Setting a timer in Node.js

Question

I need to run code in Node.js every 24 hours. I came across a function called setTimeout. Below is my code snippet

var et = require('elementtree');
var XML = et.XML;
var ElementTree = et.ElementTree;
var element = et.Element;
var subElement = et.SubElement;
var data='<?xml version="1.0"?><entries><entry><TenantId>12345</TenantId><ServiceName>MaaS</ServiceName><ResourceID>enAAAA</ResourceID><UsageID>550e8400-e29b-41d4-a716-446655440000</UsageID><EventType>create</EventType><category term="monitoring.entity.create"/><DataCenter>global</DataCenter><Region>global</Region><StartTime>Sun Apr 29 2012 16:37:32 GMT-0700 (PDT)</StartTime><ResourceName>entity</ResourceName></entry><entry><TenantId>44445</TenantId><ServiceName>MaaS</ServiceName><ResourceID>enAAAA</ResourceID><UsageID>550e8400-e29b-41d4-a716-fffffffff000</UsageID><EventType>update</EventType><category term="monitoring.entity.update"/><DataCenter>global</DataCenter><Region>global</Region><StartTime>Sun Apr 29 2012 16:40:32 GMT-0700 (PDT)</StartTime><ResourceName>entity</ResourceName></entry></entries>'
etree = et.parse(data);
var t = process.hrtime();
// [ 1800216, 927643717 ]

setTimeout(function () {
  t = process.hrtime(t);
  // [ 1, 6962306 ]
  console.log(etree.findall('./entry/TenantId').length); // 2
  console.log('benchmark took %d seconds and %d nanoseconds', t[0], t[1]);
  //benchmark took 1 seconds and 6962306 nanoseconds
},1000);

I want to run the above code once per hour and parse the data. For my reference I had used one second as the timer value. Any idea how to proceed will be much helpful.

Answer 1

There are basically three ways to go

1. setInterval()

The setTimeout(f, n) function waits n milliseconds and calls function f. The setInterval(f, n) function calls f every n milliseconds.

setInterval(function(){
  console.log('test');
}, 60 * 60 * 1000);      

This prints test every hour. You could just throw your code (except the require statements) into a setInterval(). However, that seems kind of ugly to me. I'd rather go with:

2. Scheduled Tasks Most operating systems have a way of sheduling tasks. On Windows this is called "Scheduled Tasks" on Linux look for cron.

3. Use a libary As I realized while answering, one could even see this as a duplicate of that question.