Strumbar

Strumbar is a wrapper around ActiveSupport::Notifications with preconfigurations for basic instrumentation to be sent to statsd.

Installation

Add this line to your application's Gemfile:

gem 'strumbar'

And then execute:

$ bundle

Or install it yourself as:

$ gem install strumbar

Usage

Configuration (all options shown with default values):

Strumbar.configure do |config|

  # Application name as it should be stored by your Statsd backend.
  config.application = 'statsd_appname'

  # Statsd hostname
  config.host = 'statsd.appname.example'

  # Statsd port
  config.port = 8125

  # Default sample rate for all events.
  config.default_rate = 1

end

Adding this alone causes basic instrumentation data to be sent to the Statsd server broken down by your application and will be visible in the dashboard. If you are happy with that, you're done. Adding custom instrumentation that is specific to your application is incredibly simple. Strumbar is a wrapper around ActiveSupport::Notifications.

Strumbar.subscribe /something_cool/ do |client, event|
  client.increment 'something_cool_counter'
end

Client is an instance of Strumbar::Client and wraps around Statsd::Client for namespacing and syntactic sugar.

By default, it will subscribe to runtime data for process_action.action_controller and the sql load time in sql.active_record.

In case you get tired of typing ActiveSupport::Notifications.instrument you can use the helpful sugar Strumbar provides:

Strumbar.strum 'view.render', payload do
  render :text => "I'm monitored!"
end

Default Instruments

Strumbar takes the approach of auto-detecting the libraries being used and loading default instrumentation subscriptions. Currently, this list includes:

• ActionController
• ActiveRecord
• Redis

Alternatively, you can choose specific instrumentations to load and set your own sample rates for each by passing a block to config.instrumentation, like so:

Strumbar.configure do |config|
  config.instrumentation do
    Strumbar::Instrumentation::ActionController.load rate: 0.5
    Strumbar::Instrumentation::ActiveRecord.load
    Strumbar::Instrumentation::Redis.load

    AppName::Instrumentation::ThirdPartyInstrument.load rate: 0.8
  end
end

## Authors

Written by [Andrew Nordman](https://github.com/cadwallion) and [Matthew Wilson](https://github.com/hypomodern)