-packages/oslo_privsep/daemon.py", line 327, in __init__
    raise FailedToDropPrivileges(msg)
oslo_privsep.daemon.FailedToDropPrivileges: privsep helper command exited non-zero (1)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/649552

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/649552
Committed: https://git.openstack.org/cgit/openstack/cinderlib/commit/?id=502f4ce9f47806a21c132cdb9cea7960f0c021c5
Submitter: Zuul
Branch: master

commit 502f4ce9f47806a21c132cdb9cea7960f0c021c5
Author: Gorka Eguileor <email address hidden>
Date: Wed Apr 3 11:53:18 2019 +0200

    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