root/linen/trunk/examples/host.rb

#!/usr/bin/env ruby
#
# Demonstrates more complex arguments and commands than
# math.rb, including a two-phase command (edit).
#
# == Authors
#
# * Ben Bleything <bbleything@laika.com>
#
# == Copyright
#
# Copyright (c) 2008 LAIKA, Inc.
#
# This code released under the terms of the BSD license.
#
# == Version
#
#  $Id$
#

require 'rubygems'
require 'linen'
require 'ostruct'
require 'ping'
require 'socket'

class HostPlugin < Linen::Plugin
    description "Inspect and check machines on your network."

    argument :ip,
             :prompt  => 'Please enter the IP address: ',
             :regex   => /^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/,
             :process => lambda { |ip|
                ip.split('.').each do |octet|
                    octet = octet.to_f

                    fail "#{ip} is not valid: #{octet.to_i} must be between 0 and 255." if octet < 0 or octet > 255
                end

                return ip
             }
            
    argument :hostname,
             :prompt => 'Please enter the hostname: ',
             :regex  => /^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,6}$/
             # pattern yoinked from http://regexlib.com/REDetails.aspx?regexp_id=391
    
    argument :mac,
             :prompt => 'Please enter the MAC address: ',
             :process => proc {|mac|
                stripped_mac = mac.gsub( /:/, '' )
                fail "MAC Address is too short." unless stripped_mac.length == 12
                fail "MAC Address contains invalid characters." unless stripped_mac =~ /^[0-9a-f]*/i

                return stripped_mac.scan( /../ ).join( ':' )
            }

    command :lookup do
        help_message "Attempts to do a DNS lookup on the IP or hostname provided."

        one_of :ip, :hostname

        action do
            ip_addr_info = Socket.getaddrinfo( ip, nil ) rescue nil
            hn_addr_info = Socket.getaddrinfo( hostname, nil ) rescue nil

            if ip_addr_info
                say "IP address #{ip} has hostname #{ip_addr_info[0][2]}."
            elsif hn_addr_info
                say "Hostname '#{hostname}' has IP address #{hn_addr_info[0][3]}."
            else
                say "You said something I do not understand.  I am sorry."
            end
        end
    end

    command :check do
        help_message "Attempts to ping the IP or hostname provided."

        one_of :ip, :hostname

        require_confirmation

        action do
            to_check = ip || hostname

            if Ping.pingecho( to_check, 5 )
                say "Host #{to_check} is alive!"
            else
                say "Host #{to_check} appears to be dead :("
            end
        end
    end
    
    command :edit, :lookup_first => true do
        help_message "Lets you pretend to change the host's IP and MAC addresses.  Lookup by hostname."

        lookup_by :hostname do |hostname|
            out          = OpenStruct.new
            out.hostname = hostname
            out.ip       = Socket.getaddrinfo( hostname, nil )[0][3]
            
            # yoinked this from a thread on ruby-talk about UUID generation
            # http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/242664
            out.mac = ("%012x" % rand(1 << 12*4)).scan( /../ ).join( ':')
            
            # return
            out
        end
        
        inspect do
            say "Hostname:    #{hostname.hostname}"
            say "IP Address:  #{hostname.ip}"
            say "MAC Address: #{hostname.mac}"
        end
        
        editable_attributes :ip, :mac
        
        action do
            say "If this was real, you would have just changed #{hostname.hostname}'s IP address to " +
                "#{ip.empty? ? 'nothing' : ip} and its MAC address to #{mac.empty? ? 'nothing' : mac}.  " +
                "It's not real, though, so rest easy."
        end
    end
end

Linen::CLI.prompt = "host > "
Linen.start