Delete large Redis lists with Ruby and Resque

gistfile1.rb

$redis = Redis.new

class SafeListDelete
  @queue = :garbage_collection

  BATCH_SIZE = 100

  # Rename the key and queue for deletion
  def self.delete(key)
    newkey = "gc:lists:#{$redis.incr("gc:index")}"
    $redis.rename(key, newkey)
    Resque.enqueue(self, newkey)
  end

  # Trim off elements in batches
  def self.perform(key)
    while $redis.llen(key) > 0
      $redis.ltrim(key, 0, -BATCH_SIZE - 1)
    end
  end
end

# Example:
#
#   SafeListDelete.delete("my.large.list")