[Freeipa-devel] freeIPA v2: Changes to output_for_cli() signature

[Simo Sorce]

On Sun, 2008-11-16 at 21:41 -0700, Jason Gerard DeRose wrote:
> The output_for_cli() method signature has changed from:
> 
>   output_for_cli(self, result)
> 
> to:
> 
>   output_for_cli(self, textui, result, *args, **options)
> 
> Rob had the excellent idea of passing the args and options the command
> was called with (thus the new *args, **options in the signature).
> 
> I've been thinking about how output should be formatted when a command
> is called through the CLI, and my conclusion was that we really don't
> want commands using the print statement directly... we want the commands
> to provide a consistent experience to the user, and that's too difficult
> to do if every command does its own output totally willy-nilly.
> 
> So I started work on a new "textui" backend plugin. The goal is to
> provide maybe a dozen or so high-level methods for common output
> scenarios, and then have each command's output_for_cli() method use only
> this textui API. This way we can tweak the CLI output by just modifying
> the textui plugin, but have it affect all the commands simultaneously.
> This textui plugin will also do things like determine the tty width and
> word wrap appropriately.
> 
> The textui plugin is in ipalib/cli.py
> 
> The best examples so far of using textui are probably the "env" and
> "plugins" commands in ipalib/plugins/f_misc.py
> 
> I also added two related sections in the tutorial.  I still haven't
> figured out how to make epydoc include anchors, but the two new sections
> are named:
> 
>   "Allowed return values from your command"
> 
> and
> 
>   "How your command should print to stdout"
> 
> They are about half way down the page. As always, the latest build of
> the tutorial can be found here:
> 
>   http://freeipa.org/developer-docs/ipalib-module.html
> 

This is an excellent idea!
It is indeed fundamental that we do not do any printing directly, but
let application developers choose how to mange the output.

Thanks,
Simo.

-- 
Simo Sorce * Red Hat, Inc * New York