Task Scheduling Service

Description

The Task Scheduling Service efficiently manages a Job queue, enabling the scheduling of events that trigger specific actions like invoking functions or calling webhooks. It utilizes a sorted set in Redis to implement the Job queue. This service finds widespread application in our applications, allowing us to schedule various tasks that are required to be executed at a certain date/time.

• It uses a Sorted set in Redis for implementing the Job queue.
• Runs a cron job every 10 seconds and triggers all events that should have been triggered.
• Creating new event triggers via webhook.

How It Works

How events are triggered ?

For the Job Queue, We use a Sorted Set which keeps a list of strings sorted based on the respective numerical score. We use a string < Event Type > + < Event Id> for value and the date/time in seconds for score.

Value < Type >_< Id >	Score < Date & Time in ISO String >
eventA_123456	1644216228
eventC_123456	1644219428
eventA_143234	1644259428
eventB_143234	1644259728

Every 10 seconds, All events with score less than current time are fetched and are triggered and then removed from queue.

What Action to perform ?

In the triggerEvent Function, One can customize the actions to be performed for a specific event using the switch case in the function. Here we perform different API calls with different payload for different event types.

API Reference

Create Event

  POST /scheduler/create-event

Parameter	Type	Description
scheduledDate	string	Required. Date and Time when the event should be triggered in ISO string format
type	string	Required. Type represents event type - should not contain "_" underscores
id	string	Required. Type represents event type - should not contain "_" underscores

Environment variables

Name	Description
SCHEDULER_MSC_PORT	Port to Scheduler Service
BASE_URL	Base URL to your API or Web Server
REDIS_URL	Connection URL to your Redis DB

Installation

1. cd task-scheduling-service-redis
2. To run project in dev/watch mode run npm run start:dev.
3. Build the application using npm run build.
4. To run project in production mode run npm run start:prod.

Author

• @Nayan-Shrivastava