This add-on is operated by Terrible Labs

Capture and analyze validation errors from your Rails app.


Last Updated: 07 May 2015

addons beta

The Guardrail add-on is currently in beta.

Table of Contents

Guardrail captures validation errors from your Ruby on Rails application to help you identify and fix user experience issues.

Deploying to Heroku

To use Guardrail on Heroku, install the guardrail add-on:

$ heroku addons:create guardrail

Rails setup

Rails 3+

Add the following line to your app’s Gemfile:

gem 'guardrail_notifier'

Install the gem:

$ bundle install

Rails 2.3.x

Install the gem:

$ gem install guardrail_notifier

Add the following line to config/environment.rb:

config.gem 'guardrail_notifier'

The gem will detect ENV['GUARDRAIL_API_KEY'] in your Heroku environment, so no further configuration is needed. However, there are some advanced options you may want to configure.

Advanced usage

Filtering params

GuardrailNotifier records the parameters submitted in actions that cause validation errors. Because your app may handle sensitive data, like passwords, credit card numbers, and nuclear launch codes, GuardrailNotifier respects the built-in Rails parameter filtering that you define with config.filter_parameters (or filter_parameter_logging in Rails 2.3). For example, in Rails 3’s application.rb:

config.filter_parameters << [:password, :secret]

Per Rails convention, any params that match ‘password’ or ‘secret’ will show up as “[FILTERED]” in the data submitted to Guardrail.

Tracking custom actions

GuardrailNotifier assumes your app is RESTful, so it only monitors the create and update actions by default. If you’re creating or updating records in non-RESTful actions, you can use an after_filter to make sure any validation failures in those actions are caught as well:

after_filter :log_validation_failures_to_guardrail, :only => [:create, :update, :my_custom_action]

Running in other environments

GuardrailNotifier is only enabled in the production environment by default. If you want to enable it in additional environments, such as staging, you’ll need to add the following to config/initializers/guardrail_notifier.rb:

GuardrailNotifier.configure do |config|
  config.monitored_environments << 'staging'


GuardrailNotifier submits errors with SSL by default, but you can disable it easily in an initializer:

GuardrailNotifier.configure do |config| = false

Further reading