sqs-listener.md

SQSlisteners

This is the class you should extend to code your own Listeners. You can customize them with the following methods and getters:

Methods

async process()

This method is REQUIRED, and should have the logic of your Listener.

async validate()

This method validates the struct returned in the struct() getter. You can extend to perform custom validations. Remember to always call await super.validate() first.

Getters

• struct (getter) Returns a validation struct (see @janiscommerce/superstruct)
• event (getter) Returns the event of the message.
• attributes (getter) Returns the attributes of the message.

SQSServerlessHandler

This is the class you should use as a handler for your AWS Lambda functions.

async handle(Listener, event, context, callback)

This will handle the lambda execution.

• Listener {Class} The event listener class. It's recommended to extend from this package SQSListener class.
• event {object} The lambda event object
• context {object} The lambda context object
• callback {function} The lambda callback function

ServerlessHandlerError

Handled errors of the SQS Event or runtime errors inside process. If the error was emitted on the process method you might find more information about the error source in the previousError property.

It also uses the following error codes:

Name	Value	Description
INVALID_EVENT	1	The SQS event is empty or invalid
INVALID_RECORDS	2	The Records of the event are empty or invalid
INVALID_MESSAGE	3	The SQS Message of the Records are empty or invalid
PROCESS_NOT_FOUND	4	The process method is not implemented in the event listener class
INTERNAL_ERROR	5	Errors generated in the event listener class process method

Examples

SQS Listener

'use strict';

const logger = require('lllog')();

const {
	SQSListener,
	SQSServerlessHandler
} = require('@janiscommerce/aws-listeners');

class MySQSEventListener extends SQSListener {

	get struct() {
		return {
			id: 'objectId',
			message: 'string'
		};
	}

	async process() {
		const { id, message } = this.event;
		logger.info(`Received a message for ID ${id}: ${message}`);
	}

}

module.exports.handler = (...args) => SQSServerlessHandler.handle(MySQSEventListener, ...args);