exception_notification-rake - ExceptionNotifier for Rake tasks

This Ruby gem is an extension of the exception_notification gem to support sending mail (or other sorts of notifications) upon failures in Rake tasks. This is useful if you run Rake tasks as batch jobs on a schedule, particularly if you're using the Heroku Scheduler add-on.

Installation

If you're using Rails 4.2, 5 or 6 (or you're not using Rails at all), use the latest version of the gem:

gem 'exception_notification-rake', '~> 0.3.1'

If you're using Rails 4.1.x, use the 0.2.x line of versions:

gem 'exception_notification-rake', '~> 0.2.2'

If you're using Rails 4.0.x, use the 0.1.x line of versions:

gem 'exception_notification-rake', '~> 0.1.3'

If you're using Rails 3, use the 0.0.x line of versions:

gem 'exception_notification-rake', '~> 0.0.7'

Usage

Configuration for Email Notifications

Note: These examples are for the latest version of the gem (using exception_notification 4+ and Rails 4+). For a Rails 3.2 example see below.

Exception notification must be set up in your Rails config files. In general, you'll want to do this in environment-specific config files, such as config/environments/production.rb. Minimal configuration:

# config/environments/production.rb

YourApp::Application.configure do
  # Other configuration here, including ActionMailer config ...

  config.middleware.use ExceptionNotification::Rack,
    :ignore_if => lambda { |env, exception| !env.nil? },
    :email => {
      :sender_address => %{"notifier" <sender.address@example.com>},
      :exception_recipients => %w{your.email@example.com}
    }

  ExceptionNotifier::Rake.configure
end

Note: This uses :ignore_if to suppress all exception notifications not triggered by a background exception (identified by a nil environment). If you want to see all notifications (i.e., also those triggered by requests to the Rails server), omit the :ignore_if option.

If you are already using ExceptionNotifier anyway, you don't need to configure it again and all you need is:

# config/environments/production.rb

YourApp::Application.configure do
  # Other configuration here, including ExceptionNotifer and ActionMailer config ...

  ExceptionNotifier::Rake.configure
end

Note: As a prerequisite for sending mail your Rails Action Mailer needs to be configured in the environment where you're using exception notification. See the Rails guide on Action Mailer.

Other Notifiers

exception_notificatons supports a bunch of notifiers other than email. See its documentation for details. This gem should generally work out of the box with all notifiers. The Rake command line that led to the failure is available at the :rake_command_line key in the data dictionary.

Rails 3.2 Configuration Example

# config/environments/production.rb

YourApp::Application.configure do
  # Other configuration here, including ActionMailer config ...

  config.middleware.use ExceptionNotifier,
    :sender_address       => %{"notifier" <sender.address@example.com>},
    :exception_recipients => %w{your.email@example.com},
    :ignore_if            => lambda { true }

  ExceptionNotifier::Rake.configure
end

For complete documentation on the Rails 3.2 version see the corresponding branch on GitHub.

Email Notification Example

Email sent upon a failure will include the Rake tasks executed and a stacktrace. This is the result from calling an undefined method khaaaaan! in a task called failing_task (the data section contains the executed Rake command line in the :rake_command_line key):

Subject: [ERROR] (NoMethodError) "undefined method `khaaaaan!' for main:Object"
From: "notifier" <sender.address@example.com>
To: <your.email@example.com>

A NoMethodError occurred in background at 2014-07-20 21:25:00 UTC :

  undefined method `khaaaaan!' for main:Object
  /Users/haldimann/Projects/nikhaldimann.com/lib/tasks/scheduler.rake:33:in `block in <top (required)>'

-------------------------------
Backtrace:
-------------------------------

  lib/tasks/scheduler.rake:33:in `block in <top (required)>'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/task.rb:240:in `call'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/task.rb:240:in `block in execute'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/task.rb:235:in `each'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/task.rb:235:in `execute'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/task.rb:179:in `block in invoke_with_call_chain'
  .rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/task.rb:172:in `invoke_with_call_chain'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/task.rb:165:in `invoke'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:150:in `invoke_task'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:106:in `block (2 levels) in top_level'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:106:in `each'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:106:in `block in top_level'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:115:in `run_with_threads'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:100:in `top_level'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:78:in `block in run'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:176:in `standard_exception_handling'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/lib/rake/application.rb:75:in `run'
  .rvm/gems/ruby-1.9.3-p327/gems/rake-10.3.2/bin/rake:33:in `<top (required)>'
  .rvm/gems/ruby-1.9.3-p327/bin/rake:19:in `load'
  .rvm/gems/ruby-1.9.3-p327/bin/rake:19:in `<main>'
  .rvm/gems/ruby-1.9.3-p327/bin/ruby_noexec_wrapper:14:in `eval'
  .rvm/gems/ruby-1.9.3-p327/bin/ruby_noexec_wrapper:14:in `<main>'

-------------------------------
Data:
-------------------------------

  * data: {:rake_command_line=>"rake failing_task"}

Usage with Heroku Scheduler

If you're using Heroku, the Scheduler add-on is a very convenient and cheap way to run scheduled batch jobs. In a Rails environment it's easiest to define batch jobs as Rake tasks. However, the only way to find out whether a task run by the scheduler succeeded or failed is generally reading the logs.

This gem fixes this issue. Here is a detailed guide about configuring it on Heroku. In summary: If you configure exception notification as described above it should work out of the box with the Heroku Scheduler. (Provided you have email delivery set up in your Heroku app - you could try the SendGrid add-on which comes in a free version that should be good enough for notifications.)

Customization

You can pass configuration options to ExceptionNotifier::Rake.configure. These will be passed through to each notifier you configured with ExceptionNotifier (see its documentation for details on options). The options will be applied only to notifications sent as a result of Rake failures.

The most likely options you'll want to use are :email_prefix and :exception_recipients. Example:

ExceptionNotifier::Rake.configure(
  :email => {
    :email_prefix => "[Rake Failure] ",
    :exception_recipients => %w{user1@example.com user2@example.com}})

This will prefix the email subjects of Rake failure notifications with [Rake Failure] and will send them to the two given email addresses. Note that if you set the same options when you configure ExceptionNotifier mail notifier itself, they will be overridden but for Rake failures only.

:ignore_if and :ignore_exceptions are also supported. But note that the :ignore_if block will be evaluated for all exceptions, not just the ones triggered by Rake (this is unavoidable because of the design of exception_notification). The first argument to the block passed to :ignore_if is the environment - for all Rake failures and other background exceptions this will be nil, giving you some way to distinguish them.

License

Distributed under an MIT license.