Deferred Exception

Have you ever found yourself writing code like this? Have you presumed that you would notice a problem and go looking in your logs to find the problem?

class EmailBlaster
  def self.process_all!
    all.each { |email| email.blast! }
  end

  def blast!
    begin
      # do some atomic work here
    rescue StandardError => e
      Logger.debug("Something went wrong #{e.message}")
    end
  end

  # &c.
end

Wouldn't it be nice, nay preferable, to accrue exceptions without stopping the subsequent atomic operations?

Add this line to your application's Gemfile:

gem 'deferred_exception'

And then execute:

$ bundle

Or install it yourself as:

$ gem install deferred_exception

Deferred Exception adds a defer_exceptions method to the Enumerable module that wraps the enumberable object and stores any exceptions that are raised during iteration.

class EmailBlaster
  def self.process_all!
    all.defer_exceptions.each do { |email| email.blast! }
  end

  def blast!
    # important, atomic work here
  end
end

Any exceptions will be caught and queued into a ExceptionSet class, a subclass of StandardError and will be raised once the iteration is complete. ExceptionSet#message will be a string containing messages and backtraces from all caught exceptions

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request