Small ruby script to export PLATFORM_RELATIONSHIPS as pairs of key, value environment variables and runs the provided command

rels_to_env

#!/usr/bin/env ruby
require "base64"
require "json"

if ARGV.length != 3 then #expecting precisely 3 arguments
  puts "usage: rels_to_env [relationship name] [environment variable prefix] [start command]\n\nExample:\nexport_rels mysql DB \"java -jar myapp.jar\"\n\noutput:\nexport DB_HOST=\"database.internal\”\nexport DB_PORT=...\n" 
else
  rels = JSON.parse(Base64.decode64(ENV['PLATFORM_RELATIONSHIPS']))
  rel_name= ARGV[0]
  prefix = ARGV[1]
  puts "export #{prefix}_HOST=#{rels[rel_name][0]['host']}"
  puts "export #{prefix}_PORT=#{rels[rel_name][0]['port']}"
  puts "export #{prefix}_NAME=#{rels[rel_name][0]['path']}"
  puts "export #{prefix}_USERNAME=#{rels[rel_name][0]['username']}"
  puts "export #{prefix}_PASSWORD=#{rels[rel_name][0]['password']}"
  puts "export SERVER_PORT=#{ENV['PORT']}"
  exec ARGV[2]
end

usage: rels_to_env [relationship name] [environment variable prefix] [start command]

Example:
export_rels mysql DB "java -jar myapp.jar"

output:

export DB_HOST="database.internal”
export DB_PORT=...
export SERVER_PORT=8000
java -jar myapp.jar