Push: A Perl script to distribute a file to several servers.

[bpoag]

Here's a handy tool I built, that uses rsh/rcp to distribute a given file to several hosts. See comments for explanation of voodoo magic.

#!/usr/bin/perl
##
## Push v0.1 written 030105:1209 by Bowie J. Poag
##
## This script pushes a given filename to all servers..if possible. :)
##
## Usage:  push <filename> [destination_dir]
##
## This script requires certain conditions to be present in order to
## work correctly.
##
## First, all the hosts listed in the @hosts array must have their
## /.rhosts file configured to allow the host named in $distributorBox
## to perform rsh and rcp commands.
##
## Pick any box on you have access to. This box will act as your
## distributor box. 
##
## The $distributorBox is the host responsible for passing out copies
## to the others. In this case, our distributorBox is named 'devo'.
##
## When this script is called, it first checks to see what host it's
## on. If it's being run from the distributor box, it will go ahead
## and pass out the file to the others. If the script sees that it's
## NOT on the distributor box, it will send a copy to the distributor,
## and then tell the distributor to pass it out. Kinda neat. :)
##
## This script should be kept in /usr/local/bin.
##
## To install this script network wide, simply push a copy of 'push':
##
## # /usr/local/bin/push /usr/local/bin/push /usr/local/bin
##
## :)


$distributorBox="devo";   # Set this to the box/IP address of your cho
+ice.


startupRoutine();
sanityCheck();
figureOutWhatToDoFirst();
spinDownRoutine();


sub startupRoutine()
{
   $user=`whoami`;
   $whereAmI=`hostname`; # $ENV{'HOSTNAME'} is non-ubiquitous in *nix.
   chomp($user);
   chomp($whereAmI);

   @hosts=(
      "moe",
      "larry",
      "shemp.nowhere.com",
      "curly.norad.gov",
      "shemp.org",
      "joe",
      "harpo.ee.ucsd.edu",
      "zeppo",
      "chico.net",
      "gummo",
      "groucho",
      "karl", # Not a Marx brother, but still hilarious.
      );

  print "Push (on $whereAmI): Starting up..\n";
}


sub sanityCheck()
{
   if ($#ARGV < 0 || $#ARGV > 1 || $user ne "root") 
   {
      die("  Usage:  $0 <filename> [location on remote host]\n\n  Note
+: You must be root to use this command.  If no target directory is gi
+ven, the name of the current directory is used. \n\
n");
   }

   $fileName=$ARGV[0];
   chomp($targetPath=$ARGV[1] || `pwd`); 
   if(!$ARGV[1]) { print "Push (on $whereAmI): Warning -- Target path 
+not specified. Assuming current directory..\n";  }
   (-e $fileName) or die("Push (on $whereAmI): Eh? That file doesn't e
+xist here on $whereAmI.. Try again.\n\n");
   $targetPath=~s'\/$''g;     # Strip the trailing whack..
}

sub figureOutWhatToDoFirst()
{
   if ($whereAmI eq $distributorBox)
   {
      pushRoutine();
   }

   else
   {
      $src="$fileName";
      $trg="$distributorBox:$targetPath";
      print "Push (on $whereAmI): Sending $fileName to $distributorBox
+ for distribution..\n";
      system("rcp $src $trg");
      system("rsh $distributorBox /usr/local/bin/push $fileName $targe
+tPath");
   }
}


sub pushRoutine()
{
   if ($whereAmI eq $distributorBox)
   {

      foreach $box (@hosts)
      {
         $src="$fileName";
         $trg="$box:$targetPath";
         print "Push (on $whereAmI): Sending $src from $whereAmI to $t
+rg..\n";
         system("rcp $src $trg");
      }
   }
}


sub spinDownRoutine()
{
   print "Push (on $whereAmI): Spinning down..\n";
   exit; # bonk
}

[cazz]

Been there done that, didn't buy the t-shirt, it wsa too expensive.

Toss in some Parallel::ForkManager in there and do the push in parallel.

Replace rsh with ssh, add some pub/priv keys, and then you can do that with security!

[bpoag]

Hi cazz,

Yeah -- Thought about both of those ideas, actually. I try to stick with tools that are ubiquitous across several platforms, which ruled out ssh. Forking the rsh/rcp stuff would have added alot of extra overhead, not to mention the need to install Parallel::ForkManager across the board. Between different Unicies and different versions of Perl, that can be a super pain.

This script was also developed in-house, where all the machines are peered on a private subnet without a need for added security. :) Provided you dont have like 500 different hosts listed in the array, it's fine to do them sequentially, I figure. :)

Cheers, Bowie

[cazz]

Parallel::ForkManager is pure perl. No need to install it, just cut & paste into your script.