in reply to launch long running background program and watch final progress
Well, I was waiting around and working on another part of the code when it hit me. I am still not sure how to do what I want the "right" way (assuming there is such a thing). But I came up with what I think is a pretty reasonable solution:
I redirected STDOUT and STDERR to a file when I run the application. Once the file is created, I use File::Tail to watch the file for the telltale string letting me the database is ready to accept connections and break out of the while loop that File::Tail is conveniently allowing me to use to block with. Here is the working code if anyone happens to ever have a similar problem
Or maybe I am the only knuckle dragger that has never run into this kind of issue before and solved it a long time ago?
sub cge_start { my($arg_ref) = @_; #=+ iterate over provided config and replace defaults while(my($k,$v) = each %$arg_ref) { #=+ Replace each default value if the key exists. Perhaps paranoi +d, but prevent arbitrary/unexpected settings $arguments{$k} = $v if exists $arguments{$k}; } #=+ Make sure we have a bare minimum of settings return undef if $arguments{dataDir} eq '' || !-d $arguments{dataDir} + || $arguments{imagesPerNode} eq '' || $arguments{nodeCount} eq ''; #=+ Create the results directory # make sure that our directory has a trailing slash "/" $arguments{dataDir} .= '/' unless $arguments{dataDir} =~ m/\/$/; #=+ Create the results directory if it does not exist mkdir $arguments{dataDir}.'results', 0744 if !-d $arguments{dataDir} +.'results'; $arguments{resultDir} = $arguments{dataDir}.'results'; #=+ Create a temporary directory to store all the junk files we crea +te for easy cleanup later mkdir $arguments{dataDir}.'temp', 0744 if !-d $arguments{dataDir}.'t +emp'; #=+ Create the logfile string (does not need to exist) $arguments{logFile} = $arguments{dataDir}.'cge_logfile.log'; #=+ Make sure we have both the number of instances and number of des +ired nodes return (undef,undef) unless $arguments{imagesPerNode} > 0 && $argume +nts{nodeCount} > 0; #=+ Create a cleanup script that we will use to kill "this" server s +ession $arguments{cleanupScript} = $arguments{dataDir}.'temp/cleanup.sh'; #=+ Make sure we have a free TCP port to use my $port = 3750; if(check_port($port)) { $port++; while(check_port($port)) { $port++; } } $arguments{queryPort} = $port; #=+ Concatenate all the non-blank command line arguments my @args; while(my($k,$v) = each %arguments) { push @args, '--'.$k.' '.$v.' ' unless $v eq ''; } my $arg_string = join('',@args); #=+ Run the launcher #exec($cge_launch.' '.$arg_string.'> /dev/null 2>&1 &'); my $success = run(command => $cge_launch.' '.$arg_string.' > '.$argu +ments{dataDir}.'temp/stdout.txt 2>&1 &', verbose => 0); #=+ Something went wrong, so just return undef return (undef,undef) unless $success; my $file = File::Tail->new($arguments{dataDir}.'temp/stdout.txt'); while(my $line = $file->read) { last if $line =~ m/Starting port forwarding/; } open(my $CU,'<',$arguments{cleanupScript}) or croak $!; my $text = <$CU>; close($CU); my $pid; if($text =~ m/scancel (\d+)/m) { $pid = $1; } return ($pid,$port); }
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Re^2: launch long running background program and watch final progress
by Marshall (Canon) on Apr 22, 2016 at 16:30 UTC | |
by Anonymous Monk on Apr 22, 2016 at 19:29 UTC | |
by Marshall (Canon) on Apr 22, 2016 at 20:02 UTC | |
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Re^2: launch long running background program and watch final progress
by Anonymous Monk on Apr 22, 2016 at 20:46 UTC | |
by Anonymous Monk on Apr 22, 2016 at 20:49 UTC | |
by Marshall (Canon) on Apr 22, 2016 at 21:58 UTC |