sqs-consumer

What is sqs-consumer?

The sqs-consumer npm package is a simple to use library for building Amazon Simple Queue Service (SQS) based applications. It allows you to create consumers that process messages from SQS queues with ease, handling message polling, error handling, and visibility timeout extensions.

What are sqs-consumer's main functionalities?

Creating a Consumer

This code sample demonstrates how to create a basic consumer that reads messages from an SQS queue and logs the message body to the console.

const { Consumer } = require('sqs-consumer');
const AWS = require('aws-sdk');

const app = Consumer.create({
  queueUrl: 'https://sqs.us-east-1.amazonaws.com/account-id/queue-name',
  handleMessage: async (message) => {
    console.log(message.Body);
  },
  sqs: new AWS.SQS()
});

app.on('error', (err) => {
  console.error(err.message);
});

app.start();

Error Handling

This code sample shows how to handle errors that occur during message processing. The 'error' event is emitted for general errors, while the 'processing_error' event is specifically for errors that occur during message handling.

const { Consumer } = require('sqs-consumer');
const AWS = require('aws-sdk');

const app = Consumer.create({
  queueUrl: 'https://sqs.us-east-1.amazonaws.com/account-id/queue-name',
  handleMessage: async (message) => {
    throw new Error('Processing error');
  },
  sqs: new AWS.SQS()
});

app.on('error', (err) => {
  console.error('Error occurred:', err.message);
});

app.on('processing_error', (err) => {
  console.error('Processing error:', err.message);
});

app.start();

Batch Processing

This code sample demonstrates how to process messages in batches. The 'handleMessageBatch' function receives an array of messages, allowing for more efficient processing.

const { Consumer } = require('sqs-consumer');
const AWS = require('aws-sdk');

const app = Consumer.create({
  queueUrl: 'https://sqs.us-east-1.amazonaws.com/account-id/queue-name',
  handleMessageBatch: async (messages) => {
    messages.forEach(message => console.log(message.Body));
  },
  sqs: new AWS.SQS()
});

app.on('error', (err) => {
  console.error(err.message);
});

app.start();

Other packages similar to sqs-consumer

aws-sdk

The aws-sdk package is the official AWS SDK for JavaScript, which includes support for SQS. It provides a more comprehensive set of tools for interacting with AWS services, including SQS. However, it requires more boilerplate code to achieve the same functionality as sqs-consumer.

sqs-producer

The sqs-producer package is designed for sending messages to SQS queues, complementing the sqs-consumer package. While sqs-consumer focuses on consuming messages, sqs-producer is used for producing messages, making them a good pair for full SQS queue management.

node-sqs

The node-sqs package is another library for interacting with SQS. It provides both producing and consuming capabilities but is less specialized and streamlined compared to sqs-consumer, which is focused solely on consuming messages.

README

sqs-consumer

Build SQS-based applications without the boilerplate. Just define an async function that handles the SQS message processing.

Installation

To install this package, simply enter the following command into your terminal (or the variant of whatever package manager you are using):

npm install --save-dev sqs-consumer

Note This library assumes you are using AWS SDK v3. If you are using v2, please install v5.8.0:

npm install sqs-consumer@5.8.0 --save-dev

Usage

import { Consumer } from 'sqs-consumer';

const app = Consumer.create({
  queueUrl: 'https://sqs.eu-west-1.amazonaws.com/account-id/queue-name',
  handleMessage: async (message) => {
    // do some work with `message`
  }
});

app.on('error', (err) => {
  console.error(err.message);
});

app.on('processing_error', (err) => {
  console.error(err.message);
});

app.start();

• The queue is polled continuously for messages using long polling.
• Messages are deleted from the queue once the handler function has completed successfully.
• Throwing an error (or returning a rejected promise) from the handler function will cause the message to be left on the queue. An SQS redrive policy can be used to move messages that cannot be processed to a dead letter queue.
• By default messages are processed one at a time – a new message won't be received until the first one has been processed. To process messages in parallel, use the batchSize option detailed below.

You can also find some examples of sqs-consumer implemented in various ways within the examples directory.

Credentials

By default the consumer will look for AWS credentials in the places specified by the AWS SDK. The simplest option is to export your credentials as environment variables:

export AWS_SECRET_ACCESS_KEY=...
export AWS_ACCESS_KEY_ID=...

If you need to specify your credentials manually, you can use a pre-configured instance of the SQS Client client.

import { Consumer } from 'sqs-consumer';
import { SQSClient } from '@aws-sdk/client-sqs';

const app = Consumer.create({
  queueUrl: 'https://sqs.eu-west-1.amazonaws.com/account-id/queue-name',
  handleMessage: async (message) => {
    // ...
  },
  sqs: new SQSClient({
    region: 'my-region',
    credentials: {
      accessKeyId: 'yourAccessKey',
      secretAccessKey: 'yourSecret'
    }
  })
});

app.on('error', (err) => {
  console.error(err.message);
});

app.on('processing_error', (err) => {
  console.error(err.message);
});

app.on('timeout_error', (err) => {
  console.error(err.message);
});

app.start();

AWS IAM Permissions

Consumer will receive and delete messages from the SQS queue. Ensure sqs:ReceiveMessage, sqs:DeleteMessage, sqs:DeleteMessageBatch, sqs:ChangeMessageVisibility and sqs:ChangeMessageVisibilityBatch access is granted on the queue being consumed.

API

Consumer.create(options)

Creates a new SQS consumer using the defined options.

consumer.start()

Start polling the queue for messages.

consumer.stop()

Stop polling the queue for messages (pre existing requests will still be made until concluded).

consumer.isRunning

Returns the current polling state of the consumer: true if it is actively polling, false if it is not.

Events

Each consumer is an EventEmitter and emits these events.

Contributing

We welcome and appreciate contributions for anyone who would like to take the time to fix a bug or implement a new feature.

But before you get started, please read the contributing guidelines and code of conduct.

License

SQS Consumer is distributed under the Apache License, Version 2.0, see LICENSE for more information.