HEART is a rails engine to help you quickly begin visualizing your data as time series metrics.

Write your own metric definitions using your own Rails models and business logic. Use plain ole SQL, read in text files, make API calls, do whatever you need to get your metric values - and HEART will help you visualize it - no coding necessary.

Several display options are available for customizing bar and line graphs.

Other features include:

• shareable links direct to any graph you've viewed.
• export your graph to a saveable or hot-linkable image file.
• export your data to a tab-separated file for importing to Excel or other programs.
• Average and SUM your metric data with multiple different group by options
• annotate your graphs with notes on important dates
• create custom dashboards with all your favorite graphs for quick access
• visually compare year-on-year data
• track moving averages of your time series data
• easy to bundle and share metric definition code between projects

Inspiration for the original project, that eventually led to this open-source gem, was from the acronym H.E.A.R.T. (Happiness, Engagement, Adoption, Retention, Task-success) that was published in a whitepaper by Google employees (read it here: http://research.google.com/pubs/pub36299.html).

Watch this 11 minute video that shows how quick it is to go from a new rails app to graphing time-series data: http://youtu.be/iiYxqUeyAiQ

Add the gem to your gemfile:

gem 'heart', '~> 0.0.1'

[Optional] Add any other gems to your gemfile for prepackaged HEART metrics if applicable:

gem 'heart_vbulletin4', '~> 0.0.1'

Bundle, then migrate:

bundle install
bundle exec rake db:migrate

That will setup the HEART database tables, and add metrics for any prepackaged HEART metric gem that you might have installed.

Mount the engine on some path, by editing your routes.rb file and adding:

mount Heart::Engine => "/heart", as: 'heart_engine'

Now, when you startup your local server and access /heart you'll be greeted by the heart main page.

Need to add the following to your gem file for Rails 4 support:

gem 'protected_attributes'
gem 'haml', '~> 4.0'

The real simplicity of HEART comes from the ease in which you can create and isolate your own custom metrics to share between projects. Here's an example on how to add a metric to track the number of new posts in our imaginary forum which is written in Ruby on Rails (the same project we have the HEART gem installed in):

1. Create a 'heart' directory inside lib
2. Create a module in your lib directory to encase your metric definitions. The following example code would be placed in lib/heart/myforum.rb. (Note: All metric definitions can leverage the special fulldate method to allow HEART to pass in the current date it is trying to aggregate. )

  module Heart
    module Myforum
      # define a "fetch_camelCaseMetricName" method for your metric
      # recommend that you prefix your metric with the name of your module (e.g., myforum)
      def fetch_myforumPostsNew
        # set the myforumPostsNew attribute to some value, HEART will automatically save it
        self.myforumPostsNew = Myforum::Post.where(posted_at: Time.parse("#{fulldate} 00:00:00")..Time.parse("#{fulldate} 23:59:59")).count
      end
    end
  end

3. Create a migration to add your metric to HEART's database tables. Move the migration file into the same directory as your heart module. E.g., this file named 2013092100000123_add_posts_new_to_heart.rb is placed in the /lib/heart/ directory with the module created in step 2. (Note: All metrics need to migrate 2 tables 'heart_metrics' and 'heart_isometrics'. The heart_metrics field can be any type of integer, double, float; the heart_isometrics field must be the type datetime. HEART uses the heart_isometrics field internally to track the datetime that a particular metric's value was last aggregated, while the heart_metrics field is used to store the actual daily values. )

  class AddPostsNewToHeartMetrics < ActiveRecord::Migration
    def change
      add_column :heart_metrics, :myforumPostsNew, :integer
      add_column :heart_isometrics, :myforumPostsNew, :datetime
    end
  end

4. Run your migrations. HEART will automatically include the migration files in your lib/heart directory and its subdirectories (so you can arrange them in sub-folders however you like)
5. Aggregate your metric data into HEART's tables with the following rake task. This task will attempt to fetch and update all metric values between and including the dates you specify. Protip: call this command daily via a cron job to automatically aggregate all your metric data.

bundle exec rake heart:metrics:fetch_all fromdate=2013-09-01 todate=2013-09-03

6. For performance reasons, moving averages are also aggregated and cached in the database. To generate the cache of moving averages run the following. Protip: Automate this command via a cron job.

bundle exec rake heart:metrics:moving_average fromdate=2013-09-01 todate=2013-09-03 average=30

7. [Optional] If at some point you add a new metric or change the definition of a metric and would like to only update that metric's values, you can run the following rake task:

bundle exec rake heart:metrics:fetch_between fromdate=2010-12-01 todate=2011-01-01 metric=metricName

8. Add translations for your new metric(s). In the config/locales/en.yml add your translations under "en_heart". Translate both your metric and your module's name (which you hopefully prefixed with your module name) like the following:

  en_heart:
    myforum: "My Forum"
    myforumPostsNew: "New Posts"

All fetch methods must be prefixed with "fetch" followed by an underscore for HEART to find them. HEART takes the metric name from the database (e.g., "myforumPostsNew") and looks for a translation in your locales to pretty it up.

1. HEART in non-MySQL databases
2. Remove protected_attributes requirement for support Rails 4
3. Support time series for other than just daily values (e.g., hourly)