Install redis from ruby code

install_redis.rb

def which(cmd)
  exts = ENV['PATHEXT'] ? ENV['PATHEXT'].split(';') : ['']
  ENV['PATH'].split(File::PATH_SEPARATOR).each do |path|
    exts.each do |ext|
      exe = File.join(path, "#{cmd}#{ext}")
      return exe if File.executable?(exe) && !File.directory?(exe)
    end
  end
  nil
end

puts "== Installing redis =="
if which("brew")
  puts "Found brew 🍺"
  redis = `brew ls --versions redis`
  if !redis.empty?
    puts("Redis is already installed. Versions:\n#{redis}")
  else
    system! "brew install redis"
  end
else
  redis = which("redis-server")
  if redis
    puts "Found redis in #{redis}"
  else
    puts "Manually installing redis..."
    chdir "tmp/" do
      system! "curl -O http://download.redis.io/redis-stable.tar.gz"
      system! "tar -xvzf redis-stable.tar.gz"
      chdir "redis-stable/" do
        puts "Require sudo for make install"
        system! "make && sudo make install"
      puts "Redis installed! Located in: #{which "redis-server"}"
      end
    end
  end
end