gitlab-org--gitlab-foss/doc/telemetry/backend.md

Backend tracking guide

GitLab provides Gitlab::Tracking, an interface that wraps the Snowplow Ruby Tracker for tracking custom events.

Tracking in Ruby

Custom event tracking and instrumentation can be added by directly calling the GitLab::Tracking.event class method, which accepts the following arguments:

argument	type	default value	description
category	string	'application'	Area or aspect of the application. This could be HealthCheckController or Lfs::FileTransformer for instance.
action	string	'generic'	The action being taken, which can be anything from a controller action like create to something like an Active Record callback.
data	object	{}	Additional data such as label, property, value, and context as described in our Feature Instrumentation taxonomy. These will be set as empty strings if you don't provide them.

Tracking can be viewed as either tracking user behavior, or can be utilized for instrumentation to monitor and visual performance over time in an area or aspect of code.

For example:

class Projects::CreateService < BaseService
  def execute
    project = Project.create(params)

    Gitlab::Tracking.event('Projects::CreateService', 'create_project',
      label: project.errors.full_messages.to_sentence,
      value: project.valid?
    )
  end
end

Performance

We use the AsyncEmitter when tracking events, which allows for instrumentation calls to be run in a background thread. This is still an active area of development.