[openstack-dev] [Neutron][python-neutronclient] Adding new options to the existing Neutron CLIs

reedip banerjee reedip14 at gmail.com
Fri Mar 18 03:06:40 UTC 2016

Dear All Neutron Developers and Reviewers,

I have a query/concern related to the parsing of options in
I would like to bring this up, as it "may" also impact the transition of
the CLIs to the openstack client as well.

NeutronClient is pretty special in its behavior, and has one pretty
powerful feature of parsing extra options. This feature states that, if the
CLI does not support an option but the API does, and the user passes a
value for this option, then the "unsupported" CLI option is parsed , and
forwarded to the Neutron Server for processing.

Currently "neutron net-create" does not support --router:external. If you
see the output of "neutron net-create -h" you would not find
"--router-external". However, this option is supported in the API since
Juno [2]. So therefore , if a user executes the following CLI
*" neutron net-create TestNetwork --router-external" *

then [1] would be observed as an output.

Now the query/concern comes next....
Any option which is not supported by the CLI is open to the above parsing.
Therefore , for net-create and net-update, all the following are possible:

*neutron net-create --router:external=True TESTNetwork --(A)*
*neutron net-create --router:external TESTNetwork  --(B)*
*neutron net-create **TESTNetwork **--router:external **--(C)*
*neutron net-create **TESTNetwork **--router:external=True **--(D)*
*neutron net-create **TESTNetwork **--router:external True **--(E)*

However, user is not aware of the --router:external option because it is
not visible in the HELP section ( this is true for other CLI options as

In order to demonstrate these options to the User, we have to update
add_known_arguments function to display them. And once they are known to
the CLI, the parsing changes, and some of the options from (A) to (E) may
not be supported ( Please see [3] for an ongoing, though now dormant,
discussion ).

Note that this discussion is not limited only to net-create, but possibly
other CLIs as well which do not completely expose the Options which the API
can support.I am , however, taking the* net-create* example as a case-study.

I would like to know how we can move forward in this regards:

-- Should NeutronClient continue to support all options from (A) to (E),
but deprecate some of them in Openstack Client?

-- Should we deprecate them in NeutronClient itself, so that the users are
comfortable with the options when the migration to Openstack Client occurs?

-- Any other suggestions....

[1]: http://paste.openstack.org/show/491032/

[3]: https://review.openstack.org/#/c/137279/

Thanks and Regards,
Reedip Banerjee
IRC: reedip
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