Subversion Repositories havirt

#! /usr/bin/env perl

use strict;

use warnings;

# havirt

# Basically an extension of virsh which will perform actions on virtuals 

# running on multiple, connected hypervisors (virsh calls them nodes)

# existing as a cluster of hypervisors where virtuals can be shut down,

# started and migrated at need.

#

# Progam consists of one executable (havirt) and multiple Perl Modules

# (*.pm), each of which encompasses a function. However, this is NOT

# written as an Object Oriented system.

#

# havirt --help gives a brief help screen.

# Copyright 2024 Daily Data, Inc.

# 

# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following 

# conditions are met:

#

#   Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

#   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer 

#   in the documentation and/or other materials provided with the distribution.

#   Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived

#   from this software without specific prior written permission.

# 

# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT

# NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL

# THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE

# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#use experimental "switch";

# requires File::Slurp. 

# In Debian derivatives

# apt install libfile-slurp-perl

# apt install libxml-libxml-perl libyaml-tiny-perl

BEGIN {

   use FindBin;

   use File::Spec;

   # use libraries from the directory this script is in

   use Cwd 'abs_path';

   use File::Basename;

   use lib dirname( abs_path( __FILE__ ) );

}

use havirt; # Load all our shared stuff

use Data::Dumper;

use YAML::Tiny;

# define the version number

# see https://metacpan.org/pod/release/JPEACOCK/version-0.97/lib/version.pod

use version;

our $VERSION = version->declare("0.0.1");

# see https://perldoc.perl.org/Getopt/Long.html

use Getopt::Long;

# allow -vvn (ie, --verbose --verbose --dryrun)

Getopt::Long::Configure ("bundling");

# global variables

my $scriptDir = $FindBin::RealBin;

my $scriptName = $FindBin::Script;

my $dbDir = "$scriptDir/var";

our $confDir = "$scriptDir/conf";

our $nodeDBName = "$dbDir/node.yaml";

our $domainDBName = "$dbDir/domains.yaml";

our $nodePopulationDBName = "$dbDir/node_population.yaml";

# these contain the values from the databases

# loaded on demand

our $nodeDB;

our $virtDB;

our $nodePopulations;

# options variables

our $reportFormat = 'screen';

our $targetNode = '';

our $dryRun = 1;

our $DEBUG = 0;

my $help = 0;

my $version = 0;

sub help {

   print "$0 command [argument]\n";

   print "where command is one of\n";

   print "\tnode update|list|scan # work with a node\n";

   print "\tdomain update|list # work with individual domains\n";

   print "\tcluster status # report of memory and vcpu status on all nodes\n";

   print "For additional help, run command help\n";

   print "\tnode help # or domain, or cluster\n";

   print "Some flags can be used where appropriate\n";

   print "\t--help|-h # show this screen\n";

   print "\t--version|-v # show version of program\n";

   print "\t--format|-f screen|tsv # output of list commands is either padded for screen or Tab Delim\n";

   print "\t--target|-t NODE # the action use NODE for the target of actions\n";

   print "\t--dryrun|-n # does not perform the actions, simply shows what commands would be executed\n";

   print "\t--debug|d # increases verbosity, with -ddd, totally outragious\n";

}

# handle any command line parameters that may have been passed in

GetOptions (

   'format|f=s' => \$reportFormat,

   'target|t=s' => \$targetNode,

   'dryrun|n!' => \$dryRun,

   'debug|d+' => \$DEBUG,

   'help|h' => \$help,

   'version|v' => \$version

) or die "Error parsing command line\n";

my $command = shift; # the first one is the actual subsection

my $action = shift; # second is action to run

if ( $help || ! $command ) { &help() ; exit; }

if ( $version ) { use File::Basename; print basename($0) . " v$VERSION\n"; exit; }

print "Parameters are\nreportFormat\t$reportFormat\ntargetNode\t$targetNode\ndryRun\t$dryRun\nDEBUG\t$DEBUG\n" if $DEBUG;

print "Command = $command\nAction = $action\n" if $DEBUG;

# we allow a three part command for some actions on a domain, ie start, shutdown, migrate and destroy

# for simplicity, if the command is one of the above, allow the user to enter like that, but we will

# restructure the command as if they had used the full, three part (ie, with domain as the command)

# so, the following are equivilent

# havirt domain start nameofdomain

# havirt start nameofdomain

if ( $command eq 'start' || $command eq 'shutdown' || $command eq 'migrate' || $command eq 'destroy' ) { # shortcut for working with domains

   push @ARGV, $action; # this is the domain we are working with

   $action = $command; # this is what we want to do (start, shutdown, etc...)

   $command = 'domain'; # keywork domain, for correct module

}

# ok, this is some serious weirdness. $command is actually the name of a module, and $action is a method

# defined in the module.

# I use 'require' which loads at runtime, not compile time, so it will only load a module if needed.

# then, I check to see if a method named in $action is defined within that module and, if so

# execute it and return the result. If not, gives an error message.

# This means to add functionality, we simply add a method (sub) in a given module, or create a whole

# new module.

# we have to concat here since the double colon causes some interpretation problems

my $execute = $command . '::' . $action;

# load the module, die if it doesn't exist.

if (-f $scriptDir . "/$command.pm" ) {

   require "$command.pm";

   Module->import( $command ); # for require, you must manually import

} else {

   die "Error, I don't know the command [$command]\n";

}

if ( defined &{\&{$execute}} ) { # check if module::sub exists (ie, $command::action)

  print &{\&{$execute}}(@ARGV); # yes, it exists, so call it with any remaining arguments

} else { # method $action does not exist in module $command, so just a brief error message

  die "Error, could not find action [$action] for module [$command]\n";

} 

1;