#!/usr/bin/perl
use warnings;
use strict;
use autodie;
use POSIX;
use Time::HiRes qw(time sleep);

my $DEBUG = $ENV{DEBUG} || 0;
my $INFLUX = $ENV{INFLUX} || 'http://10.80.3.89:8086/write?consistency=any&db=gnt';
my $INTERVAL = $ENV{INTERVAL} || 1;
my $DC = $ENV{DC};
my $RACK = $ENV{RACK};

my $node = `hostname -s`;
chomp $node;

my $location = '';
$location .= qq{,dc=$DC} if $DC;
$location .= qq{,rack=$RACK} if $RACK;

warn $0 = "gnt-monitor\@$node$location $INFLUX $INTERVAL $DEBUG";

use Data::Dump;
sub XXX { $DEBUG ? warn "XXX ",Data::Dump::dump( @_ ) : {} };

my $stat;
my $last;

while(1) {

my $skip;

my $begin_t = time();
my $t = int( time() * 1000_000_000 );

foreach my $instance ( glob '/var/run/ganeti/kvm-hypervisor/pid/*' ) {

	open(my $fh, '<', $instance);
	my $pid = <$fh>; chomp $pid;

	$instance =~ s{^.*/}{};

	if ( ! -d "/proc/$pid" ) {
		$skip->{$instance}++;
		XXX $skip;
		next;
	}

	my $vcpu = $last->{$instance}->{vcpu};

	if ( ! $vcpu ) {
		foreach my $fd ( glob "/proc/$pid/fd/*" ) {
			$vcpu++ if -l $fd && readlink($fd) =~ m/kvm-vcpu/;
		}

		$last->{$instance}->{vcpu} = $vcpu;
	}

	# https://www.kernel.org/doc/Documentation/filesystems/proc.txt
	open($fh, '<', "/proc/$pid/stat");
	my $line = <$fh>; chomp $line;
	my $gtime = (split(/\s+/,$line))[42]; # guest time of the task in jiffies

	if ( my $last_gtime = $last->{$instance}->{gtime} ) {
		my $clock_ticks = POSIX::sysconf( &POSIX::_SC_CLK_TCK ); # clock ticks per second

		my $cpu = ( ( $gtime - $last_gtime ) * 100 ) / ( $clock_ticks * $vcpu ) / $INTERVAL;
		$stat->{$instance}->{cpu} = $cpu;
		$stat->{$instance}->{ticks} = ($gtime - $last_gtime) / $INTERVAL;
	}

	$last->{$instance}->{gtime} = $gtime;
}
		

foreach my $glob ( glob '/var/run/ganeti/instance-disks/*' ) {
	my ( $instance, $disk ) = split(/:/,$glob,2);
	$instance =~ s{^.*/}{};

	next unless exists $stat->{$instance};

	my $dev = readlink $glob;
	$dev =~ s{^.*dev/}{};

	if ( ! -e "/sys/class/block/$dev" ) {
		$skip->{$instance}++;
		XXX $skip;
		next;
	}

	open( my $fh, '<', "/sys/class/block/$dev/stat" );
	my $v = <$fh>; chomp $v; $v =~ s/^\s+//;
	my @s = split(/\s+/, $v );
	# https://www.kernel.org/doc/Documentation/block/stat.txt
	my $d = {
		read_io => $s[0] / $INTERVAL,
		read_bytes => $s[2] * 512 / $INTERVAL,
		read_wait => $s[3] / $INTERVAL,
		write_io => $s[4] / $INTERVAL,
		write_bytes => $s[6] * 512 / $INTERVAL,
		write_wait => $s[7] / $INTERVAL,
	};
	if ( my $l = $last->{$instance}->{disk}->[$disk] ) {
		my $delta;
		$delta->{$_} = $d->{$_} - $l->{$_} foreach keys %$d;
		$stat->{$instance}->{disk}->[$disk] = $delta;
		$stat->{$instance}->{disk}->[$disk]->{dev} = $dev;
		$stat->{$instance}->{disk}->[$disk]->{disk} = $disk;
	}
	$last->{$instance}->{disk}->[$disk] = $d;

}

foreach my $full_instance ( glob '/var/run/ganeti/kvm-hypervisor/nic/*' ) {
	my $instance = $full_instance;
	$instance =~ s{^.*/}{};
	next unless exists $stat->{$instance};

	foreach my $nic ( glob "$full_instance/*" ) {
		open(my $fh, '<', $nic);
		my $dev = <$fh>;

		next unless -e "/sys/class/net/$dev";

		$nic =~ s{^.*/}{};

		my $d;

		foreach my $f (qw( rx_bytes tx_bytes rx_packets tx_packets )) {
			open( my $fh, '<', "/sys/class/net/$dev/statistics/$f" );
			my $v = <$fh>; chomp $v;
			$d->{$f} = $v / $INTERVAL;
		}
		if ( my $l = $last->{$instance}->{nic}->[$nic] ) {
			$stat->{$instance}->{nic}->[$nic]->{$_} = $d->{$_} - $l->{$_} foreach keys %$d;
			$stat->{$instance}->{nic}->[$nic]->{dev} = $dev;
			if ( -e "/sys/class/net/$dev/master" ) {
				my $vlan = readlink "/sys/class/net/$dev/master";
				$vlan =~ s/^.*br//;
				$stat->{$instance}->{nic}->[$nic]->{vlan} = $vlan;
			}
		}
		$last->{$instance}->{nic}->[$nic] = $d;

	}
}

#XXX $stat;
#XXX $last;

sub dump4influx {
	my $hash = shift;
	my @v;
	foreach my $k ( keys %$hash ) {
		my $v = $hash->{$k};
		my ( $d, $s ) = $v =~ m/^\d+(\.\d+)?$/i ? ( '',  ''  ) : # float
                                                     ( '"' ,''  ) ; # string

		push @v, "$k=$d$v$d$s";
	}
	my $i = join(',', @v);
	return $i;
}

open(my $fh, '>', '/dev/shm/gnt-monitor.influx');

foreach my $instance ( keys %$stat ) {

	next if $skip->{$instance};

	print $fh qq{ganeti_cpu,node=$node,instance=$instance$location cpu=$stat->{$instance}->{cpu},ticks=$stat->{$instance}->{ticks} $t\n};

	foreach my $disk ( @{ $stat->{$instance}->{disk} } ) {
		print $fh qq{ganeti_disk,node=$node,instance=$instance$location },dump4influx( $disk ), " $t\n";
	}

	foreach my $nic ( @{ $stat->{$instance}->{nic} } ) {
		my $vlan = delete $nic->{vlan};
		$vlan = 0 unless defined $vlan;
		print $fh qq{ganeti_nic,node=$node,instance=$instance,vlan=${vlan}$location },dump4influx( $nic ), " $t\n";
	}

}

close($fh);

if ( system( 'curl', '-s', '-XPOST', $INFLUX, '--data-binary', '@/dev/shm/gnt-monitor.influx' ) == 0 ) {
} else {
	rename '/dev/shm/gnt-monitor.influx', '/dev/shm/gnt-monitor.influx.bug.' . scalar glob '/dev/shm/gnt-monitor.influx.bug.*';
	warn "curl failed: $? $!";
}

my $dt = time() - $begin_t;
sleep $INTERVAL - $dt if $dt > 0 && $dt < $INTERVAL;
} #/while