Build SQS-based Node applications without the boilerplate
npm install @vercel/sqs-consumer
Build SQS-based applications without the boilerplate. Just define an async function that handles the SQS message processing.
``bash`
npm install sqs-consumer --save
`js
const { Consumer } = require('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.keepAlive: true
* By default, the default Node.js HTTP/HTTPS SQS agent creates a new TCP connection for every new request (AWS SQS documentation). To avoid the cost of establishing a new connection, you can reuse an existing connection by passing a new SQS instance with .`js
const { Consumer } = require('sqs-consumer');
const AWS = require('aws-sdk');
const app = Consumer.create({
queueUrl: 'https://sqs.eu-west-1.amazonaws.com/account-id/queue-name',
handleMessage: async (message) => {
// do some work with message
},
sqs: new AWS.SQS({
httpOptions: {
agent: new https.Agent({
keepAlive: true
})
}
})
});
app.on('error', (err) => {
console.error(err.message);
});
app.on('processing_error', (err) => {
console.error(err.message);
});
app.start();
`
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:
`bash`
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 AWS SQS client:
`js
const { Consumer } = require('sqs-consumer');
const AWS = require('aws-sdk');
AWS.config.update({
region: 'eu-west-1',
accessKeyId: '...',
secretAccessKey: '...'
});
const app = Consumer.create({
queueUrl: 'https://sqs.eu-west-1.amazonaws.com/account-id/queue-name',
handleMessage: async (message) => {
// ...
},
sqs: new AWS.SQS()
});
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();
`
Creates a new SQS consumer.
#### Options
* queueUrl - _String_ - The SQS queue URLregion
* - _String_ - The AWS region (default eu-west-1)handleMessage
* - _Function_ - An async function (or function that returns a Promise) to be called whenever a message is received. Receives an SQS message object as it's first argument.handleMessageBatch
* - _Function_ - An async function (or function that returns a Promise) to be called whenever a batch of messages is received. Similar to handleMessage but will receive the list of messages, not each message individually. If both are set, handleMessageBatch overrides handleMessage.handleMessageTimeout
* - _Number_ - Time in ms to wait for handleMessage to process a message before timing out. Emits timeout_error on timeout. By default, if handleMessage times out, the unprocessed message returns to the end of the queue.attributeNames
* - _Array_ - List of queue attributes to retrieve (i.e. ['All', 'ApproximateFirstReceiveTimestamp', 'ApproximateReceiveCount']).messageAttributeNames
* - _Array_ - List of message attributes to retrieve (i.e. ['name', 'address']).batchSize
* - _Number_ - The number of messages to request from SQS when polling (default 1). This cannot be higher than the AWS limit of 10.visibilityTimeout
* - _Number_ - The duration (in seconds) that the received messages are hidden from subsequent retrieve requests after being retrieved by a ReceiveMessage request.heartbeatInterval
* - _Number_ - The interval (in seconds) between requests to extend the message visibility timeout. On each heartbeat the visibility is extended by adding visibilityTimeout to the number of seconds since the start of the handler function. This value must less than visibilityTimeout.terminateVisibilityTimeout
* - _Boolean_ or _Function_ - If a _Boolean_ and true, sets the message visibility timeout to 0 after a processing_error (defaults to false). If a _Function_, the function receives the SQS message as its first argument, and should return the visibility timeout to apply for the message.waitTimeSeconds
* - _Number_ - The duration (in seconds) for which the call will wait for a message to arrive in the queue before returning.authenticationErrorTimeout
* - _Number_ - The duration (in milliseconds) to wait before retrying after an authentication error (defaults to 10000).pollingWaitTimeMs
* - _Number_ - The duration (in milliseconds) to wait before repolling the queue (defaults to 0).sqs
* - _Object_ - An optional AWS SQS object to use if you need to configure the client manually
Start polling the queue for messages.
Stop polling the queue for messages.
Returns the current polling state of the consumer: true if it is actively polling, false if it is not.
Each consumer is an EventEmitter and emits the following events:
|Event|Params|Description|
|-----|------|-----------|
|error|err, [message]|Fired when an error occurs interacting with the queue. If the error correlates to a message, that error is included in Params|processing_error
||err, message|Fired when an error occurs processing the message.|timeout_error
||err, message|Fired when handleMessageTimeout is supplied as an option and if handleMessage times out.|message_received
||message|Fired when a message is received.|message_processed
||message|Fired when a message is successfully processed and removed from the queue.|response_processed
||None|Fired after one batch of items (up to batchSize) has been successfully processed.|stopped
||None|Fired when the consumer finally stops its work.|empty
||None|Fired when the queue is empty (All messages have been consumed).|
Consumer will receive and delete messages from the SQS queue. Ensure sqs:ReceiveMessage and sqs:DeleteMessage` access is granted on the queue being consumed.