Given a Cisco switch, enable/disable power on every PoE port that has an IP Phone connected to it.

phonesonoff.rb

#!/usr/bin/env ruby

# - Connects to a Cisco switch
# - Asks CDP which ports have an "IP Phone" connected to them
# - On every such port, turn PoE on or off
#
# -- giuliano@108.bz

require 'greenletters'
require 'trollop'
require 'yaml'
YAML::ENGINE.yamler='syck'

# Captures all output in a buffer, optionally sending it to stdout as well
class StdoutBufferTranscript
    def initialize
        @buffer    = String.new
        @to_stdout = false
    end

    def clear
        @buffer = String.new
    end

    def buffer
        StringIO.new @buffer
    end

    def stdout(onoff); @to_stdout = onoff; end
    def on;            @to_stdout = true;  end
    def off;           @to_stdout = false; end

    def <<(output)
        $stdout << output if @to_stdout
        @buffer << output
        self
    end
end

module CiscoPrompt
    def set_prompt_name(name)
        @cisco_prompt_name = name
    end

    def wait_for_prompt(suffix = '#')
        wait_for :output, /^#{Regexp.escape(@cisco_prompt_name+suffix)}$/
    end
end

opts = Trollop::options do
    opt :ip, "Switch/Router telnet IP address", :type => :string
    opt :pw, "Password", :type => :string
    opt :ena, "Enable password", :type => :string
    opt :doit, "Do stuff, instead of just showing which interfaces would be affected", :default => false
    opt :poe, "Enable disable PoE on the phones ports", :type => :string, :default => 'on'
    opt :file, "YAML file used for dumping/reading the affected ports list", :type => :string
end

[:ip, :pw, :ena].each do |o|
    Trollop::die o, "must be supplied and it cannot be empty" unless !opts[o].nil? && !opts[o].empty?
end
Trollop::die :poe, "can either be `on' or `off'" unless ['on','off'].include? opts[:poe]
if opts[:doit]
    if opts[:poe] == 'off' 
        Trollop::die :file, "must be a valid file name" unless !opts[:file].nil? && !opts[:file].empty?
        Trollop::die :file, "refusing to overwrite existing file" if File.exist? opts[:file]
    else
        Trollop::die :file, "must be the name of an existing file" unless File.exist? opts[:file]
    end
end

out = StdoutBufferTranscript.new
t   = Greenletters::Process.new "telnet #{opts[:ip]}",
                                :timeout => 10,
                                :transcript => out

t.extend(CiscoPrompt)
t.start!

t.wait_for :output, /^Password:/
out.clear
t << opts[:pw] << "\n"

t.wait_for :output, />$/
name = out.buffer.readlines[-1].sub(/>$/,'') 
puts "Device name is #{name}"
t.set_prompt_name name

t << "enable\n"
t.wait_for :output, /^Password:/
t << opts[:ena] << "\n"
t.wait_for_prompt
out.clear
out.on
if opts[:poe] == 'off'
    t << "show cdp neighbors\n"
    t.wait_for_prompt
    phones = out.buffer.select {|l| l.match ' IP Phone '}.map {|l| f = l.split(/ +/); {:id => f[0], :ifc => f[1]+f[2]} }
else
    if opts[:file] && File.exist?(opts[:file])
        phones = YAML.load(IO.read(opts[:file]))
    else
        phones = []
    end
end

out.clear

if phones.length == 0
    puts "\n\n\n### No phones found/loaded from file"
    exit
end

if !opts[:doit]
    puts "\n\n\n### Found these phones/interfaces:"
    p phones
    exit
end

if opts[:poe] == 'off'
    File.open(opts[:file], "w") do |f|
        f.write(phones.to_yaml)
    end
end

t << "configure terminal\n"
t.wait_for_prompt '(config)#'

mode = (opts[:poe] == 'on') ? 'auto' : 'never'

phones.each do |p|
    puts "\n! #{p[:id]}\n"
    t << "interface #{p[:ifc]}\n"
    t.wait_for_prompt '(config-if)#'
    t << "power inline #{mode}\n"
    t.wait_for_prompt '(config-if)#'
    t << "exit\n"
    t.wait_for_prompt '(config)#'
    sleep 1
end

t << "exit\n"
puts