[chef] Re: Re: Accessing Knife's return values within a script (without shelling out)

[Hedge Hog < >]

On Fri, Apr 15, 2011 at 12:58 AM, Daniel DeLeo 
<
 >
 wrote:
> On Thursday, April 14, 2011 at 5:22 AM, Hedge Hog wrote:
>
> Hi,
> Having got to run Knife commands from a script, without shelling out,
> all that remains is to be able to have whichever Knife method return
> the data from the show and list sub-commands.
> This too does not seem to be trivial, does anyone have any pointers,
> tips or tricks?
> Redirecting Knife's puts output is not trivial, Knife uses STDOUT
> throughout (tut, tut) rather than the recommended $stdout.
> The knife run method has output as its last method rather than
> returning the data :(
>
> Knife is an application and not a library. The difference is that knife is
> designed to print output to a terminal and will call Kernel#exit when it
> encounters an error. These are not behaviors you want in a library but they
> make knife much simpler to implement. If you want to use Chef from within a
> ruby program, you'll have a much easier time if you study the knife commands
> to see how to use Chef's library classes and then use those directly. That
> will give you complete flexibility to do whatever your application requires
> with the output, in case of error, etc.
> That said, using knife as a library might be okay for a quick and dirty
> hack. In Chef 0.10, almost all output from knife goes through a
> Knife::Core::UI object, which you can access via Knife#ui. UI objects allow
> you to assign objects to be used for stdin, stdout, and stderr.

Thanks Dan, I'll give that a try.

> --
> Dan DeLeo
>
>
> Appreciate any help.
>
> --
> πόλλ' οἶδ ἀλώπηξ, ἀλλ' ἐχῖνος ἓν μέγα
> [The fox knows many things, but the hedgehog knows one big thing.]
>   Archilochus, Greek poet (c. 680 BC – c. 645 BC)
> http://wiki.hedgehogshiatus.com
>
>



-- 
πόλλ' οἶδ ἀλώπηξ, ἀλλ' ἐχῖνος ἓν μέγα
[The fox knows many things, but the hedgehog knows one big thing.]
  Archilochus, Greek poet (c. 680 BC – c. 645 BC)
http://wiki.hedgehogshiatus.com