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 sqs-consumer

If you would like to use JSR instead, you can find the package here.

Node version

We will only support Node versions that are actively or security supported by the Node team. You can find the list of versions that are actively supported here.

Documentation

Visit https://bbc.github.io/sqs-consumer/ for the full API documentation.

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.
• 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 here.
  • It's also important to await any processing that you are doing to ensure that messages are processed one at a time.
• By default, messages that are sent to the handleMessage and handleMessageBatch functions will be considered as processed if they return without an error.
  • To acknowledge individual messages, please return the message that you want to acknowledge if you are using handleMessage or the messages for handleMessageBatch.
    • To note, returning an empty object or an empty array will be considered an acknowledgement of no message(s) and will result in no messages being deleted. If you would like to change this behaviour, please use the alwaysAcknowledge option detailed here.
    • By default, if an object or an array is not returned, all messages will be acknowledged.
• Messages are deleted from the queue once the handler function has completed successfully (the above items should also be taken into account).

FIFO Queue Support

When using SQS Consumer with FIFO (First-In-First-Out) queues, you might see a warning message in your logs.

As mentioned in the warning, we do not explicitly test SQS Consumer with FIFO queues, this means that we cannot guarantee that the library will work as expected, however, with the correct configuration, it should. If you have done that and believe FIFO to be working as expected, you can suppress the warning by setting suppressFifoWarning: true.

To note: In order to maintain FIFO ordering, you should always use the handleMessageBatch method instead of handleMessage.

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(options)

Stop polling the queue for messages. You can find the options definition here.

By default, the value of abort is set to false which means pre existing requests to AWS SQS will still be made until they have concluded. If you would like to abort these requests instead, pass the abort value as true, like so:

consumer.stop({ abort: true })

consumer.status

Returns the current status of the consumer.

• isRunning - true if the consumer has been started and not stopped, false if was not started or if it was stopped.
• isPolling - true if the consumer is actively polling, false if it is not.

Note: This method is not available in versions before v9.0.0 and replaced the method isRunning to supply both running and polling states.

consumer.updateOption(option, value)

Updates the provided option with the provided value.

Please note that any update of the option pollingWaitTimeMs will take effect only on next polling cycle.

You can find out more about this here.

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.