Non Blocking CPU Stats (1s) using Mojo::IOLoop:Delay

cpu-stats-nb.pl

#!/usr/bin/env perl
use Mojo::Base -strict;
use Mojo::File 'path';
use Mojo::Collection 'c';
use Mojo::IOLoop;
use Mojo::JSON 'j';

BEGIN {
	#only linux is supported !
	#!linux
	die( sprintf( "OS %s not supported !\n", $^O ) ) if $^O ne 'linux';
}

sub read_cpu {
	my $file = shift;
	my $fh   = path($file)->open('r+');
	while (<$fh>) {
		chomp;
		if (/^cpu\s+/) {
			( my $content ) = /^cpu\s+(.*)/g;
			close($fh) and return c( split( /\s+/, $content ) );
		}
		else { die( sprintf( "Cannot read stats file %s !\n", $file ) ); }
	}
	close $fh;

}

sub get_stats {
	my $file       = q{/proc/stat};
	my $prev_total = 0;
	my $prev_stat  = c();
	my $out        = c();

	my $stats = sub {
		my $collection = c();
		my $total      = 0;
		$collection = read_cpu($file);
		$collection->map( sub { $total += $_ } );
		my $diff_total = $total - $prev_total;
		$collection->each(
			sub {
				my ( $value, $key ) = @_;
				$out->[ int($key) - 1 ] = sprintf( "%.1f%s",
					( 100 * ( $value - ( $prev_stat->[ int($key) - 1 ] // 0 ) ) / $diff_total ), q{%} );
			}
		);
		$prev_stat  = $collection;
		$prev_total = $total;
	};

	my $delay = Mojo::IOLoop::Delay->new;
	$delay->steps(
		sub {
			my $delay = shift;

			my $end = $delay->begin;
			$stats->();
			$end->();
		},
		sub {
			my $delay = shift;

			Mojo::IOLoop->timer( 1 => $delay->begin );
		},
		sub {
			my $delay = shift;

			my $end = $delay->begin;
			$stats->();
			$end->();
		},
		sub {
			my ( $delay, @args ) = @_;
			my $cpu_info->{cpu_info} = {};
			my $out_c = c(qw(huser nice sys idle iowait irq softirq steal guest guest_nice));
			$out_c->each(
				sub {
					my ( $value, $key ) = @_;
					$cpu_info->{cpu_info}->{$value} = $out->[ $key - 1 ];

				}
			);
			printf( "%s", j($cpu_info) );
		}
	)->wait;
}

get_stats;

1;