lxc-top -- Crappy ruby code to show top lxc containers eating cpu

lxc-top

#!/usr/bin/env ruby
require 'yaml'
require 'curses'
include Curses

class Container
  attr_accessor  :name, :secs, :elapsed, :pct, :last_check, :mem
  def initialize(name, secs)
    @name = name
    @secs = secs
    @elapsed = 0
    @pct = 0.0
    @last_check = nil
    @mem = ""
  end
end




def show_top(top)
    clear
    attrset(A_REVERSE)
    setpos(0,0)
    addstr(" "*80)
    setpos(0,0)
    addstr("CONTAINER")
    setpos(0,48)
    addstr("CPU %")
    setpos(0, 58)
    addstr("MEM")
    attrset(A_NORMAL)
    top.each_with_index  do |c, i|
		setpos(i+1, 0)
		addstr(c.name)
		setpos(i+1, 48)
		addstr("#{c.pct}")
		setpos(i+1, 58)
		addstr(c.mem)
    end
    refresh
end

def run
    container_map = {}
    top_items = 0
    first = true
    if  `lxc-ls` == ""
        puts "No containers found or you are not root."
        exit 3
    end
	init_screen
    Curses.timeout=0
	curs_set(0)
    setpos(0,0)
    addstr("lxc-top initializing...")
    refresh
    begin
        crmode
        loop do
            top_items = lines - 4
            containers = `lxc-ls`
            containers.split(' ').each do |container|
                return if Curses.getch == 'q'
                info = `lxc-info -n #{container}`
                m = /CPU use: +([\d.]+)/.match(info)
                check_time = Time.now
                if m != nil
                    c = Container.new(container, m[1].to_f)
                    last = container_map[container]
                    if last != nil
                        dur = (check_time - last.last_check).to_f
                        c.elapsed = c.secs - last.secs
                        c.pct = (c.elapsed/dur * 100).to_i
                    end
                    m = /Memory use: +(.*)/.match(info)
                    if m != nil
                        c.mem = m[1]
                    end
                    c.last_check = check_time
                    container_map[container] = c
                end
            end
            # Sort by elapsed time
            top = container_map.values.sort(){|l, r| r.elapsed <=> l.elapsed}[0..top_items]
            unless first
                show_top(top)
            end
            first = false
            sleep 1
        end
    rescue Interrupt
    	return
    ensure
        close_screen
    end
end

run

We show what I think is the right way to calculate cpu pct, but that could be wrong. Should still give you a basic idea of the magnitude of impact on the system of a given container