Exception Notifier Plugin for Rails

The Exception Notifier plugin provides a mailer object and a default set of templates for sending email notifications when errors occur in a Rails application. The plugin is configurable, allowing programmers to specify:

the sender address of the email
the recipient addresses
the text used to prefix the subject line

The email includes information about the current request, session, and environment, and also gives a backtrace of the exception.

Installation

You can use the latest ExceptionNotification gem with Rails 3, by adding the following line in your Gemfile

gem 'exception_notification'

As of Rails 3 ExceptionNotification is used as a rack middleware, so you can configure its options on your config.ru file, or in the environment you want it to run. In most cases you would want ExceptionNotification to run on production. You can make it work by

Whatever::Application.config.middleware.use ExceptionNotifier,
  :email_prefix => "[Whatever] ",
  :sender_address => %{"notifier" <[email protected]>},
  :exception_recipients => %w{[email protected]}

Customization

By default, the notification email includes four parts: request, session, environment, and backtrace (in that order). You can customize how each of those sections are rendered by placing a partial named for that part in your app/views/exception_notifier directory (e.g., _session.rhtml). Each partial has access to the following variables:

@controller     # the controller that caused the error
@request        # the current request object
@exception      # the exception that was raised
@backtrace      # a sanitized version of the exception's backtrace
@data           # a hash of optional data values that were passed to the notifier
@sections       # the array of sections to include in the email

You can reorder the sections, or exclude sections completely, by altering the ExceptionNotifier.sections variable. You can even add new sections that describe application-specific data--just add the section's name to the list (wherever you'd like), and define the corresponding partial.

#Example with two new added sections
Whatever::Application.config.middleware.use ExceptionNotifier,
   :email_prefix => "[Whatever] ",
   :sender_address => %{"notifier" <[email protected]>},
   :exception_recipients => %w{[email protected]},
   :sections => %w{my_section1 my_section2} + ExceptionNotifier::Notifier.default_sections

If your new section requires information that isn't available by default, make sure it is made available to the email using the exception_data macro:

class ApplicationController < ActionController::Base
  before_filter :log_additional_data
  ...
  protected
    def log_additional_data
      request.env["exception_notifier.exception_data"] = {
        :document => @document,
        :person => @person
      }
    end
  ...
end

In the above case, @document and @person would be made available to the email renderer, allowing your new section(s) to access and display them. See the existing sections defined by the plugin for examples of how to write your own.

Background Notifications

If you want to send notifications from a background process like DelayedJob, you should use the background_exception_notification method like this:

begin
  some code...
rescue => e
  ExceptionNotifier::Notifier.background_exception_notification(e)
end

Manually notify of exception

If your controller action manually handles an error, the notifier will never be run. To manually notify of an error you can do something like the following:

rescue_from Exception, :with => :server_error

def server_error(exception)
  # Whatever code that handles the exception

  ExceptionNotifier::Notifier.exception_notification(request.env, exception).deliver
end

Notification

After an exception notification has been delivered the rack environment variable 'exception_notifier.delivered' will be set to +true+.

Rails 2.3 stable and earlier

If you are running Rails 2.3 then see the branch for that:

http://github.com/smartinez87/exception_notification/tree/2-3-stable

If you are running pre-rack Rails then see this tag:

http://github.com/smartinez87/exception_notification/tree/pre-2-3

Support and tickets

https://github.com/smartinez87/exception_notification/issues