const express = require('express')
const app = express()
app.get('/', async (req, res) => {
  // 模擬 SSR 會大量的占用內(nèi)存
  const buf = Buffer.alloc(1024 * 1024 * 200, 'a')
  console.log(buf)
  res.end('end')
})
app.get('/another', async (req, res) => {
  res.end('another api')
})
const listener = app.listen(process.env.PORT || 2048, () => {
  console.log('Your app is listening on port ' + listener.address().port)
})

docker run \
-it \
-m 512m \ # 限制容器的內(nèi)存
--rm \
-p 2048:2048 \
--name ssr \
--oom-kill-disable \
ssr

autocannon -c 10 -d 1000 http://localhost:2048

CONTAINER ID   NAME      CPU %     MEM USAGE / LIMIT   MEM %     NET I/O           BLOCK I/O         PIDS
d9c0189e2b56    ssr     0.00%     512MiB / 512MiB     99.99%    14.6kB / 8.65kB   41.9MB / 2.81MB   40

const express = require('express')
const counter = require('./counter.js')
const app = express()
const limit = 2
let cnt = counter()
app.get(
  '/',
  (req, res, next) => {
    cnt(1)
    if (cnt() > limit) {
      res.writeHead(500, {
        'content-type': 'text/pain',
      })
      res.end('exceed limit')
      return
    }
    next()
  },
  async (req, res) => {
    const buf = Buffer.alloc(1024 * 1024 * 200, 'a')
    console.log(buf)
    res.end('end')
  }
)
app.get('/another', async (req, res) => {
  res.end('another api')
})
const listener = app.listen(process.env.PORT || 2048, () => {
  console.log('Your app is listening on port ' + listener.address().port)
})
// counter.js
module.exports = function counter(interval = 1000) {
  let arr = []
  return function cnt(number) {
    const now = Date.now()
    if (number > 0) {
      arr.push({
        time: now,
        value: number,
      })
      const newArr = []
      // 刪除超出一秒的數(shù)據(jù)
      for (let i = 0, len = arr.length; i < len; i++) {
        if (now - arr[i].time > interval) continue
        newArr.push(arr[i])
      }
      arr = newArr
      return
    }
    // 計算前一秒的數(shù)據(jù)和
    let sum = 0
    for (let i = arr.length - 1; i >= 0; i--) {
      const {time, value} = arr[i]
      if (now - time <= interval) {
        sum += value
        continue
      }
      break
    }
    return sum
  }
}

CONTAINER ID   NAME      CPU %     MEM USAGE / LIMIT   MEM %     NET I/O           BLOCK I/O        PIDS
3bd5aa07a3a7   ssr     88.29%    203.1MiB / 512MiB   39.67%    24.5MB / 48.6MB   122MB / 2.81MB   40

curl -m 5  http://localhost:2048
exceed limit

curl -m 5  http://localhost:2048/another
another api

export default class TokenBucket {
  private burst: number
  private rate: number
  private lastFilled: number
  private tokens: number
  constructor(burst: number, rate: number) {
    this.burst = burst
    this.rate = rate
    this.lastFilled = Date.now()
    this.tokens = burst
  }
  setBurst(burst: number) {
    this.burst = burst
    return this
  }
  setRate(rate: number) {
    this.rate = rate
    return this
  }
  take() {
    this.refill()
    if (this.tokens > 0) {
      this.tokens -= 1
      return true
    }
    return false
  }
  refill() {
    const now = Date.now()
    const elapse = now - this.lastFilled
    this.tokens = Math.min(this.burst, this.tokens + elapse * (this.rate / 1000))
    this.lastFilled = now
  }
}

const tokenBucket = new TokenBucket(5, 10)
if (tokenBucket.take()) {
  // Do something
} else {
  // refuse
}

elapse * (this.rate / 1000)

Math.min(this.burst, this.tokens + elapse * (this.rate / 1000))

T = burst / (M - rate) // rate < M