relation-get output is problematic

[Gustavo Niemeyer]

The command itself has a nice interface to handle that use case. YAML is
both readable and usable programmatically. That fits well in that situation.

gustavo @ http://niemeyer.net
On May 11, 2012 2:36 PM, "Benjamin Saller" <benjamin.saller at canonical.com>
wrote:

> While we certainly should improve the output to be something more
> uniform I don't think that YAML is the direction to push this. 'smart'
> when we originally talked about what it would do was to combine the
> properties of human readable with shell parseable. I'll agree that
> YAML is readable but its not easily shell parsable. That said I also
> agree the current output isn't exactly smart, to make it smarter we
> might take advantage of the following pseudo-code
>
> for item in result:
>     print >>stream, json.dumps(item)
>
> One item per line is easy for shell and items (Booleans for example)
> get a very standard JSON serialization which both golang and Python
> can easily produce and is easy to standardize around in shell.
>
> This pattern might have to be adapted slightly for some commands but
> the principal is one JSON serialized item per line, rather than
> dumping JSON arrays (which we can already do with --format json)
>
> -Ben
>
> On Wed, May 9, 2012 at 1:09 PM, Gustavo Niemeyer
> <gustavo.niemeyer at canonical.com> wrote:
> > Folks,
> >
> > I've been talking to William about this issue, and this was already
> > discussed live with some of you.
> >
> > We have an important bug to fix in relation-get and a few other
> > commands. Their output, somehow, ended up being *Python serialization*
> > rather than JSON or YAML, which is obviously wrong. It wasn't clear
> > that this was the case until very recently, when we introduced the
> > boolean types. That's made it obvious that this was the case because
> > one can see "True" (Python) instead of "true" (JSON/YAML) in the
> > output, but there are many other issues waiting to bite us seriously
> > (string formatting, for instance).
> >
> > My proposal is this:
> >
> > - Let's make the default output for everything structured be YAML
> > (e.g. relation-get -)
> > - Things like juju-log must not output *anything* (it is/was outputting
> {})
> >
> > Then, I'd also like to take the chance to propose an extension to
> > relation-get to help people that are getting out of the
> >
> >    if [ `relation-get some-bool` = True ]; then ...; fi
> >
> > situation, that actually makes the charm interface depend on
> > Python-specific value names, onto a much better version:
> >
> >    if relation-get --test some-bool; then ...; fi
> >
> > If people are happy with that, this change should be done ASAP in
> > juju-python, and proposed as an SRU so that we can get the charms
> > fixed and get us a proper runway for 12.04+ onwards. I'm happy to help
> > automating things somehow, if necessary, to avoid some of the pain.
> >
> > Comments?
> >
> > --
> > Gustavo Niemeyer
> >
> > --
> > Juju mailing list
> > Juju at lists.ubuntu.com
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> https://lists.ubuntu.com/mailman/listinfo/juju
>
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