Script to easily add/remove custom environment variables (env.custom) on all instances

ey_env_var.rb

#!/usr/bin/env ruby

# Usage:
#  Add env variable: /path/to/this/script {environment} add VAR_NAME varvalue
#  Remove env variable: /path/to/this/script {environment} remove VAR_NAME

require 'active_support'

app_name = "betterdoc"

ENV_NAME = ARGV[0].to_s
action = ARGV[1].to_s
var_key = ARGV[2].to_s
var_value = ARGV[3].to_s

def msg(text)
  puts "----> #{text}"
end

def run(cmd)
  puts "* #{cmd}\n\n"
  `#{cmd}`
end

def run_ssh(cmd)
  full_cmd = "ey ssh '#{cmd}' -e #{ENV_NAME}"
  run(full_cmd).gsub("Loading application data from Engine Yard Cloud...", "")
end

msg "Getting current env variables"
env_custom_string = run_ssh("cat /data/#{app_name}/shared/config/env.custom")
env_vars = env_custom_string.split("\n").select { |l| l.match(/^export/) }.inject({}) do |hash,line|
  key, value = line.gsub("export", "").strip.split("=")
  hash.merge(key => value)
end

if action == "add" && !var_key.empty? && !var_value.empty?
  env_vars[var_key] = var_value
elsif action == "remove" && !var_key.empty?
  env_vars.delete(var_key)
else
  raise "Unknown action '#{action}' or missing key '#{var_key}' or value '#{var_value}'"
end

File.open("env.custom", "w") do |f|
  env_vars.keys.sort.each do |key|
    f.write "export #{key}=#{env_vars[key]}\n"
  end
end

msg "Getting dna from engineyard"
chef_dna = run_ssh("sudo cat /etc/chef/dna.json")
dna = ActiveSupport::JSON.decode(chef_dna)

instances = dna['engineyard']['environment']['instances']

instances.each do |instance|
  msg "Updating #{instance['name'] || 'application'} instance"
  run "scp env.custom deploy@#{instance['public_hostname']}:/data/#{app_name}/shared/config/env.custom"
end

msg "Removing tmp env.custom file"
run "rm env.custom"

msg "[IMPORTANT NOTE] To restart web (unicorn) server run: ey ssh '/engineyard/bin/app_#{app_name} reload' -e #{ENV_NAME}"