in reply to Re^2: Win32::Process output
in thread Win32::Process output

Try this (from a couple of posts down from the link I provided at:633867): 

#! perl -slw
use strict;

sub timedCommand {
    use threads;
    use threads::shared;
    my( $cmd, $timeout ) = @_;

    my @results :shared;
    my $pid :shared;

    async {
        $pid = open my $fh, "$cmd |" or die "$!, $^E";
        @results = <$fh>;
    }->detach;

    kill 0, $pid while sleep 1 and $timeout--;
    kill 3, $pid and return if $timeout;
    return @results;
}

...
 ## Run foo.exe, kill it after 20 seconds.
my @results = timedCommand( 'foo.exe -opt', 20 );
...

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Re^4: Win32::Process output
by Anonymous Monk on Nov 03, 2010 at 22:36 UTC

    I think I (somewhat) understand now. The async {} is some sort of inline function definition? I could do the same thing by separating out that part into a sub and then calling the threads->new() function with a reference to the sub?

    Since this uses threading anyway, would there be a way to e.g. run some set number of threads (say 20) at a time and kill them if they lasted longer than a timeout period? If you killed a process being run from inside a thread, would the thread terminate? Or does the thread->kill() function successfully terminate the process and the thread simultaneously?

[reply]

      Let me see if I understand you correctly.

      • You have a whole bunch of commands (more than 20) that you want to run concurrently, but never more than 20 at a time.
      • You want to gather the output from those commands.
      • If they do not complete within some specified time, you want to terminate them.
      • If they do not complete, you aren't interested in any output they may have produced before being killed.
      • The program is already using thread for other things.

      A few questions:

      • Do the other threads in the program count towards your limit of 20? Or does that limit only apply to concurrent comamnds?
      • Are these commands the same executable with different parameters? If so, my I ask what executable?
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

        Pretty much and much more succinct, except by 'already using threads' i meant that the solution seems to be using threads (as per your demonstration). Originally I was just going to run each executable one at a time and I'm pretty sure I could do that in the way you've explained, but I think it would be possible to speed up the process with threads. 20 was just a guesstimate, and really what I need is 'run the number of simultaneous threads that won't make my little laptop choke and die'

        I have anywhere from 1000 to 5000 (ballpark) commands to run. Each is the same command just with a different workstation name passed as a command line option each time. The application itself doesn't provide any sort of facility that i know of for passing multiple hostnames at once and the timeout option it provides doesn't actually work.

        The executable is marimba's runchannel.exe and the result is one of: 1) timeout (check with Net::Ping prior to trying and I'm assured ICMP doesn't bounce anywhere) 2) Success 3) Successful Connection, Operation Unnecessary 4) Unable to connect 5) Completely hang and never respond. I need to be able to report the first 4 results along with the workstation name, and the small number that fall into #5 I can safely ignore for the time being, but those are the ones that are causing me difficulties to script because they never return (and I've run this from commandline manually and using another tool and the same thing happens). I was able to run this once using Win32::Process->Wait() but all of the output went to stdout and I couldn't find a way to log it with the workstation name (i.e. if i change the process to cmd /c foo.exe all it outputs to file is a list without the workstation names)

[reply]

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