Greenjaguar

Applies retry behavior to arbitrary code blocks with different policies like fibonacci, exponential backoff, FixedInterval, etc. This basically is the 'retry' construct on steroids.

Potential uses are for accessing cloud-based services that experience transient faults. We should encapsulate our calls with appropriate retry policies to make our applications more robust.

Features:

• It currently supports following retry policies:
  • Default (no wait)
  • Fibonacci (wait times between retries increase in fibonacci sequence)
  • ExponentialBackOff (wait times increase using exponential backoff)
  • Random (wait times between retries vary between 0 - 5 sec/ms)
  • FixedInterval (wait every 'n' sec/ms)
• You can specify the time unit for retry (:sec or :ms). Default is seconds.
• You can specify the Exception Types for which Retrier should execute. Default is all.
• You can specify that Retrier should fail silently (i.e. it wont raise any error if all retries fail)

If all retries fail, the last exception will be raised.

Add this line to your application's Gemfile:

gem 'greenjaguar'

And then execute:

$ bundle

Or install it yourself as:

$ gem install greenjaguar

class YourClass
  include Greenjaguar

  def your_method
    # Executes your code using the policy
    robust_retry(policy) do
      # Your code goes here
    end
  end

  def policy
    # Build retry policy
    @policy ||= build_policy do
      times 10
      with_strategy :exponential_backoff
      measure_time_in :ms
      only_on_exceptions [Net::HTTPError]
    end
  end
end

In the above example your code block is passed to Greenjaguar which executes it 11 times (first call + 10 retry attempts, in case of failures). If all calls fail, the last exception is raised. Retry happens only if the error raised is of the specified type.

• times: Number of retry attempts
• with_strategy: Retry Strategy to use. Greenjaguar currently supports following
  • exponential_backoff: wait times after each failed retry will increase exponentially. This is the standard used in most of the industry's retry policies.
  • fibonacci: wait times increase in fibonacci series.
  • fixed_interval: wait times between retries are fixed.
  • random: wait times are randomly selected between 0 to 5 secs. Skip this option if you want immediate retries.
• measure_time_in: wait times can be in either sec or ms.
• only_on_exceptions: Provide the Exception Types for which Greenjaguar should retry. Default is all.
• fail_silently: Will fail silently without raising any exceptions after all retries fail.
• never_give_up: Retry will continue indefinitely or until there is success.
• timeout_after: Set a timeout period after which Greenjaguar should quit and just raise the exception.

Refer spec/greenjaguar_spec.rb to se examples of using the options.

1. Need more tests.
2. Need logo.

1. Fork it ( https://github.com/[my-github-username]/greenjaguar/fork )
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 a new Pull Request