a mon's monitor plugin to monitor msgpack-rpc services

msgpack-rpc.monitor.rb

#!/usr/bin/env ruby

require 'rubygems'
require 'msgpack/rpc'
require 'optparse'
require 'yaml'

PROGRAM_NAME = File.basename($0)
EXIT_SUCCESS = 0
EXIT_FAILURE = 1

options = {
  :port => 9090,
  :message => :ping,
  :arguments => [],
  :expected => 'ok',
}

parser = OptionParser.new { |op|
  op.on('-a ARGUMENT', '--argument ARGUMENT') { |argument|
    options[:arguments].push(YAML.load(argument))
  }

  op.on('-m MESSAGE', '--message MESSAGE') { |message|
    options[:message] = message.to_sym()
  }

  op.on('-p PORT', '--port PORT', Integer) { |port|
    if port < 1 or 65535 <= port
      STDERR.puts("out of port range: #{port}")
      STDERR.puts(op.help())

      exit(EXIT_FAILURE)
    end
    options[:port] = port
  }

  op.on('-e EXPECTED', '--expected EXPECTED') { |expected|
    options[:expected] = YAML.load(expected)
  }
}

hosts = parser.parse(ARGV)
results = hosts.map { |host|
  begin
    client = MessagePack::RPC::Client.new(host, options[:port])
    returned = client.call(options[:message], *options[:arguments])
    result = options[:expected] == returned
    unless result
      STDERR.puts("#{host}:#{options[:port]}\##{options[:message]}(#{options[:arguments].join(', ')}): " +
                  "got #{returned}, expected #{options[:expected]}")
    end
    result
  rescue StandardError => error
    STDERR.puts("#{host}:#{options[:port]}\##{options[:message]}(#{options[:arguments].join(', ')}): " +
                "#{error}")
    false
  end
}

exit(results.reduce(true) { |all, result| all && result } ? EXIT_SUCCESS : EXIT_FAILURE)

# vim:set ft=ruby :