Canary.js - Chirp til you drop

canary.js

const { readFile, appendFile } = require("fs")

let logfile = "canary.log"

const now = () => new Date().toISOString()

const sleep = ms => new Promise(resolve => setTimeout(resolve, ms))

const appendFileP = (filename, data) =>
  new Promise((resolve, reject) => {
    appendFile(filename, `\n${data}`, err => {
      if (err) reject(err)
      else resolve()
    })
  })

const addToLog = async log => {
  const notification = log !== undefined ? log : now()
  console.log(notification)
  await appendFileP(logfile, notification)
}

const loop = async () => {
  while (true) {
    await sleep(10000)
    addToLog()
  }
}

;(() => {
  logfile = process.argv[2] || logfile
  console.log(`> writing to ${logfile}`)

  addToLog(`Started shutdown canary at ${now()}`)
  try {
    loop()
  } catch (err) {
    console.error(err)
  }
})()