Redis Counters

redis_counter.rb

module RedisCounter

  # increment counters
  def self.incr(name, uniq_key=nil)
    time = Time.now

    REDIS.multi do |r|
      key_names.each do |key_name|
        # count
        incr_key = send("#{key_name}_key", name, time)
        REDIS.incr(incr_key)

        # uniq count
        if uniq_key
          set_key = send("#{key_name}_key", "#{name}:uniq", time)
          REDIS.sadd(set_key, uniq_key)
        end
      end
    end
  end

  # return counts for the given time
  def self.counts(name, time=Time.now)
    {
      :total => get_counts(name, "total", time),
      :year => get_counts(name, "year", time),
      :month => get_counts(name, "month", time),
      :day => get_counts(name, "day", time),
      :hour => get_counts(name, "hour", time),
      :min => get_counts(name, "min", time),
      :sec => get_counts(name, "sec", time)
    }
  end


  private

  def self.get_counts(name, precision, time)
    count = count(name, precision, time)
    uniq = count_uniq(name, precision, time)
    avg = uniq > 0 ? (count/uniq) : 0

    {
      :count => count,
      :uniq => uniq,
      :avg => avg
    }
  end

  def self.count(name, precision, time)
    key = send("#{precision}_key", name, time)

    REDIS.get(key).to_i
  end

  def self.count_uniq(name, precision, time)
    key = send("#{precision}_key", "#{name}:uniq", time)

    REDIS.scard(key).to_i
  end

  def self.key_names
    [
      "total",
      "year",
      "month",
      "day",
      "hour",
      "min",
      "sec"
    ]
  end

  def self.total_key(name, time)
    ["peelr", name].join(":")
  end

  def self.year_key(name, time)
    [total_key(name, time), time.year].join(":")
  end

  def self.month_key(name, time)
    [year_key(name, time), time.month].join(":")
  end

  def self.day_key(name, time)
    [month_key(name, time), time.day].join(":")
  end

  def self.hour_key(name, time)
    [day_key(name, time), time.hour].join(":")
  end

  def self.min_key(name, time)
    [hour_key(name, time), time.min].join(":")
  end

  def self.sec_key(name, time)
    [min_key(name, time), time.sec].join(":")
  end

end