tencentcloud-edgeone-migration-nodejs-v2
Version:
tencentcloud cdn config copy to edgeone
124 lines • 4.09 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.UnirateTrafficShaping = void 0;
const __1 = require("../..");
const plugins_1 = require("../../plugins");
const kDefaultOptions = {
/**
* 最长等待时间 (ms)
*/
maxWaitingTime: Infinity,
/**
* 空闲回收周期
*/
idlePeriod: 3
};
/**
* Leaky bucket
* (https://en.wikipedia.org/wiki/Leaky_bucket)
*/
class UnirateTrafficShaping {
constructor(options) {
this.type = plugins_1.PluginType.TrafficShaping;
this.name = "unirate";
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) {
const { capacity, interval, rate } = this.buildBucket(rule, partition);
bucket.capacity = capacity;
bucket.interval = interval;
bucket.rate = rate;
bucket.partition = partition;
if (bucket.timer !== undefined) {
clearInterval(bucket.timer);
bucket.timer = undefined;
}
}
if (bucket.queue.length === bucket.capacity) {
return Promise.reject(new __1.StateError(`[plugin] [unirate], timeout(${this.options.maxWaitingTime}ms)`));
}
const quota = new Promise((...args) => {
bucket.queue.push(args);
});
if (bucket.timer === undefined) {
this.allocate(bucket);
bucket.timer = setInterval(() => {
if (this.disposed) {
bucket.queue.forEach(([, reject]) => process.nextTick(reject, new __1.StateError("Already disposed")));
bucket.queue = [];
clearInterval(bucket.timer);
bucket.timer = undefined;
bucket.sleepPeriod = 0;
return;
}
if (!this.allocate(bucket)) {
bucket.sleepPeriod += 1;
}
else {
bucket.sleepPeriod = 0;
}
if (bucket.sleepPeriod > this.options.idlePeriod) {
clearInterval(bucket.timer);
bucket.timer = undefined;
}
}, bucket.interval).unref();
}
return quota;
}
allocate(bucket) {
const { queue, rate } = bucket;
const hasRequest = queue.length > 0;
/*
* note:
* 这里在下一个 tick 内调用 `resolve`，以避免用户代码异常造成流程中断
*/
queue.splice(0, rate).forEach(([reslove]) => process.nextTick(reslove));
return hasRequest;
}
buildBucket(rule, partition) {
let interval = rule.amounts.reduce((acc, { amount, duration }) => {
const rate = duration / (amount / partition);
if (rate > acc) {
return rate;
}
return acc;
}, 0);
let rate = 1;
if (interval < 1) {
rate = ~~(1 / interval);
interval = 1;
}
else {
interval = Math.floor(interval);
}
return {
queue: [],
interval,
rate,
capacity: Math.floor(rate * Math.floor(this.options.maxWaitingTime / interval)),
sleepPeriod: 0,
partition
};
}
}
exports.UnirateTrafficShaping = UnirateTrafficShaping;
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