// @flow
// Copyright (c) 2016 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
import * as constants from '../constants.js';
export default class ProbabilisticSampler {
_samplingRate: number;
constructor(samplingRate: number) {
if (samplingRate < 0.0 || samplingRate > 1.0) {
throw new Error(`The sampling rate must be less than 0.0 and greater than 1.0. Received ${samplingRate}`);
}
this._samplingRate = samplingRate;
}
name(): string {
return 'ProbabilisticSampler';
}
get samplingRate(): number {
return this._samplingRate;
}
isSampled(operation: string, tags: any): boolean {
let decision = this.random() < this._samplingRate;
if (decision) {
tags[constants.SAMPLER_TYPE_TAG_KEY] = constants.SAMPLER_TYPE_PROBABILISTIC;
tags[constants.SAMPLER_PARAM_TAG_KEY] = this._samplingRate;
}
return decision;
}
random(): number {
return Math.random();
}
equal(other: Sampler): boolean {
if (!(other instanceof ProbabilisticSampler)) {
return false;
}
return this.samplingRate === other.samplingRate;
}
close(callback: Function): void {
if (callback) {
callback();
}
}
}
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