munin plugin to check process existence for NetBSD, implemented with Ruby

healthcheck_process

#!/usr/local/bin/ruby

PS = "/bin/ps"

keys = ENV.keys.grep(/^process_\d+$/).sort_by{|e| e.split(/_/, 2).last.to_i}

arg = ARGV.shift

if arg == "autoconf"
  if keys.empty?
    puts "no"
    exit 1
  else
    puts "yes"
    exit 0
  end
end

if arg == "config"
  puts <<-EOC
graph_title Process memory usage
graph_args --base 1000 -l 0 --vertical-label MB
graph_scale no
graph_vlabel process memory (MB)
graph_category healthcheck
  EOC

  keys.each do |key|
    puts <<-EOC
#{key}.label #{ENV[key]}
#{key}.draw LINE2
#{key}.min -10
#{key}.critical 0:
    EOC
  end

  exit 0
end

# run
def process_name(cmd)
  args = cmd.split(/\s+/)
  if /^\w+:$/ =~ args[0]
    args[0, 2].join(' ')
  elsif /^\(([^\)]+)\)$/ =~ args[0]
    $1
  else
    args[0]
  end
end

ps = `#{PS} awwx -o user,vsz,command`.lines.to_a[1..-1].map{|line| user, sz, cmd = line.strip.split(/ +/, 3); [sz.to_i, user, process_name(cmd)]}
keys.each do |key|
  by_user = ENV[key + "_by"] == "user"
  data = ps.select{|sz, user, cmd| by_user ? user == ENV[key] : Regexp.compile("\\b#{Regexp.quote(ENV[key])}\\b") =~ cmd}.map(&:first)
  if data.empty?
    puts "#{key}.value -10"
    puts "#{key}.extinfo the process is down"
  else
    puts "#{key}.value #{'%.2f' % [data.inject(0, &:+) / 1024.0]}"
  end
end

Settings example:

[healthcheck_process]
env.process_1 postfix
env.process_1_by user
env.process_2 postgrey
env.process_3 amavisd
env.process_4 clamd
env.process_5 named
env.process_6 httpd
env.process_7 squid

This is a clone of "healthcheck_process" at http://d.hatena.ne.jp/rti7743/20110604/1307219520 .
The original was written for bash and GNU ps, therefore I've re-implemented with Ruby and NetBSD ps.