Exception Monitoring¶

This will provide some guidelines for adding exception monitoring to your application using our Sentry subscription.

What software needs Exception Monitoring¶

In general, all of the deployed custom software we write should have exception monitoring. If a product is no longer being maintained and we are actively moving to replace or retire it, exception monitoring should probably not be included.

What are we using for Exception Monitoring¶

Sentry

How do I get an account?¶

The accounts are maintained by EngX, so ask in our channel on the #engineering Slack channel if don’t yet have a Sentry login to our account.

How can I add Sentry to my application¶

From the main MIT Libraries Sentry page, choose “Add New > Project”
Choose the language for some general instructions and useful provide a name for the project
Follow the instructions that are provided by Sentry (NOTE: see below for some language specific tips we’ve come up with beyond the official documentation)

How can I add Sentry to my Rails application¶

For most Rails application needs:

Create a project for your application in Sentry.
Add SENTRY_DSN to your ENV. Set the value to whatever the project you just created provides.
Add SENTRY_ENV to your ENV. The value for this variable depends on which instance of your application you’re configuring. For example, pr (for pipelines), staging, dev, and prod are all acceptable values.
Add the Sentry gems to your Gemfile:

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

Create a a Sentry initializer in config/initializers/sentry.rb:

Sentry.init do |config|
  return unless ENV.has_key?('SENTRY_DSN')
  config.dsn = ENV.fetch('SENTRY_DSN')
  config.breadcrumbs_logger = [:active_support_logger, :http_logger]
  config.environment = ENV.fetch('SENTRY_ENV', 'unknown')
end

Run the app and exceptions will be shipped to Sentry automatically with no additional initialization required. You can test that it’s working by sending a message from the console like this: Sentry.capture_message('test').

How can I add Sentry to my JavaScript features in my Rails application¶

Obtain a sentry js style DSN key by going to https://docs.sentry.io/clients/javascript/ and select your application from the configuration dropdown under “Configuring the Client”
NOTE: do not use the DSN you used for your Rails application, it is important you use the specific JS key as it will be publicly shared unlike your Rails DSN.
set JS_EXCEPTION_LOGGER_KEY value to the project specific JavaScript DSN in your ENV
Include something like the following in your application template:

<% if ENV['JS_EXCEPTION_LOGGER_KEY'].present? %>
  <script src="https://cdn.ravenjs.com/3.25.2/raven.min.js" crossorigin="anonymous"></script>
  <script>Raven.config('<%= ENV['JS_EXCEPTION_LOGGER_KEY'] %>').install()</script>
<% end %>

How can I add Sentry to my Python application¶

For both Django and Flask, add SENTRY_DSN to your ENV and set this to whatever value the project you just created provides.

Django¶

pipenv install sentry-sdk
Add the following to your production settings file:

import os
import sentry_sdk
from sentry_sdk.integrations.django import DjangoIntegration

sentry_sdk.init(
    dsn="os.getenv(SENTRY_DSN)",
    integrations=[DjangoIntegration()]
)

For more info, check out the Sentry Django setup docs

Flask¶

pipenv install sentry-sdk[flask]
Add the following to your production settings file:

import os
import sentry_sdk
from sentry_sdk.integrations.flask import FlaskIntegration

sentry_sdk.init(
    dsn="os.getenv(SENTRY_DSN)",
    integrations=[FlaskIntegration()]
)

app = Flask(__name__)

For more info, check out the Sentry Flask setup docs

How can I add Sentry to my PHP application¶

There is a Sentry PHP library that will do most of the work for you. Depending on what PHP framework you are using, the final integration will vary.

Drupal¶

Sentry integration within Drupal is provided via Raven.

For Drupal 8, add Raven via composer require drupal/raven, which will install both Raven and the Sentry PHP library.

For Drupal 7, you will need X Autoload and the Libraries API. Additionally, you will need to place the Sentry PHP library at /sites/all/libraries/sentry-php/ so that the path to the client is /sites/all/libraries/sentry-php/lib/Raven/Client.php.

After installing, log into the Drupal application to configure the DSN and other settings at /admin/config/development/raven.

WordPress¶

Sentry integration within WordPress is provided via WP Sentry Integration.

Further WordPress instructions will be available soon.