tencentcloud-edgeone-migration-nodejs-v2
Version:
tencentcloud cdn config copy to edgeone
171 lines • 6.41 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.WarmUpTrafficShaping = void 0;
const __1 = require("../..");
const plugins_1 = require("../../plugins");
const utils_1 = require("../../utils");
const kDefaultOptions = {
/**
* 预热时间 (s)
*/
warmTime: 10,
/**
* 预警因子
* 需大于等于 2
*/
warnFactor: 3,
/**
* 空闲回收周期
*/
idlePeriod: 3
};
/**
*
* 预热算法是一个另类的令牌桶算法，此算法实现（描述）了下述函数图像：
*
* ```
* ^ 1/QPS
* |
* 1/coldQPS + /
* | / .
* | / .
* | / .
* | / .
* | / .
* | / .
* | / .
* | / .
* 1/stableQPS +----------/ .
* | . Warm . ← `warmTime` = `warningTokens` 与 `maxTokens` 之间的面积
* | . Time .
* | . .
* 0 +----------+---------+---------------→ currentTokens
* 0 warningTokens maxTokens
* ```
*
* 函数各变量满足如下关系：
* * coldQPS = stableQPS/warnFactor
* * (warningTokens/stableQPS)/(warmTime) = 1/(warnFactor-1)
*/
class WarmUpTrafficShaping {
constructor(options) {
this.type = plugins_1.PluginType.TrafficShaping;
this.name = "warmup";
this.buckets = new WeakMap();
this.disposed = false;
this.options = Object.assign(Object.assign({}, kDefaultOptions), options);
}
// #region dispose
dispose() {
this.disposed = true;
}
get isDisposed() {
return this.disposed;
}
// #endregion
inFlow(rule, partition) {
if (this.disposed) {
return Promise.reject(new __1.StateError("Already disposed"));
}
let bucket = this.buckets.get(rule);
if (typeof bucket === "undefined") {
bucket = this.buildBucket(rule, partition);
this.buckets.set(rule, bucket);
}
if (bucket.partition !== partition) { /** few case */
const { maxTokens, remainingTokens, warningTokens, stableQPS, remainingQPS, coldQPS, slope } = this.buildBucket(rule, partition);
bucket.maxTokens = maxTokens;
bucket.warningTokens = warningTokens;
bucket.stableQPS = stableQPS;
bucket.coldQPS = coldQPS;
bucket.slope = slope;
bucket.remainingTokens = remainingTokens;
bucket.remainingQPS = remainingQPS - bucket.usedQPS;
if (bucket.remainingQPS < 0) {
bucket.remainingQPS = 0;
bucket.usedQPS = remainingQPS;
}
bucket.partition = partition;
}
if (bucket.timer === undefined) {
bucket.timer = setInterval(() => {
if (bucket === undefined) {
(0, utils_1.UNREACHABLE)();
}
if (this.disposed) {
clearInterval(bucket.timer);
bucket.timer = undefined;
return;
}
this.timerTask(bucket);
/**
* 与初始状态相同时，可进入休眠
*/
if (bucket.remainingTokens === bucket.maxTokens) {
bucket.sleepPeriod += 1;
}
else {
bucket.sleepPeriod = 0;
}
if (bucket.sleepPeriod > this.options.idlePeriod) {
clearInterval(bucket.timer);
bucket.timer = undefined;
}
}, 1 * utils_1.kSeconds).unref();
}
if (bucket.remainingQPS >= 1) {
bucket.remainingQPS -= 1;
bucket.usedQPS += 1;
return Promise.resolve();
}
return Promise.reject(new __1.StateError("[plugin] [warmup], quota is limited"));
}
timerTask(bucket) {
const { remainingTokens, warningTokens, stableQPS, coldQPS, usedQPS, slope } = bucket;
if (remainingTokens < warningTokens /** 服务实例处于 "热" 状态 */
|| (remainingTokens > warningTokens && usedQPS < coldQPS) /** 服务实例处于 "冷" 状态，并且当前一秒的 QPS 小于 `coldQPS` */) {
// 增加 stableQPS 个 tokens，但总数不能超过 maxTokens
bucket.remainingTokens += stableQPS;
if (bucket.remainingTokens > bucket.maxTokens) {
bucket.remainingTokens = bucket.maxTokens;
}
}
bucket.remainingTokens -= usedQPS;
bucket.usedQPS = 0;
bucket.remainingQPS = this.calculateQPS(slope, warningTokens, bucket.remainingTokens, stableQPS);
}
calculateQPS(slope, warningTokens, remainingTokens, stableQPS) {
if (remainingTokens <= warningTokens) {
return stableQPS;
}
return stableQPS / (1 + (slope * stableQPS * (remainingTokens - warningTokens)));
}
buildBucket(rule, partition) {
// 取 rules 中最小的 qps 作为 stableQPS
const stableQPS = rule.amounts.reduce((acc, { amount, duration }) => {
const qps = (amount / partition) / (duration / utils_1.kSeconds);
if (qps < acc) {
return qps;
}
return acc;
}, Infinity);
const coldQPS = stableQPS / this.options.warnFactor;
const warningTokens = stableQPS * (this.options.warmTime / (this.options.warnFactor - 1));
const maxTokens = warningTokens + ((2 * this.options.warmTime) / ((1 / stableQPS) + (1 / coldQPS)));
const slope = ((1 / coldQPS) - (1 / stableQPS)) / (maxTokens - warningTokens);
return {
remainingTokens: maxTokens,
warningTokens,
maxTokens,
remainingQPS: this.calculateQPS(slope, warningTokens, maxTokens, stableQPS),
usedQPS: 0,
coldQPS,
stableQPS,
slope,
partition,
sleepPeriod: 0
};
}
}
exports.WarmUpTrafficShaping = WarmUpTrafficShaping;
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