redis-trim-aof.rb

#!/usr/bin/env ruby
# Script to remove commands from an AOF. Writes trimmed down AOF
# to standard out. Progress report is written to standard error.
#
# Usage: redis-trim-aof.rb <appendonly.aof> [regexp ...]
# Example: redis-trim.aof.rb myaof.aof ^user:\\d+ > newaof.aof
#
# Note: make sure to provide enough escape characters for special
# characters inside the regexp (because a regular shell also does
# escaping of characters).
#
require 'stringio'

class Command
  attr_accessor :argc, :argv

  def initialize(io)
    self.argc = io.gets.strip[/^\*(\d+)$/,1].to_i
    self.argv = []
    argc.times {
      bytes = io.gets.strip[/^\$(\d+)$/,1].to_i
      self.argv << io.read(bytes)
      io.read(2) # consume \r\n
    }
  end
  
  def match?(rgxs)
    rgxs.any? { |r| r.match(argv[1]) }
  end

  def to_s
    out = "*#{argv.size}\r\n"
    argv.each { |arg|
      out << "$#{arg.size}\r\n"
      out << arg
      out << "\r\n"
    }
    out
  end
end

f = File.open(ARGV[0],'r')
fs = File.size(ARGV[0])
skip = ARGV[1..-1].map { |arg| Regexp.new(arg) }
while !f.eof?
  cmd = Command.new(f)
  if !cmd.match?(skip)
    STDOUT.print cmd.to_s
  end

  pct = f.pos.to_f / fs
  STDERR.print "\r%6.2f%%" % (pct * 100)
end