use strict;
use warnings;
use File::Temp ();
use POSIX ":sys_wait_h";

my $app = sub {
    my $temp = File::Temp->new(UNLINK => 0);
    my $filename = $temp->filename;

    my $pid = fork();

    defined $pid  or  return [
        500,
        ["Content-type" => 'text/plain'],
        ["Could not fork: $!"]
    ];
    if ($pid) {
        # parent process: reap children which are done,
        # then print response and return
        my $kid;
        do {
            $kid = waitpid(-1, WNOHANG);
        } while $kid < -1;

        return [
            200,
            ["Content-type" => 'text/plain'],
            ["Started process with pid '$pid'\n",
             "Printing to '$filename'\n",
            ],
        ];
    }
    else {
        # child process: take 10 seconds to print, then exit
        my $count = 1;
        while ($count < 10) {
            print $temp $count++,"\n";
            sleep 1;
        }
        close $temp;
        exit 0;
    }
}