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ActiveJob::Retry Build Status

This is an alpha library in active development, so the API may change.

Automatic retry functionality for ActiveJob. Just include ActiveJob::Retry.new(strategy: :something, **options) in your job class:

class ProcessWebhook < ActiveJob::Base
  queue_as :webhooks

  # Constant delay between attempts:
  include ActiveJob::Retry.new(strategy: :constant,
                               limit: 3,
                               delay: 5.minutes,
                               retryable_exceptions: [TimeoutError, NetworkError])

  # Or, variable delay between attempts:
  include ActiveJob::Retry.new(strategy: :variable,
                               delays: [1.minute, 5.minutes, 10.minutes, 30.minutes])

  # Or, exponential delay between attempts:
  include ActiveJob::Retry.new(strategy: :exponential, limit: 25)

  # You can also use a custom backoff strategy by passing an object which responds to
  # `should_retry?(attempt, exception)`, and `retry_delay(attempt, exception)`
  # to `retry_with`:
  module ChaoticBackoffStrategy
    def self.should_retry?(retry_attempt, exception)
      [true, true, true, true, false].sample
    end

    def self.retry_delay(retry_attempt, exception)
      (0..10).to_a.sample
    end
  end

  include ActiveJob::Retry.new(strategy: ChaoticBackoffStrategy)

  def perform(webhook)
    webhook.process!
  end
end

The retry will get executed before any rescue_from blocks, which will only get executed if the exception is not going to be retried, or has failed the final retry.

constant options

Option Default Description
limit 1 Maximum number of times to attempt the job (default: 1).
unlimited_retries false If set to true, this job will be repeated indefinitely until in succeeds. Use with extreme caution.
delay 0 Time between attempts in seconds (default: 0).
retryable_exceptions nil A whitelist of exceptions to retry. When nil, all exceptions will result in a retry.
fatal_exceptions [] A blacklist of exceptions to not retry (default: []).

exponential options

Option Default Description
limit 1 Maximum number of times to attempt the job (default: 1).
unlimited_retries false If set to true, this job will be repeated indefinitely until in succeeds. Use with extreme caution.
retryable_exceptions nil Same as for constant.
fatal_exceptions [] Same as for constant.

variable options

Option Default Description
delays required An array of delays between attempts in seconds. The first attempt will occur whenever you originally enqueued the job to happen.
min_delay_multiplier If supplied, each delay will be multiplied by a random number between this and max_delay_multiplier.
max_delay_multiplier The other end of the range for min_delay_multiplier. If one is supplied, both must be.
retryable_exceptions nil Same as for constant.
fatal_exceptions [] Same as for constant.

Callback

All strategies support a callback option:

class ProcessWebhook < ActiveJob::Base
  include ActiveJob::Retry.new(
    strategy: :exponential, limit: 25,
    callback: proc do |exception, delay|
      # will be run before each retry
    end
  )
end

callback must be a proc and is run before each retry. It receives the exception and delay before the next retry as arguments. It is evaluated on instance level, so you have access to all instance variables and methods (for example retry_attempt) of your job.

If the callback returns :halt, retry chain is halted and no further retries will be made:

class ProcessWebhook < ActiveJob::Base
  include ActiveJob::Retry.new(
    strategy: :exponential, limit: 25,
    callback: proc do |exception, delay|
      if some_condition
        :halt # this will halt the retry chain
      end
    end
  )
end

Supported backends

Any queue adapter which supports delayed enqueuing (i.e. the enqueue_at method) will work with ActiveJob::Retry, however some queue backends have automatic retry logic, which should be disabled. The cleanest way to do this is to use a rescue_from in the jobs for which you're using ActiveJob::Retry, so the queue backend never perceives the job as having failed. E.g.:

class MyJob < ActiveJob::Base
  include ActiveJob::Retry.new(strategy: :constant,
                               limit: 3,
                               delay: 5,
                               retryable_exceptions: [TimeoutError, NetworkError])

  queue_as :some_job

  rescue_from(StandardError) { |error| MyErrorService.record(error) }

  def perform
    raise "Weird!"
  end
end

Since rescue_froms are only executed once all retries have been attempted, this will send the recurring error to your error service (e.g. Airbrake, Sentry), but will make it appear to the queue backend (e.g. Que, Sidekiq) as if the job has succeeded.

An alternative is to alter the appropriate JobWrapper to alter the configuration of the backend to disable retries globally. For Sidekiq this would be:

# config/initializers/disable_sidekiq_retries.rb
ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper.sidekiq_options(retry: false)

This has the advantages of moving failed jobs to the Dead Job Queue instead of just executing the logic in the rescue_from, which makes manual re-enqueueing easier. On the other hand it does disable Sidekiq's automatic retrying for all ActiveJob jobs.

Supported Versions

Rails 4.2, 5.0, and 5.1 are supported, Ruby 2.1+. Other Ruby runtimes (e.g. JRuby, Rubinius) probably work, but are not tested in Travis CI.

Contributing

Contributions are very welcome! Please open a PR or issue on this repo.