Based on the description of your requirement, it sounds like you will need to fork two children - one to check the server, one to do the countdown. Something like this:
use strict;
use warnings;
use feature qw(:5.10);
# Fork off two child processes
my ($who_am_i, $countdown_pid, $checking_pid);
$countdown_pid = fork();
if ($countdown_pid == 0){
$who_am_i = "countdown process";
} elsif ($countdown_pid){
$checking_pid = fork();
if ($checking_pid == 0){
$who_am_i = "checking process";
} elsif ($checking_pid){
$who_am_i = "controlling process";
} else{
die "Error forking: $!";
}
} else{
die "Error forking: $!";
}
# Each process does different things:
given($who_am_i){
when ("countdown process"){
sleep_count(3, 'Verifying with Nagios that resin is down: ');
}
when ("checking process"){
# repeatedly do server check via "nagios"
}
when ("controlling process"){
# Wait on the "checking process" to complete.
waitpid($checking_pid, 0);
# Kill countdown timer
kill("TERM", $countdown_pid);
waitpid($countdown_pid, 0);
}
}
You should probably check the exit status of your child processes (via $? after the waitpid calls).
Hope this helps.
Update: Actually, there's no need to have three processes. Two is enough, as in your post, although conceptually I like the idea of delegating each subtask to separate child processes.
Perhaps the only piece that was really missing from your code was killing off the countdown timer.
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