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-rw-r--r--node_modules/undici/lib/balanced-pool.js190
1 files changed, 190 insertions, 0 deletions
diff --git a/node_modules/undici/lib/balanced-pool.js b/node_modules/undici/lib/balanced-pool.js
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+++ b/node_modules/undici/lib/balanced-pool.js
@@ -0,0 +1,190 @@
+'use strict'
+
+const {
+ BalancedPoolMissingUpstreamError,
+ InvalidArgumentError
+} = require('./core/errors')
+const {
+ PoolBase,
+ kClients,
+ kNeedDrain,
+ kAddClient,
+ kRemoveClient,
+ kGetDispatcher
+} = require('./pool-base')
+const Pool = require('./pool')
+const { kUrl, kInterceptors } = require('./core/symbols')
+const { parseOrigin } = require('./core/util')
+const kFactory = Symbol('factory')
+
+const kOptions = Symbol('options')
+const kGreatestCommonDivisor = Symbol('kGreatestCommonDivisor')
+const kCurrentWeight = Symbol('kCurrentWeight')
+const kIndex = Symbol('kIndex')
+const kWeight = Symbol('kWeight')
+const kMaxWeightPerServer = Symbol('kMaxWeightPerServer')
+const kErrorPenalty = Symbol('kErrorPenalty')
+
+function getGreatestCommonDivisor (a, b) {
+ if (b === 0) return a
+ return getGreatestCommonDivisor(b, a % b)
+}
+
+function defaultFactory (origin, opts) {
+ return new Pool(origin, opts)
+}
+
+class BalancedPool extends PoolBase {
+ constructor (upstreams = [], { factory = defaultFactory, ...opts } = {}) {
+ super()
+
+ this[kOptions] = opts
+ this[kIndex] = -1
+ this[kCurrentWeight] = 0
+
+ this[kMaxWeightPerServer] = this[kOptions].maxWeightPerServer || 100
+ this[kErrorPenalty] = this[kOptions].errorPenalty || 15
+
+ if (!Array.isArray(upstreams)) {
+ upstreams = [upstreams]
+ }
+
+ if (typeof factory !== 'function') {
+ throw new InvalidArgumentError('factory must be a function.')
+ }
+
+ this[kInterceptors] = opts.interceptors && opts.interceptors.BalancedPool && Array.isArray(opts.interceptors.BalancedPool)
+ ? opts.interceptors.BalancedPool
+ : []
+ this[kFactory] = factory
+
+ for (const upstream of upstreams) {
+ this.addUpstream(upstream)
+ }
+ this._updateBalancedPoolStats()
+ }
+
+ addUpstream (upstream) {
+ const upstreamOrigin = parseOrigin(upstream).origin
+
+ if (this[kClients].find((pool) => (
+ pool[kUrl].origin === upstreamOrigin &&
+ pool.closed !== true &&
+ pool.destroyed !== true
+ ))) {
+ return this
+ }
+ const pool = this[kFactory](upstreamOrigin, Object.assign({}, this[kOptions]))
+
+ this[kAddClient](pool)
+ pool.on('connect', () => {
+ pool[kWeight] = Math.min(this[kMaxWeightPerServer], pool[kWeight] + this[kErrorPenalty])
+ })
+
+ pool.on('connectionError', () => {
+ pool[kWeight] = Math.max(1, pool[kWeight] - this[kErrorPenalty])
+ this._updateBalancedPoolStats()
+ })
+
+ pool.on('disconnect', (...args) => {
+ const err = args[2]
+ if (err && err.code === 'UND_ERR_SOCKET') {
+ // decrease the weight of the pool.
+ pool[kWeight] = Math.max(1, pool[kWeight] - this[kErrorPenalty])
+ this._updateBalancedPoolStats()
+ }
+ })
+
+ for (const client of this[kClients]) {
+ client[kWeight] = this[kMaxWeightPerServer]
+ }
+
+ this._updateBalancedPoolStats()
+
+ return this
+ }
+
+ _updateBalancedPoolStats () {
+ this[kGreatestCommonDivisor] = this[kClients].map(p => p[kWeight]).reduce(getGreatestCommonDivisor, 0)
+ }
+
+ removeUpstream (upstream) {
+ const upstreamOrigin = parseOrigin(upstream).origin
+
+ const pool = this[kClients].find((pool) => (
+ pool[kUrl].origin === upstreamOrigin &&
+ pool.closed !== true &&
+ pool.destroyed !== true
+ ))
+
+ if (pool) {
+ this[kRemoveClient](pool)
+ }
+
+ return this
+ }
+
+ get upstreams () {
+ return this[kClients]
+ .filter(dispatcher => dispatcher.closed !== true && dispatcher.destroyed !== true)
+ .map((p) => p[kUrl].origin)
+ }
+
+ [kGetDispatcher] () {
+ // We validate that pools is greater than 0,
+ // otherwise we would have to wait until an upstream
+ // is added, which might never happen.
+ if (this[kClients].length === 0) {
+ throw new BalancedPoolMissingUpstreamError()
+ }
+
+ const dispatcher = this[kClients].find(dispatcher => (
+ !dispatcher[kNeedDrain] &&
+ dispatcher.closed !== true &&
+ dispatcher.destroyed !== true
+ ))
+
+ if (!dispatcher) {
+ return
+ }
+
+ const allClientsBusy = this[kClients].map(pool => pool[kNeedDrain]).reduce((a, b) => a && b, true)
+
+ if (allClientsBusy) {
+ return
+ }
+
+ let counter = 0
+
+ let maxWeightIndex = this[kClients].findIndex(pool => !pool[kNeedDrain])
+
+ while (counter++ < this[kClients].length) {
+ this[kIndex] = (this[kIndex] + 1) % this[kClients].length
+ const pool = this[kClients][this[kIndex]]
+
+ // find pool index with the largest weight
+ if (pool[kWeight] > this[kClients][maxWeightIndex][kWeight] && !pool[kNeedDrain]) {
+ maxWeightIndex = this[kIndex]
+ }
+
+ // decrease the current weight every `this[kClients].length`.
+ if (this[kIndex] === 0) {
+ // Set the current weight to the next lower weight.
+ this[kCurrentWeight] = this[kCurrentWeight] - this[kGreatestCommonDivisor]
+
+ if (this[kCurrentWeight] <= 0) {
+ this[kCurrentWeight] = this[kMaxWeightPerServer]
+ }
+ }
+ if (pool[kWeight] >= this[kCurrentWeight] && (!pool[kNeedDrain])) {
+ return pool
+ }
+ }
+
+ this[kCurrentWeight] = this[kClients][maxWeightIndex][kWeight]
+ this[kIndex] = maxWeightIndex
+ return this[kClients][maxWeightIndex]
+ }
+}
+
+module.exports = BalancedPool