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Re: Best practice ipc and Log::Log4perl

by starbolin (Hermit)
on Jul 04, 2008 at 04:32 UTC ( #695512=note: print w/replies, xml ) Need Help??


in reply to Best practice ipc and Log::Log4perl

Could you be more specific as to what you want to do that IPC::Open3, IPC::Run3, Tie::STDOUT, Tie::STDERR don't do? I don't understand.


s//----->\t/;$~="JAPH";s//\r<$~~/;{s|~$~-|-~$~|||s |-$~~|$~~-|||s,<$~~,<~$~,,s,~$~>,$~~>,, $|=1,select$,,$,,$,,1e-1;print;redo}

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Re^2: Best practice ipc and Log::Log4perl
by codeacrobat (Chaplain) on Jul 04, 2008 at 12:37 UTC
    What I want:
  • read unbuffered from a child process ( long running process ).
  • capture childprocess stderr & stdout separately
  • write the childprocess stdout and stderr stream to a logfile and tag lines with a <timestamp> and a tag <INFO> or <ERROR> depending on the source stream.
  • IPC::Run3 almost does what I need.
    #!/usr/bin/perl # timestamp.pl $|++; while(time - $^T<10){ select undef,undef,undef, 0.1; if ( rand()<0.5) { print STDERR time(), " warn\n"; } else { print time(), " info\n"; } } __END__
    use IPC::Run3 qw(run3); my @cmd = ('perl', 'timestamp.pl'); run3 \@cmd, undef, \&out, \&err; sub out { print time(), " out: $_\n"; } sub err { print time(), " err: $_\n"; } __END__ # The problem is that run3 buffers the output. 1215162770 out: 1215162760 info 1215162770 out: 1215162760 info 1215162770 out: 1215162761 info 1215162770 out: 1215162761 info 1215162770 out: 1215162761 info 1215162770 out: 1215162761 info 1215162770 out: 1215162762 info 1215162770 out: 1215162762 info 1215162770 out: 1215162762 info 1215162770 out: 1215162763 info

    print+qq(\L@{[ref\&@]}@{['@'x7^'!#2/"!4']});

      Run3 apparently doesn't do concurrency. IPC:Run can be made to do what you want. This works:

      #!/usr/bin/perl # timestamp.pl while(time - $^T<10){ select undef,undef,undef, 0.1; if ( rand()<0.5) { print STDERR time(), " warn\n"; } else { print time(), " info\n"; } } print "end\n"; __END__ use IPC::Run qw ( start pump finish timeout ); my $in; my $out; my @cmd = qw( perl timestamp.pl); ## Build the harness, open all pipes, and launch the subprocesses my $h = start \@cmd, \$in, \$out, \$out ; $in = "" ; ## Now do I/O. start() does no I/O. pump $h while length $in ; ## Wait for all input to go ## Now do some more I/O. while (1){ pump $h until $out =~ s/(.+)\n$//gm ; last if ("end" eq $1); print time, " : $1\n"; } ## Clean up finish $h or die "cat returned $?" ; __END__ 1215226647 : 1215226647 info 1215226647 : 1215226647 info 1215226647 : 1215226647 warn 1215226647 : 1215226647 info 1215226647 : 1215226647 warn 1215226647 : 1215226647 warn 1215226647 : 1215226647 info 1215226647 : 1215226647 info 1215226647 : 1215226647 info 1215226648 : 1215226648 warn


      s//----->\t/;$~="JAPH";s//\r<$~~/;{s|~$~-|-~$~|||s |-$~~|$~~-|||s,<$~~,<~$~,,s,~$~>,$~~>,, $|=1,select$,,$,,$,,1e-1;print;redo}
        Thanks for your solution IPC::Run is probably the best way to go. If you set $|++ in timestamp.pl we have it.
        perl -MIPC::Run=run -e ' run( [ "perl", "timestamp.pl" ], "1>", sub { print "out " . time() . " " , @_ }, "2>", sub { print "err ". time() . " " , @_} ) ' out 1215247029 1215247029 info err 1215247029 1215247029 warn err 1215247029 1215247029 warn out 1215247029 1215247029 info err 1215247029 1215247029 warn err 1215247029 1215247029 warn out 1215247030 1215247030 info err 1215247030 1215247030 warn err 1215247030 1215247030 warn err 1215247030 1215247030 warn err 1215247030 1215247030 warn out 1215247030 1215247030 info err 1215247030 1215247030 warn out 1215247030 1215247030 info out 1215247030 1215247030 info out 1215247031 1215247030 info out 1215247031 1215247031 info err 1215247031 1215247031 warn err 1215247031 1215247031 warn out 1215247031 1215247031 info err 1215247031 1215247031 warn out 1215247031 1215247031 info out 1215247031 1215247031 info err 1215247031 1215247031 warn err 1215247031 1215247031 warn

        print+qq(\L@{[ref\&@]}@{['@'x7^'!#2/"!4']});

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