Exponential Backoff

exponential-backoff.markdown

Exponential Backoff

A Pen by Craig Palermo on CodePen.

License.

index.jade

div#output

script.babel

/**
* Exponential backoff function that will continue to execute the given
* function until either callback returns true or the max number of
* retries is reached.
*
* Source: http://docs.aws.amazon.com/general/latest/gr/api-retries.html
*
* @params {Number} maxRetries
* @params {Function} callback
* @params {Number} curRetries
*/
const exponentialBackoff = function exponentialBackoff(maxRetries, callback, curRetries = 0) {
  const wait = Math.pow(2, curRetries) * 100;
  const result = callback();
  
  if (curRetries < maxRetries) {
    setTimeout(() => {
      if (result) {
        // Action succeeded
        console.log(`Success after ${curRetries} retries`);
      } else {
        // Action failed, so retry
        console.log(`Trying again in ${wait / 1000} seconds`);
        exponentialBackoff(maxRetries, callback, curRetries + 1);
      }
    }, wait);
  } else {
    // Max number of retries reached, so give up
    console.log(`No longer retrying after ${curRetries} attempts`);
  }
};

// Test
const alwaysFalse = () => false;
exponentialBackoff(10, alwaysFalse);

scripts

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>