keypair-show fails with "ERROR: can't set attribute"

[Roman Podoliaka]

Steps to reproduce on a clean DevStack deployment:
1. Create a new key pair:
malor@devstack:~/devstack$ nova keypair-add test
...

2. Show details about the given key pair:
malor@devstack:~/devstack$ nova keypair-show test
ERROR: can't set attribute

Running nova client with --debug allows to see the actual trace back:

DEBUG (shell:740) can't set attribute
Traceback (most recent call last):
  File "/opt/stack/python-novaclient/novaclient/shell.py", line 737, in main
    OpenStackComputeShell().main(map(strutils.safe_decode, sys.argv[1:]))
  File "/opt/stack/python-novaclient/novaclient/shell.py", line 673, in main
    args.func(self.cs, args)
  File "/opt/stack/python-novaclient/novaclient/v1_1/shell.py", line 2345, in do_keypair_show
    keypair = cs.keypairs.get(args.keypair)
  File "/opt/stack/python-novaclient/novaclient/v1_1/keypairs.py", line 55, in get
    return self._get("/os-keypairs/%s" % base.getid(keypair), "keypair")
  File "/opt/stack/python-novaclient/novaclient/base.py", line 141, in _get
    return self.resource_class(self, body[response_key], loaded=True)
  File "/opt/stack/python-novaclient/novaclient/base.py", line 408, in __init__
    self._add_details(info)
  File "/opt/stack/python-novaclient/novaclient/v1_1/keypairs.py", line 35, in _add_details
    setattr(self, k, v)
AttributeError: can't set attribute
ERROR: can't set attribute

[kesten broughton (dathomir)]

I see the same error in the terminal output of the savanna process when I try to launch the cluster:

-- commandline output
stack@vmware-controller:~/savanna-venv$ http $SAVANNA_URL/clusters X-Auth-Token:$AUTH_TOKEN < cluster_create.json
HTTP/1.1 500 INTERNAL SERVER ERROR
Content-Length: 111
Content-Type: application/json
Date: Mon, 16 Sep 2013 05:08:10 GMT

{
    "error_code": 500,
    "error_message": "Error occurred during validation",
    "error_name": "INTERNAL_SERVER_ERROR"
}

--- term output

2013-09-15 21:50:52.608 23743 ERROR savanna.utils.api [-] Request aborted with status code 500 and message 'Error occurred during validation'
2013-09-15 21:50:52.608 23743 ERROR savanna.utils.api [-] Traceback (most recent call last):
  File "/home/stack/savanna-venv/local/lib/python2.7/site-packages/savanna/service/validation.py", line 37, in handler
    validator(**kwargs)
  File "/home/stack/savanna-venv/local/lib/python2.7/site-packages/savanna/service/validations/clusters.py", line 53, in check_cluster_create
    b.check_keypair_exists(data['user_keypair_id'])
  File "/home/stack/savanna-venv/local/lib/python2.7/site-packages/savanna/service/validations/base.py", line 162, in check_keypair_exists
    nova.client().keypairs.get(keypair)
  File "/home/stack/savanna-venv/local/lib/python2.7/site-packages/novaclient/v1_1/keypairs.py", line 55, in get
    return self._get("/os-keypairs/%s" % base.getid(keypair), "keypair")
  File "/home/stack/savanna-venv/local/lib/python2.7/site-packages/novaclient/base.py", line 140, in _get
    return self.resource_class(self, body[response_key], loaded=True)
  File "/home/stack/savanna-venv/local/lib/python2.7/site-packages/novaclient/base.py", line 387, in __init__
    self._add_details(info)
  File "/home/stack/savanna-venv/local/lib/python2.7/site-packages/novaclient/v1_1/keypairs.py", line 35, in _add_details
    setattr(self, k, v)
AttributeError: can't set attribute

[kesten broughton (dathomir)]

The trace is fairly helpful.
The error comes from _add_details on the setattr line.
Keypairs inherits from base.Resource in base.py.
Note the difference and the comment (setattr is surrounded with a try catch in base.Resource.
If you wrap the setattr in KeyPair's _add_details, the error goes away.

To fix:
locate v1_1/keypairs.py
for me they were located here:
/opt/stack/python-novaclient/novaclient/v1_1/keypairs.py
/home/stack/savanna-venv/lib/python2.7/site-packages/novaclient/v1_1/keypairs.py

I also deleted the .pyc versions of these files, though that shouldn't be necessary.

Test it first on
nova keypair-list
if that succeeds then stop the savana process and restart (from the parent directory to savanna-venv) with
savanna-venv/bin/python savanna-venv/bin/savanna-api --config-file savanna-venv/etc/savanna.conf

# KeyPair in keypairs.py
    def _add_details(self, info):
        dico = 'keypair' in info and \
            info['keypair'] or info
        for (k, v) in dico.items(): ## wrap this for loop in a try/catch like in base.Resource
            setattr(self, k, v)

# base.Resource in base.py
    def _add_details(self, info):
        for (k, v) in six.iteritems(info):
            try:
                setattr(self, k, v)
                self._info[k] = v
            except AttributeError:
                # In this case we already defined the attribute on the class
                pass

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/46897

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/47724
Committed: http://github.com/stackforge/savanna/commit/3e344d41a82b43b2a3c68b5c43486841ba3a626a
Submitter: Jenkins
Branch: master

commit 3e344d41a82b43b2a3c68b5c43486841ba3a626a
Author: Sergey Lukjanov <email address hidden>
Date: Sun Sep 22 12:29:14 2013 +0400

    Temporarily fixes bug #1223934

    It could be removed when fix for this bug will be released in novaclient
    and novaclient version in requirements will be updated.

    Fixes: bug #1223934

    Change-Id: Idb019d5905e21948126e84c099d2abb524e7eba9

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/46897
Committed: http://github.com/openstack/python-novaclient/commit/9e8dd063c6c4215ebda25d0199cec3fb64a81837
Submitter: Jenkins
Branch: master

commit 9e8dd063c6c4215ebda25d0199cec3fb64a81837
Author: Roman Podolyaka <email address hidden>
Date: Tue Sep 17 10:21:03 2013 +0300

    Fix AttributeError in Keypair._add_details()

    _add_details() method copies keypair attributes retrieved
    from Nova to an instance of Keypair class. Trying to set
    attribute 'id' fails with AttributeError, because Keypair
    class has a read-only property 'id'.

    We can safely omit setting of attribute 'id', because it's
    just an implementation detail (the id of a table row in a
    database), and keypairs for a given tenant are uniquely
    identified using attribute 'name'.

    Fixes bug 1223934

    Change-Id: I1045730e47e9e6ad31fcdfbaefdad77e2f3b2c3e

[melanie witt (melwitt)]

novaclient 2.16.0 released on 2/26/2014