Hi Punit,
a few comments on your code.
On Thu, 26 Jul 2012 10:17:13 +0530
punit jain <contactpunitj...@gmail.com> wrote:
> 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;
It's good that you're using "strict" and "warnings", but you lack more empty
lines between paragraphs in your code.
>
> my $MAX_PROC=2;
> $|++;
> my $stopFlag=0;
You should use IO::Handle->autoflush(1) instead of $|++ for clarity.
>
> main();
>
> sub main {
>
> preprocess(@ARGV);
> multiproc($MAX_PROC, @ARGV);
>
> }
Your indentation is bad. Where is preprocess() defined? Moreover, I should note
that passing @ARGV directly to subroutine smells of lack of separation of
concerns.
> sub multiproc {
>
> my $proc=shift;
Your indentation is bad and you need spaces surrounding the "=".
> my $argu = $ARGV[0];
Don't use $ARGV[0] directly:
http://perl-begin.org/tutorials/bad-elements/#subroutine-arguments
>
> open(USRFILE, "$argu") or die "cant open $!";
1. Don't use bareword file handles.
2. Use three-args opens.
3. Don't surround strings with quotations.
See:
* http://perl-begin.org/tutorials/bad-elements/#vars_in_quotes
* http://perl-begin.org/tutorials/bad-elements/#open-function-style
You also should use a more descriptive and cohernet name than USRFILE and also
see:
http://perl-begin.org/tutorials/bad-elements/#calling-variables-file
> my $pmgr = Parallel::ForkManager->new($
> proc);
>
> $pmgr->run_on_finish(
> sub { my ($pid, $exit_code, $ident) = @_;
Don't put the argument unpacking on the same line as the "{".
> 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)=@_;
Again, and you have a space after the "->".
> 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;
> }
Just use if ($stopFlag) here.
> 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";
Again - bad indentation.
Regards,
Shlomi Fish
> $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 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.
--
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