Problem this snippet solves:

This is a script will generate an iRule that will display a maintenance page to users when attached to a virtual server. If the iRule already exists, it can be updated from the script. If a virtual server is specified, the iRule will be applied to it. As a result, the virtual will immediately be shunted to the maintenance page.

How to use this snippet:

Requirements

1. Ruby
2. Ruby Gems
3. F5 iControl for Ruby library
4. other dependencies will be installed with the iControl gem

Installation Steps

1. Install Ruby, Ruby's OpenSSL library, Ruby Gems, and the Ruby iControl libraries
2. Copy this code to /usr/local/bin and chmod +x to make the script executable

3. Run it!

   create-maintenace-page-irule.rb -b 192.168.1.245 -u admin -p admin -f www.mysite.com-maintenance.html -v mymaintenancevirtual

Code :

#!/usr/bin/ruby

require "rubygems"
require "f5-icontrol"
require "getoptlong"

options = GetoptLong.new(
  [ "--bigip-address",  "-b", GetoptLong::REQUIRED_ARGUMENT ],
  [ "--bigip-user",     "-u", GetoptLong::REQUIRED_ARGUMENT ],
  [ "--bigip-pass",     "-p", GetoptLong::REQUIRED_ARGUMENT ],
  [ "--html-file",      "-f", GetoptLong::REQUIRED_ARGUMENT ],
  [ "--maintenance-vs", "-v", GetoptLong::OPTIONAL_ARGUMENT ],
  [ "--irule-name",     "-n", GetoptLong::OPTIONAL_ARGUMENT ],
  [ "--help",           "-h", GetoptLong::NO_ARGUMENT ]
)

def usage
  puts $0 + " -b  -u  -f "
  puts "  -b (--bigip-address)    BIG-IP management-accessible address)"
  puts "  -u (--bigip-user)       BIG-IP username"
  puts "  -p (--bigip-pass)       BIG-IP password (will prompt if left blank"
  puts "  -f (--html-file)        source HTML file for maintenance page"
  puts "  -v (--maintenance-vs)   virtual server to apply maintenance page (will immediiately put virtual server in maintenance mode)"
  puts "  -n (--irule-name)       name of maintenance iRule (defaults to maintenance_page_)"
  puts "  -h (--help)             shows this help/usage dialog"

  exit
end

# initial parameter values

bigip_address = ''
bigip_user = ''
bigip_pass = ''
maintenance_html_file = ''
maintenance_vs = ''
maintenance_irule_name = ''

options.each do |option, arg|
  case option
    when "--bigip-address"
      bigip_address = arg
    when "--bigip-user"
      bigip_user = arg
    when "--bigip-pass"
      bigip_pass = arg
    when "--html-file"
      maintenance_html_file = arg
    when "--maintenance-vs"
      maintenance_vs = arg
    when "--irule-name"
      maintenance_irule_name = arg
    when "--help"
      usage
  end
end

# at the very least, the user should provide be BIG-IP address and username

usage if bigip_address.empty? or bigip_user.empty? or maintenance_html_file.empty?

# make sure that the maintenance page source HTML file exists, if not display error and exit

unless File.exists? maintenance_html_file
  puts "Error: #{maintenance_html_file} could not be located. Check the path and try again."
  exit 1
end

# if no iRule name is specified, built the default

if maintenance_irule_name.empty?
  maintenance_irule_name = "maintenance_page_#{File.basename(maintenance_html_file).gsub('.', '_')}"
end

# if no BIG-IP password is provided, prompt for it

if bigip_pass.empty?
  puts "Please enter the BIG-IPs password..."
  print "Password: "
  system("stty", "-echo")
  bigip_pass = gets.chomp
  system("stty", "echo")
end

# create iControl interfaces

bigip = F5::IControl.new(bigip_address, bigip_user, bigip_pass, ["LocalLB.VirtualServer", "LocalLB.Rule"]).get_interfaces

puts "Connected to BIG-IP at #{bigip_address} with user '#{bigip_user}'..."
puts

# ensure that that virtual server exists before proceeding

unless maintenance_vs.empty?
  unless bigip["LocalLB.VirtualServer"].get_list.include? maintenance_vs
    puts "Error: virtual server '#{maintenance_vs}' could not be located on BIG-IP"
    exit
  end
end

maintenance_irule = "priority 1\n\nwhen HTTP_REQUEST {\n    HTTP::respond 200 content {#{File.read(maintenance_html_file)}}\n}"

irule_definition = {"rule_name" => maintenance_irule_name, "rule_definition" => maintenance_irule}

if bigip["LocalLB.Rule"].get_list.include? maintenance_irule_name
  puts "An iRule named '#{maintenance_irule_name}' already exists. Would you like to replace it? (yes/no)"
  answer = gets

  if answer == "yes\n"
    puts "Updating '#{maintenance_irule_name}' on BIG-IP..."
    bigip["LocalLB.Rule"].modify_rule([irule_definition])
  else
    puts "Nothing to do. Exiting..."
    exit
  end
else
  puts "Creating iRule '#{maintenance_irule_name}' on BIG-IP..."
  bigip["LocalLB.Rule"].create([irule_definition])
end

# assemble a list of iRules already assigned to virtual server

vs_irules = []
bigip["LocalLB.VirtualServer"].get_rule(maintenance_vs)[0].each { |irule| vs_irules << irule['rule_name'] } unless maintenance_vs.empty?

unless maintenance_vs.empty? or vs_irules.include? maintenance_irule_name
  puts "Are you absolutely sure that you want to enable the maintenance iRule for virtual server '#{maintenance_vs}'? (yes/no)"
  answer = gets

  if answer == "yes\n"
    puts "Applying maintenance page iRule to virtual server '#{maintenance_vs}'..."
    bigip["LocalLB.VirtualServer"].add_rule([maintenance_vs], [[{"rule_name" => maintenance_irule_name, "priority" => 1}]])
  end
end

puts "Done!"