One approach to exponential backoff in Ruby

exponential_backoff.rb

##
# Call +fn+ up to +retries+ times or until it does not raise a StandardError,
# returning its result. While exceptions are raised, wait an increasing interval
# between attempts. The interval will increase as k^N.
#
# Examples
# myfun = lambda { raise "failed" }
# backoff(myfun) # calls myfun at time = 0, 1, 4, 11, 26, 57s
# backoff(myfun, retries: 2, k: 1) # calls at time 0, 1, 3, 6, 10, 15s

def backoff(fn, retries: 5, delay: 0, k: 2)
  sleep(delay)
  fn.call
rescue => e
  if retries > 0
    backoff(fn, retries: retries - 1, delay: delay * k + 1, k: k)
  else
    raise e
  end
end

mock_network_call = -> { puts Time.now.to_i; raise "hi" }
backoff(mock_network_call)