counter

Count things and rank them, as a one-off or over time.

Major components:

  • Counter - a simple class to track counts, then sort and rank

  • MovingCount - a base class built atop ActiveRecord to aggregate counts over time (think rrdtool for counts)

Getting started

gem install counter
config.gem 'counter'

require 'counter'

To use MovingCount, you’ll also need to

require 'counter/moving_count'

(separate to prevent ActiveRecord dependency pollution)

Counter

c = Counter.new

# Counts can be incremented as a key appears
c.increment('some-key')
c.increment('some-key')

# Or set directly
c.set('another-key', 42)

# You can retrieve all
c.counts
=> [['another-key',42],['some-key',2]]

# Or just the top-n
c.top(1)
=> [['another-key',42]]

See Counter docs for detail.

MovingCount

require 'counter/moving_count'
class PageView < MovingCount
end

# In a migration:
#  create_table :page_views, :force => true do |t|
#    t.string   :category,      :null => false
#    t.integer  :count,         :null => false, :default => 0
#    t.datetime :sample_time,   :null => false
#  end
#
#  add_index :page_views, :category

# First set of samples...
PageView.record_counts(Time.now - 5.minutes) do |c|
  c.increment('a-key')
  c.increment('a-key')
end

# Second set...
PageView.record_counts(Time.now) do |c|
  c.increment('a-key')
  c.increment('another-key')
end

# Both contribute to totals grouped by category.
PageView.totals
=> [['a-key',3],['another-key',1]]

# Get the grand total across all categories.
PageView.grand_total
=> 4

See MovingCount docs for detail (filters available on totals to limit results).

Author

Ben Koski, [email protected]

Copyright © 2010 The New York Times Company. See LICENSE for details.