Module: Amigo::SemaphoreBackoffJob::PrependedMethods

Defined in:
lib/amigo/semaphore_backoff_job.rb

Instance Method Summary collapse

Instance Method Details

#perform(*args) ⇒ Object 



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# File 'lib/amigo/semaphore_backoff_job.rb', line 94

def perform(*args)
  self.before_perform(*args) if self.respond_to?(:before_perform)
  return super unless ::Amigo::SemaphoreBackoffJob.enabled?
  key = self.semaphore_key
  size = self.semaphore_size
  # Create a simple counter for the semaphore key.
  # Always increment; also set an expiration if this is the first job.
  # If we need to retry later, make sure we decrement, then schedule for the future.
  # If we run it now, decrement the counter afterwards.
  # If some corruption results in a negative number of jobs in the semaphore,
  # we can delete the key and get back to a default state
  # (this can cause problems but the idea is that
  # we should run at least the configured number of jobs,
  # and eventually the semaphore key will expire/get rebalanced).
  jobs_in_semaphore = Sidekiq.redis do |conn|
    cnt = conn.incr(key)
    conn.expire(key, self.semaphore_expiry) if cnt == 1
    cnt
  end
  if jobs_in_semaphore > size
    Sidekiq.redis { |conn| conn.decr(key) }
    backoff = self.semaphore_backoff
    self.class.perform_in(backoff, *args)
    return
  end
  begin
    super
  ensure
    Sidekiq.redis do |conn|
      new_job_count = conn.decr(key)
      if new_job_count.negative?
        conn.del(key)
        Sidekiq.logger.warn("negative_semaphore_backoff_job_count")
      end
    end
  end
end