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1e92f2d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | /**
* PRNG-based functions providing enhanced versions of simple delay
* formulas in order to spread out an array of failing operations
* over more uniform time distributions.
*
* Jitter is introduced so that if, for example, twenty requests all
* fail at the same time, that they won't all retry at the same time.
* This should mitigate load on the server after failed requests and
* lead towards more retry attempts succeeding faster than with the
* naïve delay formulas.
* @module state/data-layer/wpcom-http/pipeline/retry-on-failure/delays
*/
import { random } from 'lodash';
/**
* Computes "decorrelated jitter" delay
* @see https://www.awsarchitectureblog.com/2015/03/backoff.html
* @param {number} baseDelay number of ms for initial delay
* @param {number} retryCount attempt number for retry
* @returns {number} ms delay until next attempt
*/
export const decorrelatedJitter = ( baseDelay, retryCount ) => {
const delay = Math.round( ( baseDelay * Math.pow( 2, retryCount - 1 ) ) / 2 );
const jitter = delay + random( 0, delay );
return random( baseDelay, jitter * 3 );
};
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