#!/usr/bin/env ruby
pod=<<-POD

=head1 NAME
passenger_memory_stats - Munin plugin to monitor the memory usage of passenger application servers.
Monitors the memory consumed by passenger instances.

=head1 APPLICABLE SYSTEMS
All systems that have passenger installed.

=head1 CONFIGURATION
The plugin needs to execute passenger-memory-stats.
This configuration section shows the defaults of the plugin:

  [passenger_*]
  user root
  command /usr/local/bin/ruby %c
  
Options
  env.passenger_memory_stats '/path/to/passenger-memory-stats'  # Path to passenger memory status.
  env.graph_category 'App'                                      # Graph Category. Defaults to Passenger.

ln -s /usr/share/munin/plugins/passenger_memory_stats /etc/munin/plugins/passenger_memory_stats

=head1 INTERPRETATION
The plugin shows the memory consumed by passenger instances.

=head1 MAGIC MARKERS
  #%# family=auto
  #%# capabilities=autoconf

=head1 VERSION
1.5

=head1 BUGS
None known

=head1 AUTHOR
Ilya Lityuga
Bart ten Brinke - railsdoctors.com

=head1 LICENSE
MIT

POD

# Globals
GRAPH_CATEGORY          = ENV['graph_category'] || 'Passenger'
PASSENGER_MEMORY_STATS  = ENV['passenger_memory_stats'] || '/usr/local/bin/passenger-memory-stats'

# Check if this plugin can run
def autoconf
  begin
    require 'rubygems'
    gem "passenger", ">=2.0"
  rescue Exception => e
    puts "no (Gem not found: #{e})"
    exit 1
  end
  
  status = `#{PASSENGER_MEMORY_STATS}`
  unless $?.success?
    puts "no (error when executing #{PASSENGER_MEMORY_STATS})"
    exit 1
  end
  
  puts "yes"
  exit 0
end

# Describe the graph config
def config
  status = `#{PASSENGER_MEMORY_STATS}`
  memory_info = open('/proc/meminfo', 'r') do |lines|
    lines.inject({}) do |h, line|
      matched = line.match(/^([\w_\(\)]+):\s+(\d+)/)
      h[matched[1].to_sym] = matched[2].to_i * 1024
      h
    end
  end
  upper_limit = memory_info[:MemTotal]
  puts <<-CONFIG
graph_category #{GRAPH_CATEGORY}
graph_title Passenger memory stats
graph_vlabel Bytes
graph_args --base 1000 -l 0 --upper-limit #{upper_limit}
graph_info The memory used by passenger instances on this application server
 
memory.label memory
CONFIG
  exit 0
end
 

# Collect the data
# <tt>debug</tt> Show debug information
def run(debug = false)
  stats = `#{PASSENGER_MEMORY_STATS}`
  
  unless $?.success?
    $stderr.puts "failed executing passenger-memory-stats"
    exit 1
  end

  puts stats if debug

  #### Total private dirty RSS: 81.81 MB
  stats =~ /RSS:\s*([\d\.]+)\s*MB\Z/m
  memory = ($1.to_f * 1024 * 1024).to_i
  puts "memory.value #{memory}"
end
 

# Main
if ARGV[0] == "config"
  config
elsif ARGV[0] == "autoconf"
  autoconf
elsif ARGV[0] == "debug"
  run(true)
else
  run
end