Re: [Fab-user] Simplification of contains?

[Jorge Vargas]

Awesome thank.

I should have try the contains stuff. I really don't know why I didn't :)

the hide function seems really nice I didn't saw that until now.

On Thu, May 28, 2009 at 8:14 PM, Jeff Forcier <address@hidden> wrote:
> On Thu, May 28, 2009 at 7:13 PM, Jorge Vargas <address@hidden> wrote:
>> I can't seem to find a way to simplify this, it looks to ugly for me.
>>
>> I basically need to know if env.domain is in a or b file and if it
>> isn't put it in b and recreate C
>>
>>    with settings(warn_only=True):
>>        check1 = contains(env.domain,'/etc/check1',exact=True)
>>        if check1.failed:
>>            check2 = contains(env.domain,'/etc/check2',exact=True):
>>            if check2.failed:
>>                append("%(domain)s" % env,'/etc/check2')
>>                run('regenerate_config /etc/check3')
>>
>> As a related note, is there a simple way to provide a different
>> message to contains (which call run, which calls abort) I'll like to
>> have a "custom abort message, instead of the failed command something
>> more human like. "This server failed check X"
>
> Two things:
>
> 1. contains() uses grep, which returns the empty string when the input
> isn't found, and since empty string evaluates to False in Python, it's
> simplest/best to simply treat contains() as returning a boolean value.
> No need to explicitly store the return value and then check .failed.
> 2. My intention thus far has been that "custom" output should be
> handled by turning off Fabric's internal abort/warn messages, and
> printing your own messages. The former can (as of alpha3) be
> accomplished by using settings() to squash together warn_only=True and
> hide('everything') or at least hide('warnings').
>
> With just #1, you could save two or three lines, depending on your
> line-length and wrapping tastes::
>
>    with settings(warn_only=True):
>        if not (contains(env.domain, '/etc/check1', exact=True)
>            or contains(env.domain, '/etc/check2', exact=True)):
>                append("%(domain)s" % env,'/etc/check2')
>                run('regenerate_config /etc/check3')
>
> With #2 (assuming for now that you only want to print a message if *both*
> contains checks failed; easy enough to adapt otherwise) we use the ``hide``
> context manager and a simple print statement::
>
>    with settings(warn_only=True, hide('everything')):
>        if not (contains(env.domain, '/etc/check1', exact=True)
>            or contains(env.domain, '/etc/check2', exact=True)):
>                print("[%s] /etc/checkN not found in domain file,
> appending and regenerating" % env.host_string)
>                append("%(domain)s" % env,'/etc/check2')
>                run('regenerate_config /etc/check3')
>
> One thing I'd like to do is make that "fake host prefix" bit easier, as I find
> myself doing it a lot. Whether this is through a simple e.g. print_with_host
> function, or funky monkeying with sys.stdout (I prefer the former to the
> latter) I'm not sure yet. But having fabfile output easily associated
> with the current host seems like a good idea (as long as it can also
> be easily opted out of!)
>
> Best,
> Jeff
>