86 lines
1.4 KiB
JavaScript
86 lines
1.4 KiB
JavaScript
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/**
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* Expose `Backoff`.
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*/
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module.exports = Backoff;
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/**
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* Initialize backoff timer with `opts`.
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*
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* - `min` initial timeout in milliseconds [100]
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* - `max` max timeout [10000]
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* - `jitter` [0]
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* - `factor` [2]
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*
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* @param {Object} opts
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* @api public
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*/
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function Backoff(opts) {
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opts = opts || {};
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this.ms = opts.min || 100;
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this.max = opts.max || 10000;
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this.factor = opts.factor || 2;
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this.jitter = opts.jitter > 0 && opts.jitter <= 1 ? opts.jitter : 0;
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this.attempts = 0;
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}
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/**
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* Return the backoff duration.
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*
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* @return {Number}
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* @api public
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*/
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Backoff.prototype.duration = function(){
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var ms = this.ms * Math.pow(this.factor, this.attempts++);
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if (this.jitter) {
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var rand = Math.random();
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var deviation = Math.floor(rand * this.jitter * ms);
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ms = (Math.floor(rand * 10) & 1) == 0 ? ms - deviation : ms + deviation;
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}
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return Math.min(ms, this.max) | 0;
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};
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/**
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* Reset the number of attempts.
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*
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* @api public
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*/
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Backoff.prototype.reset = function(){
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this.attempts = 0;
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};
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/**
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* Set the minimum duration
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*
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* @api public
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*/
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Backoff.prototype.setMin = function(min){
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this.ms = min;
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};
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/**
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* Set the maximum duration
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*
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* @api public
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*/
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Backoff.prototype.setMax = function(max){
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this.max = max;
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};
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/**
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* Set the jitter
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*
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* @api public
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*/
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Backoff.prototype.setJitter = function(jitter){
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this.jitter = jitter;
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};
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