retry.js

/*
 * Copyright 2012-2016 the original author or authors
 * @license MIT, see LICENSE.txt for details
 *
 * @author Jeremy Grelle
 * @author Scott Andrews
 */

'use strict';

var interceptor, delay;

interceptor = require('../interceptor');
delay = require('../util/delay');

/**
 * Retries a rejected request using an exponential backoff.
 *
 * Defaults to an initial interval of 100ms, a multiplier of 2, and no max interval.
 *
 * @param {Client} [client] client to wrap
 * @param {number} [config.intial=100] initial interval in ms
 * @param {number} [config.multiplier=2] interval multiplier
 * @param {number} [config.max] max interval in ms
 *
 * @returns {Client}
 */
module.exports = interceptor({
	init: function (config) {
		config.initial = config.initial || 100;
		config.multiplier = config.multiplier || 2;
		config.max = config.max || Infinity;
		return config;
	},
	error: function (response, config, meta) {
		var request;

		request = response.request;
		request.retry = request.retry || config.initial;

		return delay(request.retry, request).then(function (request) {
			if (request.canceled) {
				// cancel here in case client doesn't check canceled flag
				return Promise.reject({ request: request, error: 'precanceled' });
			}
			request.retry = Math.min(request.retry * config.multiplier, config.max);
			return meta.client(request);
		});
	}
});