changedetection/changedetection.js

#!/usr/bin/env node
const CronJob = require('cron').CronJob;
const TimeFormat = require('hh-mm-ss');

// load env variables from file
require('dotenv').config();

const ChangeDetection = require('./scrapers/scraper');

async function run() {
  const cdScraper = new ChangeDetection();
  let startTime = new Date();
  let startTimeStamp = startTime.getTime();
  const delay = process.env.DELAY || 600000;

  console.log('RUN MODE::', process.env.NODE_ENV || 'NOT SET!!');

  if (typeof(process.env.CD_CRON) === 'string' ) {
    console.log(`${cdScraper.id} cron set for ${process.env.CD_CRON}`);
    await cdScraper.run();
    new CronJob(process.env.CD_CRON, async () => {
      console.log('go');
      await cdScraper.run();
      console.log('ready to go again..');
    }, null, true);
  }

  if (typeof(process.env.CD_EVERY) === 'string' ) {
    console.log(`${cdScraper.id}_EVERY set for ${process.env.CD_EVERY} seconds`);

    console.log('++');
    await cdScraper.run();
    console.log('--');
    setInterval(async () => {
      const now = new Date();
      const nowTS = now.getTime();
      const m = parseInt(process.env.CD_EVERY, 10) - (nowTS - startTimeStamp);
      const remains = TimeFormat.fromMs(m, 'hh:mm:ss');

      console.log(`${remains} to go...`);

      if (nowTS - startTimeStamp > process.env.CD_EVERY) {
        await cdScraper.run();
        console.log('ready to go again..');
        startTime = new Date();
        startTimeStamp = startTime.getTime();
      }
    }, delay);
  }

  if (process.env.SCRAPE_START === cdScraper.id) {
    console.log('go');
    await cdScraper.run();
  }

  console.log('Change Detection Launched');
}

process.once('uncaughtException', function caught(err) {
  console.error('Uncaught', err);
});

run();