CLI Sorting Argument Guidelines

To varying degrees, the REST APIs for various projects support sort keys and sort directions; these sorting options are exposed as python client arguments. This specification defines the syntax for these arguments so that there is consistency across clients.

Problem description

Different projects have implemented the CLI sorting options in different ways. For example:

  • Nova: –sort key1[:dir1],key2[:dir2]

  • Cinder: –sort_key <key> –sort_dir <dir>

  • Ironic: –sort-key <key> –sort-dir <dir>

  • Neutron: –sort-key <key1> –sort-dir <dir1>

    –sort-key <key2> –sort-dir <dir2>

  • Glance (under review): –sort-key <key1> –sort-key <key2> –sort-dir <dir>

Proposed change

Based on mailing list feedback (see References sections), the consensus is to follow the syntax that nova currently implements: –sort <key>[:<direction>]

Where the –sort parameter is comma-separated and used to specify one or more sort keys and directions. A sort direction is optionally appended to each key and is either ‘asc’ for ascending or ‘desc’ for descending.

For example:

  • nova list –sort display_name
  • nova list –sort display_name,vm_state
  • nova list –sort display_name:asc,vm_state:desc
  • nova list –sort display_name,vm_state:asc

Unfortunately, the REST APIs for each project support sorting to different degrees:

  • Nova and Neutron: Multiple sort keys and multiple sort directions
  • Cinder and Ironic: Single sort key and single sort direction (Note: approved kilo spec in Cinder for adding adding for multiple key and direction support)
  • Glance: Multiple sort keys and single sort direction

In the event that the corresponding REST APIs do not support multiple sort keys and multiple sort directions, the client may:

  • Support a single key and direction
  • Support multiple keys and directions and implement any remaining sorting in the client


Each sort key and associated direction could be supplied independently, for example:

–sort-key key1 –sort-dir dir1 –sort-key key2 –sort-dir dir2



Primary assignee:
  • Cinder: Steven Kaufer (kaufer)
  • Glance: Mike Fedosin (mfedosin)

Work Items

  • Deprecate –sort_key and –sort_dir and add support for –sort
  • Note that the Cinder REST API currently supports only a single sort key and direction so the CLI will have the same restriction, this restriction can be lifted once the following is implemented:
  • Deprecate –sort-key and –sort-dir and add support for –sort



Release Name Description
Kilo Introduced