how to convert shell captures into anyevent style?

[Fulko Hew]

On Thu, Mar 29, 2012 at 1:27 PM, Darin McBride <darin.mcbride at shaw.ca>
wrote:
>
> On Thursday March 29 2012 6:48:09 PM Zsbán Ambrus wrote:
> > On 3/29/12, Fulko Hew <fulko.hew at gmail.com> wrote:
> > >     foreach (`prog|prog|prog`) {
> > >
> > > What I obviously need to do is to turn my obtainer() into an event
driven
> > > aspect too!  And I think what I want is an 'IO Watcher', but...
> >
> > Take a look at the run_cmd function in the AnyEvent::Util module.  It
> > spawns you a program (in this case you'll ask it spawn a shell so it
> > interprets all those inner pipe to you) and handles reading its
> > output.  When it's finished, split the output to lines.
>
> If you really want to go all the way with AE here, making it entirely
> asynchronous, run_cmd is still the right way, but you can set some
callbacks
> for stdout and stderr such that you get the lines as they come in.


I tried that (I thought correctly, as per below) and I get an error rather
than my callback being called.
Its probably something stupid, but I'm not seeing it...
(And I can't find any examples in the AnyEvent::Util module or its test
directory.)

Not a GLOB reference at /usr/lib/perl5/site_perl/5.8.8/AnyEvent/Util.pm
line 592.
where the code looks like:

        if (defined eval { fileno $ob }) {

my snippet is:

sub collector {
    my ($x) = @_;

    print "collector got: $x\n";
}

$::cv = run_cmd "echo \"display chstatus (*)\" | runmqsc $mgrName",
                    ">" => \&collector;

>  I see
> nothing in the docs that say, however, that you're guaranteed to get full
> lines, though, in general, assuming short enough lines, that's what I've
been
> seeing in my own usage.  That may, however, be an artefact of how my
> subprograms produce their output (they may flush on line breaks, which is
a
> reasonable default for stderr).

I got that too, that's why I'm testing what's (going to) happen with the
example above.

> I have code that accumulates the output into a separate buffer, splits
that on
> line breaks, sends it on to the code that is interested, but keeps partial
> lines hidden away in the buffer for the next callback, so that the
business-
> logic code never sees a partial line, which greatly simplifies that code.

Would you share that with me?

> Personally, I've done the same thing with IO::Select and IPC::Open3.
> AnyEvent::Util::run_cmd is FAR simpler to use, and to get right.
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