Re: Time based processes

[punit jain]

Hi

Below is my script where alarm is generated after 15 sec and changes the
global variable in parent from 0 to 1. Is there any mistake in my
multiprocess approach with time-based stop ?

#!/usr/bin/perl
use strict;
use warnings;
use Parallel::ForkManager;

my $MAX_PROC=2;
$|++;
my $stopFlag=0;

main();

sub main {

preprocess(@ARGV);
multiproc($MAX_PROC, @ARGV);

}
sub multiproc {

my $proc=shift;
my $argu = $ARGV[0];

open(USRFILE, "$argu") or die "cant open $!";
    my $pmgr  = Parallel::ForkManager->new($proc);

        $pmgr->run_on_finish(
           sub { my ($pid, $exit_code, $ident) = @_;
           print "** $ident just got out of the pool ** with PID $pid and
parent pid as $$ exit code: $exit_code\n";
           }
         );
       $pmgr-> run_on_start(
           sub { my ($pid,$ident)=@_;
                 print "** $ident started, pid: $pid **\n";
               }
             );

    $SIG{ALRM} = sub { $stopFlag = 1; };
    alarm(16);

    while(my $user = <USRFILE>) {
    chomp($user);
    print "value of Stop Flag in parent $0 is $stopFlag\n";
    if($stopFlag == 1) {
    print "stop flag has been set\n";
    last;
    }
    my $id = $pmgr->start($user) and next;
    print "value of Stop Flag in child $id is $stopFlag\n";
            sleep(7);

    $pmgr->finish($user);
  }
    print "Waiting for all children to exit\n";
    $pmgr->wait_all_children();
    alarm(0);
    print "All children completed\n";
}


This is what I get output : -

perl mprocess.pl /tmp/list1
value of Stop Flag in parent mprocess.pl is 0
value of Stop Flag in child 0 is 0
** te...@test.com started, pid: 21777 **
value of Stop Flag in parent mprocess.pl is 0
value of Stop Flag in child 0 is 0
** te...@test.com started, pid: 21778 **
value of Stop Flag in parent mprocess.pl is 0
** te...@test.com just got out of the pool ** with PID 21777 and parent pid
as 21776 exit code: 0
** te...@test.com just got out of the pool ** with PID 21778 and parent pid
as 21776 exit code: 0
value of Stop Flag in child 0 is 0
** te...@test.com started, pid: 21811 **
value of Stop Flag in parent mprocess.pl is 0
value of Stop Flag in child 0 is 0
** te...@test.com started, pid: 21812 **
value of Stop Flag in parent mprocess.pl is 0
** te...@test.com just got out of the pool ** with PID 21811 and parent pid
as 21776 exit code: 0
** te...@test.com just got out of the pool ** with PID 21812 and parent pid
as 21776 exit code: 0
value of Stop Flag in child 0 is 0
** te...@test.com started, pid: 21832 **
value of Stop Flag in parent mprocess.pl is 0
value of Stop Flag in child 0 is 0
** te...@test.com started, pid: 21833 **
value of Stop Flag in parent mprocess.pl is 0
** te...@test.com just got out of the pool ** with PID 21832 and parent pid
as 21776 exit code: 0
** te...@test.com just got out of the pool ** with PID 21833 and parent pid
as 21776 exit code: 0
value of Stop Flag in child 0 is 1
** te...@test.com started, pid: 22030 **
value of Stop Flag in parent mprocess.pl is 1
stop flag has been set
Waiting for all children to exit
** te...@test.com just got out of the pool ** with PID 22030 and parent pid
as 21776 exit code: 0
All children completed

The only concern here is I see value of stopflag as 1 for child before the
parent which is a bit wierd:-

value of Stop Flag in child 0 is 1
** te...@test.com started, pid: 22030 **
value of Stop Flag in parent mprocess.pl is 1

Thanks and Regards.