[Freeipa-devel] Converting plugin output

[Jan Cholasta]

Hi,

On 18.3.2016 15:26, Christian Heimes wrote:
> Hi,
>
> I'd like to use FreeIPA's RPC interface from Ansible directly. But the
> output of plugins is rather unfriendly and unpythonic:
>
>>>> print(api.Command.dnsconfig_show())
> {u'result': {u'dn': u'cn=dns,dc=ipa,dc=example', u'idnsallowsyncptr':
> (u'FALSE',)}, u'value': None, u'summary': None}
>
> Please notice (u'FALSE',) instead of False.

This is how the framework does things - there is no internal consistency 
and no singular place where coding of values is handled, lot of the 
output is generated by ad-hoc code somewhere in post_callbacks. 
Unfortunately this is not easily fixable.

>
>
> I have written a simple function that uses the parameter definitions to
> convert most values automatically:
>
> def converter(plugin, *args, **kwargs):
>      response = plugin(*args, **kwargs)
>      params = {p.name: p for p in plugin.obj.takes_params}
>      if hasattr(plugin, 'output_params'):
>          params.update({p.name: p for p in plugin.output_params()})
>      results = response['result']
>      if isinstance(results, dict):
>          results = [results]
>      for result in results:
>          for key, value in result.iteritems():
>              param = params.get(key)
>              if param is None:
>                  continue
>              if (value and not param.multivalue and
>                      isinstance(value, (list, tuple))):
>                  if len(value) > 1:
>                      raise ValueError(key, value)
>                  value = value[0]
>              result[key] = param.convert(value)
>      return response
>
> It works like a charm for several plugins:
>
>>>> print(converter(api.Command.dnsconfig_show))
> {u'result': {u'dn': u'cn=dns,dc=ipa,dc=example', u'idnsallowsyncptr':
> False}, u'value': None, u'summary': None}
>
>
> But it is failing for some plugins like user_find(). The plugin returns
> u'memberof_group': (u'admins', u'trust admins'). However
> global_output_params defines the value as an optional and single valued
> string:
>
>      Str('memberof_group?', label=_('Member of groups')).
>
> I think the definition is wrong. memberof_group and some other fields
> should be defined as optional and multivalued fields insteads. Even the
> field's label uses a plural form.
>
> What do you think?

Yes, the definition is wrong, but I don't think it's worth fixing, since 
you can't rely on a single-value param having a single value in the 
output for any other command and param anyway.

Honza

-- 
Jan Cholasta