example rightscript

gistfile1.txt

#!/bin/env ruby
#
# Copyright (c) 2007-2011 RightScale, Inc, All Rights Reserved Worldwide.
#

# Contacts and configures an HAProxy server for user with a generic apache application
# LB_APPLISTENER_NAME -- specifies which HAProxy server pool to use
# LB_BACKEND_NAME -- A unique name for each back end e.g. (AMI_INSTANCE_ID)
# MAX_CONN_PER_SERVER -- Maximum number of connections per server
# HEALTH_CHECK_URI -- 
# APP_PORT -- Port which the LB connect to the app web server for health check

require 'rubygems'
require 'yaml'
require 'resolv'
require 'timeout'
require 'json'

#Temporary, require. These will be automatically passed in soon.

os_info=`lsb_release -a`.downcase + `uname`.downcase
if os_info =~ /ubuntu/
  ENV['RS_DISTRO']="ubuntu"
  apache="apache"
  ubuntu = true
  centos = false
elsif os_info =~ /centos/
  ENV['RS_DISTRO']="centos"
  apache="httpd"
  centos = true
  ubuntu = false
end

# Set the default port for the application server.
port = ENV['APP_PORT']

#Escape the 4 problematic shell characters: ", $, `, and \ to get through the ssh command correctly
def shell_escape(string)
  return string.gsub(/\\/,"\\\\\\").gsub(/\"/,"\\\"").gsub(/\$/,"\\\$").gsub(/\`/,"\\\\\`")
end

# Connect server machine to load balancer to start receiving traffic
applistener  = ENV['LB_APPLISTENER_NAME']
backend_name = ENV['LB_BACKEND_NAME']

case ENV['LB_BACKEND_IP']
when "private"
  this_backend = ENV['RS_PRIVATE_IP']
  puts "Registering the private ip: $this_backend"
when "public"
  this_backend = ENV['RS_PUBLIC_IP']
  puts "Registering the public ip: $this_backend"
else
  this_backend = ENV['RS_PRIVATE_IP']
  puts "Unknown IP type, using ip: #{this_backend}"
end

# Use cookies?
sess_sticky = "#{ENV['OPT_SESSION_STICKINESS']}".downcase
if(sess_sticky && sess_sticky.match(/^(true|yes|on)$/))
  cookie_options = "-c #{ENV['LB_BACKEND_NAME']}"
end

# How many conns do we tell the LB to bring to the AJP port?
max_conn_per_svr = ENV['MAX_CONN_PER_SERVER'] || 255

# Connect the app to all running instances of the lb host
addrs = Array.new
tag_query_output = `rs_tag --query "lb:set=#{ENV['LB_SET']}"`
puts "*** All LBs in the deployment tagged as part of the \"#{ENV['LB_SET']}\" lb set: #{tag_query_output}"
parsed_json= JSON.parse(tag_query_output)
parsed_json.each { |node|
  node[1]["tags"].each { |tag|
    if ( tag =~ /lb:ip=(.+)/ )
      addrs << $1
      puts "*** Found LB with IP: "+$1
    end
  }
}

puts "Found  #{addrs.length} addresses for lb set: #{ENV['LB_SET']}"
exit(-1) if addrs.length == 0 

successful=0
addrs.each do |addr| 
   begin
    addr_name=Resolv.getname(addr)
    addr_new=Resolv.getaddress(addr_name) if addr_name =~ /^ec2.*amazonaws.com$/
    addr=addr_new if addr_new =~ /^10\./
  rescue => e
    puts e.message+", moving on..."
  end
  puts ">>>>>>>Attaching app to host #{addr} <<<<<<<<<<<<<<"

  # Using the default config file...no cookie persistence...and health checks
  #/opt/rightscale/lb/bin/haproxy_config_server.rb  -a add -w -l $LB_APPLISTENER -s $LB_BACKEND_NAME -t $BACKEND_TARGET -k on -e "inter 3000 rise 2 fall 3 maxconn 3"
  sshcmd = "ssh -o StrictHostKeyChecking=no -o PasswordAuthentication=no root@#{addr}"
  cfg_cmd="/opt/rightscale/lb/bin/haproxy_config_server.rb"

  target="#{this_backend}:#{port}"
  args= "-a add -w -l \"#{applistener}\" -s \"#{backend_name}\" -t \"#{target}\" #{cookie_options} -e \" inter 3000 rise 2 fall 3 maxconn #{max_conn_per_svr}\" "
  args += " -k on " if ENV['HEALTH_CHECK_URI'] != nil && ENV['HEALTH_CHECK_URI'] != ""

  cmd = "#{sshcmd} #{cfg_cmd} #{shell_escape(args)}"
  puts cmd

  timeout=60*5 #@ 5min
  begin
    status = Timeout::timeout(timeout) do
     while true   
        response = `#{cmd}` 
    puts response #for debugging...
    break if response.include?("Haproxy restart sucessful")
        break if response.include?("Restart not required")
        puts "Retrying..."
        sleep 10
      end
    end
  rescue Timeout::Error => e
    puts "ERROR: Timeout after #{timeout/60} minutes."
    next
  end  
  
  successful += 1

end



if( successful != addrs.length )
  puts "Failure, only #{successful} out of #{addrs.length} lb hosts could be connected"
  exit(-1)
end