Track Rails errors with Sentry

Create Sentry project

Login to Sentry and go to Projects > Create project and choose the Rails project type.

Install gems

gem 'sentry-ruby'
gem 'sentry-rails'

Run:

./bin/bundle install

Configure Sentry

Create a file config/initializers/sentry.rb:

# frozen_string_literal: true

# https://docs.sentry.io/platforms/ruby/guides/rails/configuration/
Sentry.init do |config|
  config.breadcrumbs_logger = [:active_support_logger, :http_logger]
  config.traces_sample_rate = 0.25
end

Restart Rails server.

Verify setup

Each Sentry project is identified by a client key / DSN. We’ve omitted this from config/initializers/sentry.rb because we’ll provide it with the SENTRY_DSN environment variable instead.

To get the client key / DSN, navigate to Projects > [Project], click the cog icon on the top right and then Client Keys (DSN).

Normally, you’d set this in production or staging environment only but let’s test the Sentry integration locally.

Open up the Rails console:

SENTRY_DSN=<your-dsn> ./bin/rails console

Run:

Sentry.capture_message('test message')

You should see something like:

=> #<Sentry::Event @event_id="3e9672cb7cbd4abf8f3648cf80668700", @timestamp="2022-02-06T05:48:49Z", @platform=:ruby, @sdk={"name"=>"sentry.ruby", "version"=>"5.0.2"}, @user={}, @extra={}, @contexts={:os=>{:name=>"-ruby.rb:293", "sentry-ruby-core (5.0.2) lib/sentry/hub.rb:116"]>, @breadcrumbs=#<Sentry::BreadcrumbBuffer:0x00007fb2bbc590c0 @buffer=[nil, nil]>>
Sending envelope [event] 3e9672cb7cbd4abf8f3648cf80668700 to Sentry

This means Sentry was able to send the event to its servers. If you try this without setting the SENTRY_DSN env variable, you’ll get nil when you call Sentry.capture_message. Go to your Sentry project’s issues page and you should see the error reported.

Other notes

Sentry automatically sets the current environment to RAILS_ENV, or if it is not present, RACK_ENV.

Sources

• Sentry guide for Rails