How do you implement periodically executing job?

Question

I am recently implementing a system that automatically replies to tweets that contain arbitrary hashtags. This system consists of a process that periodically crawls Twitter and a process that periodically replies to these tweets. Following the tradition of my company, these periodical jobs are implemented with working tables on RDMS that have a status column which would have values like "waiting", "processing" or "succeed". To ensure redundancy, I make multiple same processes running by leveraging low level locks.

My question is, I'm implementing periodically jobs with working tables in RDMS, how these jobs are implemented in generally.

Answer 1

There's a node package cron which allows you to execute code at some specified interval, just like crontab. Here's a link to the package: https://www.npmjs.org/package/cron

For example:

var cronJob = require("cron").CronJob;

// Run this cron job every Sunday (0) at 7:00:00 AM
new cronJob("00 00 7 * * 0", function() {
    // insert code to run here...
}, null, true);

You might be able to use that module to run some job periodically, which crawls twitter or replies to tweets.