ScoutDogstatsd

Want your Rails performance KPIs in your DogStatsD-compatible metric system with almost zero effort? Of course you do! Meet scout_dogstatsd! This gem is an extension of the Scout Ruby monitoring agent (scout_apm), and makes it easy to create an app performance dashboard:

A Scout account isn’t required, but it certainly makes getting to the source of app performance easier 😉.

Using plain-vanilla StatsD? Checkout scout_statsd_ruby.

Metrics

The following metrics are reported w/o any custom instrumentation steps:

Metric Name	Type	Description
web.duration_ms	histogram	The total duration of web requests in milliseconds
job.duration_ms	histogram	The total duration of background jobs (Sidekiq, DelayedJob, etc.) in milliseconds
web.error_count	counter	A count of web requests that throw an exception
job.error_count	counter	A count of background jobs that throw an exception
web.queue_time_ms	gauge	The time spent in request queuing in milliseconds
job.queue_time_ms	gauge	The time between when a job is inserted into a background job queue and when execution begins in milliseconds

Tags

These metrics are tagged too! Slice and dice! The following tags are added to each metric:

Tag Name	Description
app	The name of the app. See the name Scout config option.
hostname	The hostname of the app. See the hostname Scout config option.

Now, you can correlate app performance metrics with all of your other system metrics.

Monitoring Platforms that Support the DogStatsD Protocol

• DataDog
• SignalFx via the collectd dogstatsd plugin
• Prometheus via the statsd exporter

Installation

Add this line to your application’s Gemfile:

gem 'scout_dogstatsd'

And then execute:

$ bundle

Or install it yourself as:

$ gem install scout_dogstatsd

Configuration

1. Add a config/initializers/scout_dogstatsd.rb file to your Rails app:

require 'datadog/statsd'
statsd = Datadog::Statsd.new('localhost', 8125)
ScoutDogstatsd.configure(statsd)

2. Add a config/scout_apm.yml file to your Rails app:

This step isn’t required if you are already using Scout.

common: &defaults
  monitor: true

development:
  <<: *defaults
  monitor: false # set to true to test in your development environment

production:
  <<: *defaults

Metrics are only sent if monitor: true for the associated Rails environment.

See the Scout docs for advanced configuration instructions.

How it works

After each transaction (a web request or background job), the metrics specific to that transaction are transmitted via the DogStatsD protocol via the client passed through to ScoutDogstatsd#configure. No code changes are required: the scout_apm gem automatically instruments Rails controller-actions and background jobs. Easy peasy!

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/scoutapp/scout_dogstatsd_ruby.

License

The gem is available as open source under the terms of the MIT License.