/perl/dklab_realplexor.pl

#!/usr/bin/perl -w
#@
#@ Dklab Realplexor: Comet server which handles 1000000+ parallel browser connections
#@ Author: Dmitry Koterov, dkLab (C)
#@ GitHub: http://github.com/DmitryKoterov/
#@ Homepage: http://dklab.ru/lib/dklab_realplexor/
#@

use strict;
BEGIN {
    if (!eval('use EV; 1')) {
        print STDERR "Error: EV library is not found in your system:\n";
        print STDERR "http://search.cpan.org/~mlehmann/EV-3.9/EV.pm\n";
        print STDERR "You must install EV, e.g.:\n";
        print STDERR "# yum install gcc\n";
        print STDERR "# perl -MCPAN -e \"install EV\"\n";
        print STDERR "  - or -\n";
        print STDERR "# apt-get install gcc\n";
        print STDERR "# perl -MCPAN -e \"install EV\"\n";
        exit(1);
    }
}

use File::Basename;
use lib dirname(__FILE__);
use Storage::DataToSend;
use Storage::ConnectedFhs;
use Storage::OnlineTimers;
use Storage::PairsByFhs;
use Realplexor::Event::Connection;
use Realplexor::Event::Server;
use Connection::Wait;
use Connection::In;
use Realplexor::Config;
use Realplexor::Common;
use Getopt::Long;
use Realplexor::Event::Signal;


# Main processing loop.
sub mainloop {
    my $ulimit = `/bin/sh -c "ulimit -n"`; chomp $ulimit;
    Realplexor::Common::logger("Starting. Opened files limit (ulimit -n): $ulimit.");

    # Load configs.
    my $additional_conf = $ARGV[0];
    Realplexor::Config::load($additional_conf);

    # Turn on STDOUT buffering in non-verbose mode.
    $| = 0 if $CONFIG{VERBOSITY} < 3;

    # Initialize servers.
    my $wait = Realplexor::Event::Server->new(
        name => "WAIT",
        listen => $CONFIG{WAIT_ADDR},
        timeout => $CONFIG{WAIT_TIMEOUT},
        connectionclass => "Connection::Wait",
        logger => \&Realplexor::Common::logger,
    );

    my $in = Realplexor::Event::Server->new(
        name => "IN",
        listen => $CONFIG{IN_ADDR},
        timeout => 0, #$CONFIG{IN_TIMEOUT},
        connectionclass => "Connection::In",
        logger => \&Realplexor::Common::logger,
    );

    # Catch signals.
    use POSIX qw(SIGHUP SIGINT SIGPIPE);
    Realplexor::Event::Signal::create(SIGHUP, sub {
        Realplexor::Common::logger("SIGHUP received, reloading the config");
        my $low_level_opt = Realplexor::Config::reload($additional_conf);
        if ($low_level_opt) {
            Realplexor::Common::logger("Low-level option $low_level_opt is changed, restarting the script from scratch");
            exit();
        }
        return;
    });
    Realplexor::Event::Signal::create(SIGINT, sub {
        Realplexor::Common::logger("SIGINT received, exiting");
        exit();
    });
    Realplexor::Event::Signal::create(SIGPIPE, sub {
        Realplexor::Common::logger("SIGPIPE ignored");
        return 0;
    });

    # If running as root, SU to safe user.
    my $user = $CONFIG{SU_USER};
    if (!$> && $user) {
        my ($implemented,$name,$passwd,$uid,$gid,$quota,$comment,$gcos,$dir,$shell,$expire) = eval { (1, getpwnam($user)) };
        if ($implemented) {
            die "User $user is not found\n" if !defined $name;
            Realplexor::Common::logger("Switching current user to unprivileged \"$user\"");
            $) = $gid; $( = $gid;
            $> = $uid; $< = $uid;
        }
    }

    Realplexor::Event::Server::mainloop();
}

# Re-run self with high ulimit.
Realplexor::Tools::rerun_unlimited();
$0 = "dklab_realplexor";  # for killall in smoke tests

# Chdir to script's directory.
use FindBin qw($Bin);
chdir($Bin);

# Turn off buffering in debug log. (Load test says that there is
# no difference in performance if bufferring is turned off or not.)
$| = 1;

# Turn on zombie auto-reaper.
$SIG{CHLD} = 'IGNORE';

# Handle all signals to call END{} block at the end.
use sigtrap qw(die untrapped normal-signals);

# Parse command-line args.
my @save_argv = @ARGV;
my $pid_file;
GetOptions("p=s" => \$pid_file);

# Load config: it is also needed by parent watchdog.
my $additional_conf = $ARGV[0];
Realplexor::Config::load($additional_conf, 1);

# Save PID?
if ($pid_file) {
    open(local *F, ">", $pid_file) or die "Cannot create $pid_file: $!\n";
    print F $$;
    close(F);
}

# Child PID.
my $pid;

# Run watchdog loop.
while (1) {
    delete $SIG{HUP};
    $pid = fork();

    if (!defined $pid) {
        # Fork failed.
        Realplexor::Common::logger("fork() failed: $!");
    } elsif (!$pid) {
        # Child process.
        eval {
            @ARGV = @save_argv; # because GetOptions() modifies ARGV
            mainloop();
        };
        die $@ if $@;
        exit();
    }

    # Pass SIGHUP to children.
    $SIG{HUP} = sub {
        kill 1, $pid;
    };

    # Waid for child termination.
    Realplexor::Tools::wait_pid_with_memory_limit($pid, $CONFIG{MAX_MEM_MB});
    sleep(1);
}

# Called if process dies.
END {
    return if !$pid; # children
    Realplexor::Tools::graceful_kill($pid, $pid_file);
}