listening to a process in Perl.

[bcdixit]

Hello,
I have a perl script in which i need run some other perl script.
The way I am doing this is through the system command i.e. something like this.

while(<read script names from a file>)
{
system("$script");
}

now, what I want to do is on the screen (STDOUT), I want to display something like

running my_script1.pl..........done!
running my_script2.pl.....failed!

I believe that when the system() function is called in a Perl script, the control is handed over to the script that is called within the system function and control is handed over to the parent only when the script is completed

what i need is when the script my_script1.pl is executed, then my script should print those dots (....) on the terminal screen every 2 seconds until i get a status from pass/fail status from my_script1.pl (or my_script2.pl)


can anybody help me with this.?

thanks
bcd

 

[hungryhungryhippo]

Hi, i once had a similar problem. maybe this will help:

http://www.tek-tips.com/viewthread.cfm?qid=1420124&page=1

Another option could be to fork the system calls. i think you could also jerry-rig a workaround by appending "&" to the command, which starts a new process and returns control immediately, at least on linux-like environments.
cheers!
michael

 

[hungryhungryhippo]

btw...on windows running active perl you may want to check out Win32:rocess (if i remember the name correctly)

 

[bcdixit]

sorry , I did not mention this earlier but this is on unix.

 

[MillerH]

The following solution is inspired by a thread solved by Kirsle: concurrent processes. from 1 May 07.

[gray][i]# name: scratch.pl[/i][/gray]

[url=http://perldoc.perl.org/functions/use.html][black][b]use[/b][/black][/url] [green]Time::HiRes[/green] [red]qw([/red][purple]sleep gettimeofday[/purple][red])[/red][red];[/red]
[black][b]use[/b][/black] [green]threads[/green][red];[/red]
[black][b]use[/b][/black] [green]threads::shared[/green][red];[/red]

[gray][i]# Constants[/i][/gray]
[url=http://perldoc.perl.org/functions/my.html][black][b]my[/b][/black][/url] [blue]$timer_delta[/blue] = [fuchsia]1[/fuchsia][red];[/red] [gray][i]# in Seconds[/i][/gray]
[black][b]my[/b][/black] [blue]@commands[/blue] = [red]([/red]
	[red]'[/red][purple]perl pause.pl 5[/purple][red]'[/red],
	[red]'[/red][purple]perl pause.pl 3[/purple][red]'[/red],
	[red]'[/red][purple]perl pause.pl 6[/purple][red]'[/red],
[red])[/red][red];[/red]

[blue]$|[/blue] = [fuchsia]1[/fuchsia][red];[/red] [gray][i]# Unbuffer STDOUT[/i][/gray]

[olive][b]foreach[/b][/olive] [black][b]my[/b][/black] [blue]$command[/blue] [red]([/red][blue]@commands[/blue][red])[/red] [red]{[/red]
	[url=http://perldoc.perl.org/functions/print.html][black][b]print[/b][/black][/url] [red]"[/red][purple]Running '[blue]$command[/blue]' [/purple][red]"[/red][red];[/red]
	
	[black][b]my[/b][/black] [blue]$running[/blue] : shared = [fuchsia]1[/fuchsia][red];[/red]
	[black][b]my[/b][/black] [blue]$timer_thr[/blue] = threads->[maroon]new[/maroon] [red]([/red][url=http://perldoc.perl.org/functions/sub.html][black][b]sub[/b][/black][/url] [red]{[/red]
		[black][b]my[/b][/black] [blue]$next[/blue] = gettimeofday[red];[/red]
		[olive][b]while[/b][/olive] [red]([/red][blue]$running[/blue][red])[/red] [red]{[/red]
			[blue]$next[/blue] += [blue]$timer_delta[/blue][red];[/red]
			[black][b]print[/b][/black] [red]"[/red][purple].[/purple][red]"[/red][red];[/red]
			[olive][b]while[/b][/olive] [red]([/red][blue]$running[/blue] && [blue]$next[/blue] > gettimeofday[red])[/red] [red]{[/red]
				[url=http://perldoc.perl.org/functions/sleep.html][black][b]sleep[/b][/black][/url][red]([/red][fuchsia].05[/fuchsia][red])[/red][red];[/red]
			[red]}[/red]
		[red]}[/red]
	[red]}[/red][red])[/red][red];[/red]

	[black][b]my[/b][/black] [blue]$process_thr[/blue] = threads->[maroon]new[/maroon] [red]([/red][black][b]sub[/b][/black] [red]{[/red]
		[url=http://perldoc.perl.org/functions/system.html][black][b]system[/b][/black][/url] [blue]$command[/blue][red];[/red]
		[blue]$running[/blue] = [fuchsia]0[/fuchsia][red];[/red]
	[red]}[/red][red])[/red][red];[/red]

	[gray][i]# rejoin the threads when they finish[/i][/gray]
	[blue]$process_thr[/blue]->[maroon]join[/maroon][red];[/red]
	[blue]$timer_thr[/blue]->[maroon]join[/maroon][red];[/red]

	[black][b]print[/b][/black] [red]"[/red][purple] done![purple][b]\n[/b][/purple][/purple][red]"[/red][red];[/red]
[red]}[/red]

[tt]------------------------------------------------------------
Pragmas (perl 5.8.8) used :
[ul]
[li]threads - Perl extension allowing use of interpreter based threads from perl[/li]
[li]threads::shared - Perl extension for sharing data structures between threads[/li]
[/ul]
Core (perl 5.8.8) Modules used :
[ul]
[li]Time::HiRes - High resolution alarm, sleep, gettimeofday, interval timers[/li]
[/ul]
[/tt]

[gray][i]# name: pause.pl[/i][/gray]

[url=http://perldoc.perl.org/functions/use.html][black][b]use[/b][/black][/url] [green]Time::HiRes[/green] [red]qw([/red][purple]sleep[/purple][red])[/red][red];[/red]

[url=http://perldoc.perl.org/functions/sleep.html][black][b]sleep[/b][/black][/url][red]([/red][url=http://perldoc.perl.org/functions/shift.html][black][b]shift[/b][/black][/url][red])[/red][red];[/red]

The output is the following:

>perl scratch.pl
Running 'perl pause.pl 5' ...... done!
Running 'perl pause.pl 3' .... done!
Running 'perl pause.pl 6' ....... done!

- Miller