redis pipe inputter for getting simple S3 key list into redis quickly

redis_piper.rb

!/usr/bin/env ruby
#
# use this to bulk load s3 keys into redis.
#
# usage:
# ------
#
#   cat /root/s3.keys | redis_piper.py | redis-cli -h HOST -n DB --pipe
#

def gen_redis_proto(*cmd)
    proto = ""
    proto << "*"+cmd.length.to_s+"\r\n"
    cmd.each{|arg|
        proto << "$"+arg.to_s.bytesize.to_s+"\r\n"
        proto << arg.to_s+"\r\n"
    }
    proto
end

ARGF.each do |line|
  key = line.strip
  STDOUT.write(gen_redis_proto("SETNX", key, 1))
end