Have you ever wanted to be one step ahead of your users, and be notified of any unwanted exception before anyone? If so, read this article to configure your rails application in just a few steps.

First, we are going to need two gems:

  • Exception Notification, provides a set of notifiers for sending notifications when errors occur in a Rack/Rails application
  • Slack-Notifier, a simple wrapper to send notifications to Slack webhooks.

Install them as you would do with any other gem. In my case, I add them to the Gemfile and then run bundle install

Setting them up is as easy as adding a few lines in our environment files, or in a initializer config file:

Rails.application.config.middleware.use ExceptionNotification::Rack,
      :slack {
        :webhook_url = "YOUR_WEB_HOOK_URL"

But wait, how do I get that YOUR_SLACK_WEB_HOOK_URL??

  1. Go to https://slack.com/apps/A0F7XDUAZ-incoming-webhooks
  2. Once you have logged in into your team, on the left-side panel, choose “Add Configuration”
  3. Select the Slack channel where you want to get notified, and then press “Add Incoming WebHooks integration”
  4. You will see a Webhook URL like https://hooks.slack.com/services/XXXXXXXX/XXXXXXXXXXXXXXXXXXXXXXXX

OK, that was easy, but how can I test that it is working??

I know, your code is so perfect that it doesn’t raise any exception. In that case, we can add a rails route, to test this functionality.

Go to your routes.rb file and add this:

# Route for testing Exception Notification configuration
get "test_exception_notifier" => "application#test_exception_notifier"

Then, in your application controller:

def test_exception_notifier
   raise "Test Exception. This is a test exception to make sure the exception notifier is working."

Finally, just visit yourhost/test_exception_notifier and voila! you should receive a slack notification looking something like this:

Slack notification example

Slack notification example

In the message you will get a full detail of the exception, including a description, the host name and a full backtrace.

Let us know how this worked for you in the comments!