initial import

rrstat.rb

@@ -0,0 +1,83 @@
+require 'redis'
+
+class RRStat
+  def initialize(opts)
+    @precision = opts[:precision]
+    @buckets = opts[:buckets]
+
+    @current = nil
+    @db = Redis.new
+  end
+
+  def time_epoch; Time.now.to_i / @buckets; end
+
+  def buckets(set)
+    (0...@buckets).inject([]) {|a,v| a.push "#{set}:#{(time_epoch - v)}" }
+  end
+
+  def epoch(set)
+    e = time_epoch
+    now = set + ":" + e.to_s
+
+    if now != @current
+      debug [:new_epoch, e]
+      @current = now
+
+      clear_bucket("#{set}:#{e - @buckets}")
+    end
+
+    @current
+  end
+
+  def union_epochs(set)
+    debug [:union_epochs, buckets(set)]
+    @db.zunion("#{set}:union", buckets(set))
+  end
+
+  def score(set, key)
+    union_epochs(set)
+
+    buckets(set).each {|b| debug [b, @db.zscore(b, key)]}
+    @db.zscore("#{set}:union", key).to_i
+  end
+
+  def incr(set, key, val=1)
+    debug [:zincrby, epoch(set), val, key]
+    @db.zincrby(epoch(set), val, key).to_i
+  end
+
+  def first(set, num, options = {})
+    union_epochs(set)
+    e = @db.zrevrange("#{set}:union", 0, num, options)
+    options.key?(:with_scores) ? Hash[*e] : e
+  end
+
+  def last(set, num, options = {})
+    union_epochs(set)
+    e = @db.zrange("#{set}:union", 0, num, options)
+    options.key?(:with_scores) ? Hash[*e] : e
+  end
+
+  def delete(set, key)
+    buckets(set).each do |b|
+      @db.zrem(b, key)
+    end
+  end
+
+  def clear(set)
+    buckets(set).each do |b|
+      clear_bucket(b)
+    end
+  end
+
+  def flushdb; @db.flushdb; end
+
+  private
+
+    def clear_bucket(b)
+      debug [:clearing_epoch, b]
+      @db.zremrangebyrank(b, 0, 2**32)
+    end
+
+    def debug(msg); p msg; end
+end

spec/rrstat_spec.rb

@@ -0,0 +1,92 @@
+require 'spec'
+require 'delorean'
+require 'rrstat'
+require 'time'
+
+describe RRStat do
+  include Delorean
+
+  let(:rr) { RRStat.new(:precision => 10, :buckets => 6) }
+
+  before(:each) { time_travel_to("Jan 1 2010") }
+  before(:each) { rr.flushdb }
+
+  it "should initialize db" do
+    lambda {
+      RRStat.new(:precision => 10, :buckets => 6)
+    }.should_not raise_error
+  end
+
+  it "should return score of item" do
+    rr.score("test", "random_key").should == 0
+  end
+
+  it "should increment buckets within correct epoch" do
+    rr.epoch("test").should match(/test:210394200/)
+
+    rr.incr("test", "key")
+    rr.score("test", "key").should == 1
+
+    rr.incr("test", "key", 2)
+    rr.score("test", "key").should == 3
+
+    # advance to next epoch
+    time_travel_to(Time.now + 10) do
+      rr.epoch("test").should match(/test:210394201/)
+
+      rr.incr("test", "key")
+      rr.score("test", "key").should == 4
+    end
+
+    # advance 5 epochs, to scroll original incr's off the list
+    time_travel_to(Time.now + 40) do
+      rr.epoch("test").should match(/test:210394206/)
+
+      rr.incr("test", "key")
+      rr.score("test", "key").should == 2
+    end
+  end
+
+  it "should return top N items from all epochs" do
+    rr.incr("test", "key1", 1)
+    rr.incr("test", "key2", 3)
+
+    # advance to next epoch
+    time_travel_to(Time.now + 10) do
+      rr.epoch("test").should match(/test:210394201/)
+      rr.incr("test", "key3", 5)
+
+      rr.first("test", 3).should == ["key3", "key2", "key1"]
+      rr.first("test", 3, :with_scores => true).should == {"key3"=>"5", "key2"=>"3", "key1"=>"1"}
+    end
+  end
+
+  it "should return last N items from all epochs" do
+    rr.incr("test", "key1", 1)
+    rr.incr("test", "key2", 3)
+
+    # advance to next epoch
+    time_travel_to(Time.now + 10) do
+      rr.epoch("test").should match(/test:210394201/)
+      rr.incr("test", "key3", 5)
+
+      rr.last("test", 3).should == ["key1", "key2", "key3"]
+      rr.last("test", 3, :with_scores => true).should == {"key1"=>"1", "key2"=>"3", "key3"=>"5"}
+    end
+  end
+
+  it "should erase key from all epochs" do
+    rr.incr("test", "key", 1)
+    rr.score("test", "key").should == 1
+
+    # advance to next epoch
+    time_travel_to(Time.now + 10) do
+      rr.epoch("test").should match(/test:210394201/)
+      rr.incr("test", "key")
+      rr.score("test", "key").should == 2
+
+      rr.delete("test", "key")
+      rr.score("test", "key").should == 0
+    end
+  end
+end