Overleaf/libraries/metrics/open_sockets.js

/*
 * decaffeinate suggestions:
 * DS102: Remove unnecessary code created because of implicit returns
 * DS205: Consider reworking code to avoid use of IIFEs
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
let OpenSocketsMonitor
const { URL } = require('url')
const seconds = 1000

// In Node 0.10 the default is 5, which means only 5 open connections at one.
// Node 0.12 has a default of Infinity. Make sure we have no limit set,
// regardless of Node version.
require('http').globalAgent.maxSockets = Infinity
require('https').globalAgent.maxSockets = Infinity

module.exports = OpenSocketsMonitor = {
  monitor(logger) {
    const interval = setInterval(
      () => OpenSocketsMonitor.gaugeOpenSockets(),
      5 * seconds
    )
    const Metrics = require('./index')
    return Metrics.registerDestructor(() => clearInterval(interval))
  },

  gaugeOpenSockets() {
    let agents, hostname, url
    const Metrics = require('./index')
    const object = require('http').globalAgent.sockets
    for (url in object) {
      agents = object[url]
      url = new URL(`http://${url}`)
      hostname =
        url.hostname != null ? url.hostname.replace(/\./g, '_') : undefined
      Metrics.gauge(`open_connections.http.${hostname}`, agents.length)
    }
    return (() => {
      const result = []
      const object1 = require('https').globalAgent.sockets
      for (url in object1) {
        agents = object1[url]
        url = new URL(`https://${url}`)
        hostname =
          url.hostname != null ? url.hostname.replace(/\./g, '_') : undefined
        result.push(
          Metrics.gauge(`open_connections.https.${hostname}`, agents.length)
        )
      }
      return result
    })()
  }
}