nova list --fields fails if no VMs are running

[Paul]

The fix for bug #1522989 broke the list command if no VMs are running. When the list of VMs is empty there are no fields to validate so specifying fields always returns an error. Field validation should be skipped if there are no VMs to make the behaviour of "nova list --fields" consistent with "nova list"

With VMs running:
~$ nova list --fields metadata,created,networks
+--------------------------------------+------------------------------------------------------------+----------------------+-----------------------------------
----------------------+
| ID | Metadata | Created | Networks
                      |
+--------------------------------------+------------------------------------------------------------+----------------------+-----------------------------------
----------------------+
| 4072c7c5-eab4-45f3-a3b8-1b0d010ddf7c | {u'instance': u'my-instance', u'vnfc-type': u'management'} | 2016-09-19T03:11:13Z | internal-network=10
.0.0.3, 192.168.2.68 |
+--------------------------------------+------------------------------------------------------------+----------------------+-----------------------------------
----------------------+

No VMs running:
~$ nova list --fields metadata,created,networks
ERROR (CommandError): Non-existent fields are specified: [u'metadata', u'created', u'networks']

~$ nova list
+----+------+--------+------------+-------------+----------+
| ID | Name | Status | Task State | Power State | Networks |
+----+------+--------+------------+-------------+----------+
+----+------+--------+------------+-------------+----------+

[Ali Jabbar (jabbar-ali)]

Could you please share what are the steps for reproducing this issue !!

I am not seeing in normal executions

stack@cinv-V:/home/cinv/devstack$ nova list --fields metadata,created,networks
+--------------------------------------+----------+----------------------+----------+
| ID | Metadata | Created | Networks |
+--------------------------------------+----------+----------------------+----------+
| 3beff4cd-a192-4633-99c2-665cde76914f | {} | 2016-10-02T06:40:53Z | |
| 468c10bf-6def-47d8-a804-d69b4c34658e | {} | 2016-10-02T06:46:40Z | |
| 4bb5e5a0-2812-489c-a41e-de04ee0be851 | {} | 2016-10-02T06:33:01Z | |
| bb7426e1-17c7-408d-bae4-278cdf8a44d8 | {} | 2016-10-02T06:45:16Z | |
| d95f5047-692b-4672-a377-60d7e7ddb9bb | {} | 2016-10-02T06:39:34Z | |
+--------------------------------------+----------+----------------------+----------+
stack@cinv-V:/home/cinv/devstack$ nova list
+--------------------------------------+-----------------------------------------------+--------+------------+-------------+----------+
| ID | Name | Status | Task State | Power State | Networks |
+--------------------------------------+-----------------------------------------------+--------+------------+-------------+----------+
| 3beff4cd-a192-4633-99c2-665cde76914f | Instance-25b34978-c701-4e70-a7e9-56b3f9754a10 | ERROR | - | Shutdown | |
| 468c10bf-6def-47d8-a804-d69b4c34658e | Instance-6167a8ff-6545-4d8d-8dd3-1b8424b0eda5 | ERROR | - | Shutdown | |
| bb7426e1-17c7-408d-bae4-278cdf8a44d8 | server-1be21545-d03d-4d35-b254-d2d50af09c7e | ERROR | - | Shutdown | |
| d95f5047-692b-4672-a377-60d7e7ddb9bb | server-5f7d5fad-3896-4288-a881-2abaa4a8b258 | ERROR | - | Shutdown | |
| 4bb5e5a0-2812-489c-a41e-de04ee0be851 | server-8bb7748d-e519-45f6-aed1-2d666839647b | ERROR | - | Shutdown | |
+--------------------------------------+-----------------------------------------------+--------+------------+-------------+----------+
stack@cinv-V:/home/cinv/devstack$
stack@cinv-V:/home/cinv/devstack$
stack@cinv-V:/home/cinv/devstack$ nova delete 3beff4cd-a192-4633-99c2-665cde76914f
Request to delete server 3beff4cd-a192-4633-99c2-665cde76914f has been accepted.
stack@cinv-V:/home/cinv/devstack$
stack@cinv-V:/home/cinv/devstack$
stack@cinv-V:/home/cinv/devstack$ nova list | grep ERROR
| 468c10bf-6def-47d8-a804-d69b4c34658e | Instance-6167a8ff-6545-4d8d-8dd3-1b8424b0eda5 | ERROR | - | Shutdown | |
| bb7426e1-17c7-408d-bae4-278cdf8a44d8 | server-1be21545-d03d-4d35-b254-d2d50af09c7e | ERROR | - | Shutdown | |
| d95f5047-692b-4672-a377-60d7e7ddb9bb | server-5f7d5fad-3896-4288-a881-2abaa4a8b258 | ERROR | - | Shutdown | |
| 4bb5e5a0-2812-489c-a41e-de04ee0be851 | server-8bb7748d-e519-45f6-aed1-2d666839647b | ERROR | - | Shutdown | |
stack@cinv-V:/home/cinv/devstack$
stack@cinv-V:/home/cinv/devstack...

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/396074

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/396074
Committed: https://git.openstack.org/cgit/openstack/python-novaclient/commit/?id=b98a033d1673b8da8ca261b1dfc6cb0bd6996e9d
Submitter: Jenkins
Branch: master

commit b98a033d1673b8da8ca261b1dfc6cb0bd6996e9d
Author: Arvinder Singh <email address hidden>
Date: Thu Nov 10 15:47:03 2016 +0530

    Fix 'nova list --fields' error in no instances case

    Code changes done so that nova list command with filters run without
    error when no instances are present. It shows a blank table instead of
    error message.

    Closes-Bug: #1624978
    Change-Id: Iff879a520c607b8205a3ce5db8fc92287253dbe0
    Co-Authored-By: Diana Clarke <email address hidden>

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/python-novaclient 8.0.0 release.