#!/usr/bin/perl -w
#
# $Id: logmirror,v 1.9 2004/02/05 17:47:31 nugget Exp $
# (c) Copyright 2004 David C. McNett.  All Rights Reserved.
#
# Author:          David McNett <nugget@slacker.com>
# Current Version: http://www.slacker.com/~nugget/stuff/logmirror
#
# logmirror daemon -- this will mirror remote logfiles to local files in a
# bandwidth-friendly manner.  This allows you to monitor those logfiles with
# native OSX tools such as the "Logger" widget by Todd Harris for Konfabulator.
#
# Logger widget is here: http://www.widgetgallery.com/view.php?widget=26399
#
# This script assumes that you have ssh working with public key auth and that
# your SSH_AUTH_SOCKET is available to jobs run from crontab.  If you use 
# SSHKeyChain by Bart Matthaei, this should work without any additional 
# tweaks.
#
# SSHKeyChain is here: http://www.sshkeychain.org/
#
# First, edit this @logs array to contain one or more remote logs which
# you want to mirror locally.  Each line is in the format:
#
#  {remote hostname or ip}:{command to run on remote host}:{local filename}

my @logs = (
     'dazed.slacker.com:weblog:/tmp/dazed_access_log',
     'dazed.slacker.com:tail -f /var/log/messages:/tmp/dazed_messages',
);

# Once you've edited the above, edit your personal crontab to run this script
# periodically.  I run it every minute with the line:
#
#  */1 * * * * /Users/nugget/bin/logmirror
#
# You can edit your crontab with the command "crontab -e"
# 
# The script attempts to be as smart as possible, not trying to spawn 
# the mirroring if no networks are available (common with roaming laptops).
#
# There are a few configuration setting you may wish to tweak:

my $control_widget = 0;  # Setting this to 1 will cause the script to start
                         # and stop the Logger widget in coordination with 
                         # the mirroring of remote logfiles.  Set this to 0
                         # to disable this control.

# The $widget variable should store the command which will be run to restart
# the widget if $control_widget is set to 1.  The setting below will work if
# you have installed the widget to the default location:

my $login = `whoami`;  chomp $login;
my $widget = "/Applications/Konfabulator.app/Contents/MacOS/Konfabulator /Users/$login/Documents/Widgets/Logger.widget --child &";

#
# You shouldn't have to edit anything below this point
#

$ENV{'PATH'} = '/bin:/usr/bin:/usr/local/bin:/sbin:/usr/sbin:/usr/local/sbin';
$ENV{'BASH_ENV'} = '';

use strict;
use Sys::Syslog;

sub debug {
    my ($level,$buf) = @_;

    # print "$buf" . "\n";
    Sys::Syslog::syslog($level,$buf);
}

Sys::Syslog::openlog('logmirror','pid','daemon');
Sys::Syslog::setlogsock('unix');

my $nethash = `ifconfig | grep inet | md5`; chomp $nethash;
my $lasthash = `cat /tmp/nethash`; chomp $lasthash;

if($nethash ne $lasthash) {
    debug('notice',"Network configuration has changed, recycling mirrors.");
    open PROCS, 'ps auxwww | egrep "([s]sh -natt)" |';
    while(<PROCS>) {
        debug('debug',$_);
        if($_ =~ /^([^ ]+) +(\d+)/) {
            debug('notice',"Killing Process $2");
            system "kill -TERM $2";
        }
    }
    close PROCS;
    system "echo $nethash > /tmp/nethash";
}
my $uid = int `id -u`;
if(!($ENV{'SSH_AUTH_SOCK'})) {
    debug('debug',"No SSH_AUTH_SOCK, assuming SSHKeychain value.");
    $ENV{'SSH_AUTH_SOCK'} = "/tmp/$uid/SSHKeychain.socket";
}

my $netactive = int `ifconfig | grep -c "status: active"`;
if($netactive == 0) {
    debug('info',"No networks are active.");
    if($control_widget == 1) {
      open PROCS, 'ps auxwww | egrep "([s]sh -natt |[L]ogger.widget)" |';
    } else {
      open PROCS, 'ps auxwww | egrep "([s]sh -natt)" |';
    }
    while(<PROCS>) {
        debug('notice',$_);
        if($_ =~ /^([^ ]+)  (\d+)/) {
            debug('notice',"Killing Process $2");
            system "kill -TERM $2";
        }
    }
    close PROCS;
} else {
    debug('debug',"Looking for logs to mirror");
    my $widget_running = int `ps auxwww | egrep -c "[L]ogger.widget"`;
    if($control_widget == 1) {
        if($widget_running != 1) {
            debug('debug',"Logger.widget is not running");
            system $widget;
        }
    }
    debug('debug',"Logger.widget is running");
    foreach my $log (@logs) {
        my ($host, $command, $destfile) = split /:/, $log;
        debug('debug',"Evaluating $host:$command for mirroring");

        my $isrunning = int `ps auxwww | egrep -c "[s]sh -natt $host.*$command"`;
        if($isrunning == 0) {
            debug('debug',"No existing tail running for $host:$command");
            if(`ping -c 1 $host`) {
                 debug('notice',"I can reach $host and mirroring is currently off for $command.  Launching an ssh tail now.");
                 system "ssh -natt $host \"$command\" > $destfile & # logmirror";
            } else {
                 debug('info',"Unable to ping $host.  No mirroring is possible at this time.");
            }
        }
    }
}