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#! /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";
}

sub loadVirtDB {
   return if $virtDB;
   $virtDB = &readDB( $domainDBName );
}

sub domain {
   my $action = lc shift;
   my $return = '';
   &loadVirtDB();
   &loadNodePopulations();
   @_ = keys( %$virtDB ) if ( $_[0] && $_[0] eq 'ALL' );
   if ( $_[0] && $_[0] eq 'RUNNING' ) {
      my @running;
      foreach my $node ( keys %$nodePopulations ) {
         push @running, keys %{ $nodePopulations->{$node}->{'running'} };
      }
      @_ = @running;
   }
   if ( $action eq 'update' ) { # download xml to var and update database
      while ( my $virt = shift ) {
         &parseDomain( $virt );
      } # while
      &writeDB( $domainDBName, $virtDB );
   } elsif ( $action eq 'list' ) { # dump domain as a tab separated data file
      my @return;
      foreach my $node ( keys %$nodePopulations ) {
         foreach my $virt (keys %{$nodePopulations->{$node}->{'running'}} ) {
            push @return, &listDomain( $virt, $node );
         }
      }
      $return = join( "\n", sort @return ) . "\n";;
   }
   return $return;;
} # sub domain

sub listDomain {
   my ($virt,$node) = @_;
   my @return;
   push @return, $virt;
   push @return, $node;
   foreach my $column ( sort keys %{ $virtDB->{$virt} } ) {
      push @return, $virtDB->{$virt}->{$column};
   }
   return join( "\t", @return);
}
   


# get the XML definition file of a running domain off of whatever
# node it is running on, and save it to disk
sub getVirtConfig {
   my ($virt,$filename) = @_;
   my $return;
   print "In getVirtConfig looking for $virt with file $filename\n" if $DEBUG;
   if ( -f $filename ) {
      open XML, "<$filename" or die "Could not read from $filename: $!\n";
      $return = join( '', <XML> );
      close XML;
   } else {
      &loadNodePopulations();
      #die Dumper( $nodePopulations );
      foreach my $node ( keys %$nodePopulations ) {
         print "getVirtConfig Looking on $node for $virt\n";
         if ( exists( $nodePopulations->{$node}->{'running'}->{$virt} ) ) { # we found it
            print "Found $virt on node $node\n";
            $return = `ssh $node 'virsh dumpxml $virt'`;
            open XML,">$filename" or die "Could not write to $filename: $!\n";
            print XML $return;
            close XML;
         } # if
      } # foreach
   } # if..else
   return $return;
} # sub getVirtConfig

sub getXMLValue {
   my ( $key, $string ) = @_;
   my $start = "<$key";
   my $end = "</$key>";
   $string =~ m/$start([^>]*)>([^<]+)$end/;
   return ($1,$2);
}

sub parseDomain {
   my ($virt, $nodePopulations ) = @_;
   
   my @keysToSave = ( 'uuid', 'memory', 'vcpu' );
   my $filename = "$confDir/$virt.xml";
   my $xml = &getVirtConfig( $virt, $filename );
   my ($param,$value) = &getXMLValue( 'uuid', $xml );
   $virtDB->{$virt}->{'uuid'} = $value;
   ($param,$value) = &getXMLValue( 'memory', $xml );
   $virtDB->{$virt}->{'memory'} = $value;
   ($param,$value) = &getXMLValue( 'vcpu', $xml );
   $virtDB->{$virt}->{'vcpu'} = $value;

   $xml =~ m/type='vnc' port='(\d+)'/;
   $virtDB->{$virt}->{'vnc'} = $1;
}

sub cluster {
   my $action = lc shift;
   my $return = '';
   if ( $action eq 'status' ) {
      &loadVirtDB();
      &loadNodePopulations();
      &loadNodeDB();
      print "Node\tThreads\tMemory\tDomains\tvcpu\tmem_used\n";
      my $usedmem = 0;
      my $usedcpu = 0;
      my $availmem = 0;
      my $availcpu = 0;
      my $totalDomains = 0;
      foreach my $node (sort keys %$nodeDB ) {
         my $memory = 0;
         my $vcpus = 0;
         my $count = 0;
         foreach my $domain ( keys %{ $nodePopulations->{$node}->{'running'} } ) {
            $memory += $virtDB->{$domain}->{'memory'};
            $vcpus += $virtDB->{$domain}->{'vcpu'};
            $count++;
         }
         $return .= "$node\t$nodeDB->{$node}->{cpu_count}\t$nodeDB->{$node}->{memory}\t$count\t$vcpus\t$memory\n";
         $usedmem += $memory;
         $usedcpu += $vcpus;
         $totalDomains += $count;
         $availmem += $nodeDB->{$node}->{memory};
         $availcpu += $nodeDB->{$node}->{cpu_count};
      } # outer for
      $return .= "Total\t$availcpu\t$availmem\t$totalDomains\t$usedcpu\t$usedmem\n";
   }
   return $return;
}


# 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 . '::' . $action;
# load the module, die if it doesn't exist. Might make this an eval later
require "$command.pm";
Module->import( $command ); # for require, you must manually import

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";
} 


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