Python client output indistinguishable between "None" string and NoneType

[Shrirang Phadke]

If "None" string is set as value of any resource attribute (Instance Name, Volume Name, Project Name) then it is hard to distinguish between "None" string and NoneType as attribute value.

Both are listed ambigously as: http://i.imgur.com/3sFNaEP.jpg

Amazon uses hyphen '-' to denote NoneType values. I am trying to get this fix in python-cinderclient (https://review.openstack.org/#/c/64665/)

Same fix might also be applied to other python clients

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/65680

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/65680
Committed: https://git.openstack.org/cgit/openstack/python-novaclient/commit/?id=1627908b182ca9afd54ce695c820cd56d70a44df
Submitter: Jenkins
Branch: master

commit 1627908b182ca9afd54ce695c820cd56d70a44df
Author: Shrirang Phadke <email address hidden>
Date: Tue Jan 7 22:08:28 2014 +0530

    Fixes ambiguous cli output between "None" and NoneType

    Print hyphen(-) in python client output when attribute value is not
    set(NoneType) so that it is distinguishable between "None" string
    and NoneType value.

    Change-Id: I5ec0f39f13aca45fa95ddb59472c20207c63bf91
    Closes-Bug: #1266414

[Marcos Lobo (marcos-fermin-lobo)]

In the case of python-keystoneclient I think that it's not necessary because now, on functions like print_list there is this code:

....
if field in formatters:
                row.append(formatters[field](o))
            else:
                field_name = field.lower().replace(' ', '_')
                data = getattr(o, field_name, '')
                if data is None:
                    data = ''
                row.append(data)
....

if data is None then data equals to empty string. It is necessary to change it to equals to hyphen string?. I'm not sure.

[Rohan (kanaderohan)]

Since the python-novaclient will now be showing hyphen "-" for NoneType data. IMO , we should keep this behavior consistent across other python-clients.

Also, hyphen "-" makes it easier to identify that the value is NoneType instead of a blank string "".
It is not a major change to the code, hence i think we should go ahead with displaying hyphen "-" instead of NoneType in all official clients.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/68617

[melanie witt (melwitt)]

novaclient 2.16.0 released on 2/26/2014

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/102955

[Dolph Mathews (dolph)]

"Amazon uses hyphen" isn't a justification: why should we use a hyphen instead of "None"?

Why would we care less about disambiguating between '-' and null value versus 'None' and a null value?

[pritesh (pritesh)]

@Dolph: its not about amazon vs openstack, its about getting your scripts working for both without any special cases.

[Dolph Mathews (dolph)]

I hope you're not writing bash scripts against both :( Use the python APIs, not the human interface.

[pritesh (pritesh)]

@Dolph: I am not, its just that i am trying to keep interface consistent across nova, sahara, etc.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/102955
Committed: https://git.openstack.org/cgit/openstack/python-saharaclient/commit/?id=22a413bcd7391f6df11cf8ee0e340babb6f339ad
Submitter: Jenkins
Branch: master

commit 22a413bcd7391f6df11cf8ee0e340babb6f339ad
Author: Shrirang Phadke <email address hidden>
Date: Tue Jan 7 22:08:28 2014 +0530

    Fixes ambiguous cli output between "None" and NoneType

    Print hyphen(-) in python client output when attribute value is not
    set(NoneType) so that it is distinguishable between "None" string
    and NoneType value.

    Cherry-Pick: I5ec0f39f13aca45fa95ddb59472c20207c63bf91
    Change-Id: I8a907e7453df711605d28bb97492f747adc282e0
    Closes-Bug: #1266414

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/156489

[Steve Martinelli (stevemar)]

for keystoneclient we have deprecated the CLI in favor of OpenStackClient which does not print "None" or a hyphen "-", but rather uses prettytable and cliff, which uses a whitespace ' '.

the result is very nice for scripting with awk and grep, but scripters can also use smarter functions like -c and -v to get the value of a specific column

[Akihiro Motoki (amotoki)]

In neutronclient, we don't change the current behavior because:

* it is backward-incompatible. If a user parses an output, changing an empty string to '-' breaks their script.
* If we use a hyphen instead, then we cannot distinguish '-' from None. It just changes a problem.

In a case of cliff-based client such as neutronclient or openstackclient, we can select an output option (table, json, yaml).
If you need detail values with their type, we can use JSON formatter.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Akihiro Motoki (<email address hidden>) on branch: master
Review: https://review.openstack.org/156489
Reason: There is no reply from the author over 8 weeks, and we have many objections on this change.

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/340103

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/340113

[OpenStack Infra (hudson-openstack)]

Change abandoned by PanFengyun (<email address hidden>) on branch: master
Review: https://review.openstack.org/340113