background-process-js

A set of util tools for create background process.

How to use?

You have two manners for use background-process-js, you can use some our implementations or you can create your own.

$3

``ts
import { SQSClient } from 'aws-sdk';
import { SQSConsumer, SQSConfig, ConsumerConfig } from 'background-process-js';

const sqs = new SQSClient();
const sqsConfig = {
client: sqs,
WaitTimeSeconds: 20,
VisibilityTimeout: 30,
MaxNumberOfMessages: 10,
mainQueueUrl: 'https://sqs.{region}.amazonaws.com/{accountID}/{queueName}'
deadQueueUrl: 'https://sqs.{region}.amazonaws.com/{accountID}/{queueName}'
};


// If it is true will continuously polling in the queue,
// and if the queue return less than MaxNumberOfMessages and greather than zero
// will set a timeout with WaitTimeSeconds number for continuously polling queue.

// If it is false you must control the timeouts and times for polling.
const continuouslyPolling = true || false;
// Default false
const consumer = new SQSConsumer(sqsConfig, continuouslyPolling);
`

$3

`ts
import { Message } from 'aws-sdk';
import { Consumer } from "background-process-js";

export class SQSConsumer extends Consumer {

constructor() {
super({
hasDeadQueue: true || false,
maxReceivedMessages: 10,
continuouslyPolling: true || false,
timeoutAfterEndingPollingInMilliseconds: 20 * 1000, // 20 seconds
});
}

protected async getMessages(): Promise {
// code...
}

protected async deleteMessages(messages: Message[]): Promise {
// code...
}

protected async markAsDeadMessages(messages: Message[]): Promise {
// code...
}
}
`

For any implementation you can set the following listeners and methods.
`ts
// This process event will be execute by default every 1 minute
consumer.process(({ messages, scalingId }) => {
// code for processing message...

const deadMessages = [...messages];
const processedMessages = [...messages];

if (isInvalidMessage) {
// This emitter will be log an error and stop consumer
consumer.catch(new Error());
}

// This emmiter will be delete message from queue
consumer.finish(scalingId, processedMessages);

// This emmiter will be send messages to dead queue
consumer.dead(scalingId, deadMessages);
});

// This method will start many pollings
consumer.poll(5);
``