#!/usr/bin/perl

# 10/2002 V. Blum, NREL
# Replacement for MAPS's original chl command to work on current Scyld Beowulf etc.
# In case of problems with this version of chl, the old version is called chl.csh

if ($ARGV[0]) 
{
  if ($ARGV[0] =~ "-h" )
  {
      print "chl [-m alternative_machine_config_file]\n";
      print "Checks the load on the remote machines specified in the ~/.machines.rc file\n";
      print "or as overridden by the -m option\n";
      print "The first column of output is the load and the commands following the + sign\n";
      print "give the command prefix needed to run on that machine\n";
      print "A default ~/.machines.rc is created the first time the command is run.\n";
      print "See comments therein for the format of the file.\n";
      exit;
  }
  if ($ARGV[0] =~ "-m" )
  {
    $machinefile = $ARGV[1] ;
  }
}
else
{
  $machinefile = "$ENV{HOME}/.machines.rc" ;
}

if (! -e $machinefile )
{
  print "Unable to read machine description $machinefile.\n" ;
  if (-e "$ENV{HOME}/.machines.rc" )
  {
    print "Resorting to $ENV{HOME}/.machines.rc.\n" ;
    $machinefile = "$ENV{HOME}/.machines.rc" ;
  }
  else
  {
    print "Creating $ENV{HOME}/.machines.rc ... \n" ;
    print "Please edit this file to reflect your machine setup.\n" ;

    open (MF,">$ENV{HOME}/.machines.rc") ;
    print MF "#configuration file for chl, minload, and pollmach\n";
    print MF "#this line indicates the waiting time between the checks of machine availability\n";
    print MF "#in seconds\n";
    print MF "set waitbetweenpoll=60\n";
    print MF "#The remainder of this file lists the machines\n";
    print MF "#columns in this file are separated by a +\n";
    print MF "#each line corresponds to a machine\n";
    print MF "#the first column indicates the command to obtain the load on a remote machine\n";
    print MF "#the second column is the command prefix to lauch a job on that remote machine\n";
    print MF "#note that the command must cd into the same directory on the remote machine\n";
    print MF "#as on the local machine. The 'node' command does that automatically.\n";
    print MF "#Type 'node' on the command line for more info.\n";
    print MF "# \n";
    print MF "#the first line sets the threshold load for not starting a job (here 0.5)\n";
    print MF "#do not remove the 'none' keyword\n";
    print MF "echo 0.5 + none\n";
    print MF "#list the machines here\n";
    print MF "#example on a local network (e.g. beowolf) with shared disk\n";
    print MF "rsh machinename uptime | getvalue average + node machinename\n";
    print MF "#secure version of the above\n";
    print MF "ssh user\@machinename uptime | getvalue average + node -s user\@machinename\n";
    print MF "#if the machines do not share the same disk\n";
    print MF "ssh user\@machinename uptime | getvalue average + node -r -s user\@machinename\n";
    print MF "#example for queueing system\n";
    print MF "llq -u $USER | wc -l | awk '{print ($1-4)/2}' + qit \n";
    close (MF) ;
    exit ;
  }
}

open(MF,"$machinefile") ;
  while(<MF>)
  {
    if ( (!(/^ *$/)) && (!(/^ *\#/)) && (!(/^set/)) )
    {
      # command lines return the load level " + " the ``node'' command to run remotely ...
      @cmdline = split /\+/, $_ ;
      $load = `@cmdline[0]` ;
      chop $load ;
      print $load, " + ", @cmdline[1] ;
    }
  }
close(MF) ;