tencentcloud-edgeone-migration-nodejs-v2
Version:
tencentcloud cdn config copy to edgeone
159 lines • 5.8 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.PolarisDynamicWeight = void 0;
const plugins_1 = require("../../plugins");
const utils_1 = require("../../utils");
const kMaxEstCalls = 2000;
const kDefaultOptions = {
/**
* 成功率倍率
*/
okRatio: 7,
/**
* 延迟倍率
*/
delayRatio: 3
};
const mergeDimensions = (computed) => {
const mergedStat = new Map();
computed.forEach((stat, instance) => {
let errCalls = 0;
let succCalls = 0;
let succDelay = 0;
stat.forEach(({ cost, count }, { success }) => {
if (success) {
succCalls += count;
succDelay += cost;
}
else {
errCalls += count;
}
});
mergedStat.set(instance, { errCalls, succCalls, succDelay });
});
return mergedStat;
};
class PolarisDynamicWeight {
constructor(options) {
this.type = plugins_1.PluginType.WeightAdjuster;
this.name = "PolarisDynamicWeight";
this.previous = Object.create(null);
this.options = Object.assign(Object.assign({}, kDefaultOptions), options);
}
adjust(namespace, service, instances, { statWindow, summaryStat }) {
let minDelay = Infinity;
let maxRate = 0;
let maxWeight = 0;
let sumLoad = 0;
let minWeight = Infinity;
const secondsRatio = statWindow / utils_1.kSeconds;
/**
* 无法计算权重的实例（没有至少一次的成功调用）
*/
const skippedInstances = [];
/**
* 合并后的调用数据（合并未使用维度）
*/
const mergedStat = mergeDimensions(summaryStat);
// #region Round 1
/*
* Round 1:
* 找到服务下各节点的元数据：
* * `minDelay`: 最小延迟
* * `maxRate`: 最大成功率
* * `maxWeight`: 最大静态权重
*/
mergedStat.forEach((stat, instance) => {
const { errCalls, succCalls, succDelay } = stat;
if (!(succCalls > 0)) {
skippedInstances.push(instance);
return;
}
const avgDelay = succDelay / succCalls;
if (avgDelay < minDelay) {
minDelay = avgDelay;
}
const okRate = succCalls / (succCalls + errCalls);
if (okRate > maxRate) {
maxRate = okRate;
}
if (instance.staticWeight > maxWeight) {
maxWeight = instance.staticWeight;
}
});
// #endregion
// #region Round 2
/*
* Round 2:
* 通过各节点的元数据，计算负载值 `load(k)`
*/
const loadInfo = new Map();
mergedStat.forEach((stat, instance) => {
const { errCalls, succCalls, succDelay } = stat;
if (!(succCalls > 0)) {
return;
}
const okRate = succCalls / (succCalls + errCalls);
const delayLoad = ((succDelay / succCalls) / minDelay) || 0 /** NaN ===> 0 */;
const okLoad = maxRate / okRate;
const weightLoad = maxWeight / instance.staticWeight;
const load = ((delayLoad * this.options.delayRatio) + (okLoad * this.options.okRatio)) * weightLoad;
sumLoad += 1 / load;
loadInfo.set(instance, load);
});
// #endregion
// #region Round 3
/*
* Round 3:
* 通过负载值 `load(k)` 与 `estCalls` 计算各节点动态权重，并统计最小权重 `minWeight`
* `estCalls` ∈ [有效节点数, `kMaxEstCalls`]
*/
const latestStat = new WeakMap();
const prevStat = this.previous[`${namespace}.${service}`];
mergedStat.forEach((stat, instance) => {
const { errCalls, succCalls } = stat;
if (!(succCalls > 0)) {
return;
}
let prevCalls;
if (prevStat) {
prevCalls = prevStat.get(instance) || 0;
}
else {
prevCalls = instances.length;
}
const currCalls = succCalls + errCalls;
let nextCalls = (2 * currCalls) - prevCalls; /** est_call_num(t+1) = call_num(t) + (call_num(t)-call_num(t-1)) */
if (nextCalls > kMaxEstCalls) {
nextCalls = kMaxEstCalls;
}
else if (nextCalls < instances.length) {
nextCalls = instances.length;
}
const callsPerSecond = nextCalls / secondsRatio;
let dynamicWeight = Math.floor((callsPerSecond * (1 / loadInfo.get(instance) / sumLoad)) + 0.5);
/**
* 如动态权重计算结果为无穷数，则设置动态权重为最大静态权重
*/
dynamicWeight = Number.isFinite(dynamicWeight) ? dynamicWeight : maxWeight;
instance.dynamicWeight = dynamicWeight;
if (dynamicWeight < minWeight) {
minWeight = dynamicWeight;
}
latestStat.set(instance, currCalls);
});
this.previous[`${namespace}.${service}`] = latestStat;
// #endregion
// #region Round 4
/*
* Round 4:
* 设置 _无法计算权重的实例_ 的动态权重为：`min(min_weight, 实例当前动态权重值)`;
*/
skippedInstances.forEach((instance) => {
instance.dynamicWeight = Math.min(minWeight, instance.dynamicWeight);
});
// #endregion
}
}
exports.PolarisDynamicWeight = PolarisDynamicWeight;
//# sourceMappingURL=polaris.js.map