Printing novaclient.v1_1.servers.Server object causes AttributeError

[Christian Huebner]

I tried printing a novaclient.v1_1 server object returned by novaclient.v1_1.server.Server.interface_list() with this code:

Note: self.clients[item['tenant'] is an instance of novaclient.v1_1.client

nvlist = self.clients[item['tenant']].servers.list()

for ins in nvlist:
    lst = ins.interface_list()
    print type(lst[0])
    print lst

This results in:
<class 'novaclient.v1_1.servers.Server'>
Traceback (most recent call last):
  File "./collect.py", line 38, in <module>
    points = cl.score()
  File "/home/stack/Cert/mcoe/instances.py", line 38, in score
    print lst[0]
  File "/opt/stack/python-novaclient/novaclient/v1_1/servers.py", line 36, in __repr__
    return "<Server: %s>" % self.name
  File "/opt/stack/python-novaclient/novaclient/base.py", line 458, in __getattr__
    raise AttributeError(k)
AttributeError: name

The issue here is that neither the novaclient.v1_1.servers.Server object nor its base.Resource parent class returned by interface_list has a name field:

[['HUMAN_ID', 'NAME_ATTR', '__class__', '__delattr__', '__dict__', '__doc__', '__eq__', '__format__', '__getattr__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_add_details', '_info', '_loaded', 'add_fixed_ip', 'add_floating_ip', 'add_security_group', 'backup', 'change_password', 'clear_password', 'confirm_resize', 'create_image', 'delete', 'diagnostics', 'evacuate', 'fixed_ips', 'force_delete', 'get', 'get_console_output', 'get_password', 'get_spice_console', 'get_vnc_console', 'human_id', 'interface_attach', 'interface_detach', 'interface_list', 'is_loaded', 'list_security_group', 'live_migrate', 'lock', 'mac_addr', 'manager', 'migrate', 'net_id', 'networks', 'pause', 'port_id', 'port_state', 'reboot', 'rebuild', 'remove_fixed_ip', 'remove_floating_ip', 'remove_security_group', 'rescue', 'reset_network', 'reset_state', 'resize', 'restore', 'resume', 'revert_resize', 'set_loaded', 'shelve', 'shelve_offload', 'start', 'stop', 'suspend', 'unlock', 'unpause', 'unrescue', 'unshelve', 'update']

Possible remedies:
 - A name field could be added to base.Resource
 - Another way could be used to identify the interface returned, maybe IP or MAC of the interface
 - the __repr__ method could be removed entirely if deemed unnecessary

[Sahid Orentino (sahid-ferdjaoui)]

This needs more information about the version of the client and server used.

[Christian Huebner (ossarchitect)]

This bug was observed in the current version of devstack (Havana)

Nova API is v1.1 as mentioned before. Version of the nova client is 2.15.0.77 as seen here:

$ nova --version
2.15.0.77

Nova version is 2013.2.1 from /opt/stack/nova/setup.cfg

I confirmed the problem is present and reproducible with the versions mentioned above.

The issue is that the __repr__ method in the novaclient.v1_1.servers.Server class is trying to return a class field (self.name) that does not exist.

There are three possible solutions for this issue:

1) Add and populate a self.name field to the novaclient.v1_1.servers.Server class (preferable)

2) Remove the __repr__ method of the class.

This is the actual code from novaclient/v1_1/servers.py:
 32 class Server(base.Resource):
 33 HUMAN_ID = True
 34
 35 def __repr__(self):
 36 return "<Server: %s>" % self.name

The repr method has no task other than to return the name, which does not exist.

3) Modify the __repr__ method to return something else that does exist.

My recommendation is to add and populate a name field.

[Christian Huebner (ossarchitect)]

if the __repr__ method is removed altogether this is what print lst returns:

[<Server fixed_ips=[{u'subnet_id': u'f1ad93ad-2967-46ba-b403-e8cbbe65f7fa', u'ip_address': u'10.2.0.96'}], mac_addr=fa:16:3e:4c:37:c8, net_id=d7745cf5-63f9-4883-b0ae-983f061e4f23, port_id=f35079da-36d5-4513-8ec1-0298d703f70e, port_state=ACTIVE>]

This would be more much more useful than than getting an attribute error.

it probably would be best to just remove __repr__ altogether, this gives all the information needed on this interface.

[Kun Huang (academicgareth)]

I got this problem again, but don't know the reason. My environment is built by devstack, which is about current codes

[ZhiQiang Fan (aji-zqfan)]

this is because the interface has no attributes named 'name', when initialize the Server object, it will inject attributes with the dict (here is the fixed_ips dict), since the fixed ips has no name, it hiccups

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/82443

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/82443
Committed: https://git.openstack.org/cgit/openstack/python-novaclient/commit/?id=6fbddcb4b629608a6b5ff556990c13563a36f858
Submitter: Jenkins
Branch: master

commit 6fbddcb4b629608a6b5ff556990c13563a36f858
Author: ZhiQiang Fan <email address hidden>
Date: Mon Mar 24 15:29:01 2014 +0800

    Avoid AttributeError in servers.Server.__repr__

    servers.Server represents various object now, and some of them may
    don't have attribute 'name', for example, the interface_list() result
    object. It will cause AttributeError when we try to format string with
    such object, so I add a check for the 'name' attribute in __repr__
    method, it will use 'unknown-name' instead when 'name' is not found.

    Change-Id: If4757d5d73721774543d58a4cc875710a6013f34
    Closes-Bug: #1280453