suggest commands if command is not recognized

tab-completion spits out the arguments

$ openstack user <tab>

create delete list role set show

Can you check with the latest python-openstackclient?

@Amey, you're right, the tab completion works. But even then, if I type 'openstack user', it says:

ERROR: openstack Unknown command ['user']

'user' definitely is not an unknown command. At the very least, it should be worded better. Better would be if it says 'user' needs another argument out of these: create delete list role set show

not sure how to fix this, but its definitely bad UX (even with tab completion). Wishlisting.

@Steve maybe can get experience from keystoneclient,

if i type 'keystone user-get', it says:

keystone user-get <tab>
usage: keystone user-get <user>
keystone user-get: error: too few arguments

@Amey i just used the latest python-openstackclient (at branch 'stable/kilo'), but the tab-completion is not useful...
ps. i installed openstack with devstack

I think this problem should be solved in the "cliff".

see how 'openstack <cmd> help' work , maybe can got some spark
the code is at cliff/help.py

1> exact match
$ openstack user list help
usage: openstack user list [-h] [-f {csv,html,json,table,value,yaml}]
                           [-c COLUMN] [--max-width <integer>]
                           [--quote {all,minimal,none,nonnumeric}]
                           [--project <project>] [--long]
openstack user list: error: unrecognized arguments: help

2> fuzzy match
$ openstack user help
Command "user" matches:
  user create
  user delete
  user list
  user role list
  user set
  user show

compare with 'openstack user', there not raise a ValueError,
but try to find a fuzzy match and print it out
good UX!

3> not match
$openstack usre help
ERROR: openstack Unknown command ['usre', 'help']

so, when type 'openstack user':
     1> try to find an exact match; (obviously, can't find )
     2> try to find a fuzzy match; it could be:
              ' openstack user list'
              'openstack user show'
              'openstack user create'
               ...
     3> if also can't fuzzy match , raise ValueError(if debug) or log error

fix for this topic is at: https://review.openstack.org/#/c/202053/

Marked the OSC part invalid as I think the cliff change will fix that.

@terry, i was hoping to keep it as valid for OSC, so we could track when we depend on a new cliff :)

Reviewed: https://review.openstack.org/202053
Committed: https://git.openstack.org/cgit/openstack/cliff/commit/?id=3396764571f5e18f99a63f1f1160a0a6a1b3097a
Submitter: Jenkins
Branch: master

commit 3396764571f5e18f99a63f1f1160a0a6a1b3097a
Author: kafka <email address hidden>
Date: Wed Jul 15 16:16:36 2015 +0800

    Add command fuzzy matching

    The command 'openstack user' throws error with no helpful message even though 'openstack user list' works,
    that is really a bad UX. This patch adds fuzzy matching to print the most similar command when user mistypes
    the command.
    Use Demeraou-Levenshtein algorithm to find the best similarity. It takes experience from Git's
    algothrim inplement https://github.com/git/git/commit/8af84dadb142f7321ff0ce8690385e99da8ede2f

    $ openstack user
    openstack: 'user' is not an openstack command. See 'openstack --help'.
    Did you mean one of these?
      user create
      user delete
      user list
      user password set
      user set
      user show
      consumer create
      consumer delete
      consumer list
      consumer set
      consumer show

    Change-Id: Id8732504c0b36177319fc33fae7e630b7b714be7
    Closes-Bug: 1462192