Enabling Long Polling in Amazon SQS

This Python example shows you how to enable long polling in Amazon SQS in one of these ways:

• For a newly created queue
• For an existing queue
• Upon receipt of a message

The Scenario

Long polling reduces the number of empty responses by allowing Amazon SQS to wait a specified time for a message to become available in the queue before sending a response. Also, long polling eliminates false empty responses by querying all of the servers instead of a sampling of servers. To enable long polling, you must specify a non-zero wait time for received messages. You can do this by setting the ReceiveMessageWaitTimeSeconds parameter of a queue or by setting the WaitTimeSeconds parameter on a message when it is received.

In these examples, the AWS SDK for Python is used to enable long polling using the following Amazon SQS methods.

• create_queue
• set_queue_attributes.
• receive_message.

For more information, see Amazon SQS Long Polling in the Amazon Simple Queue Service Developer Guide.

Enable Long Polling When Creating a Queue

The example below shows how to:

• Create a queue and enable long polling using create_queue.

Example

import boto3

# Create SQS client
sqs = boto3.client('sqs')

# Create a SQS queue with long polling enabled
response = sqs.create_queue(
    QueueName='SQS_QUEUE_NAME',
    Attributes={'ReceiveMessageWaitTimeSeconds': '20'}
)

print(response['QueueUrl'])

Enable Long Polling on an Existing Queue

The example below shows how to:

• Enable long polling on an existing queue using set_queue_attributes.

Example

import boto3

# Create SQS client
sqs = boto3.client('sqs')

queue_url = 'SQS_QUEUE_URL'

# Enable long polling on an existing SQS queue
sqs.set_queue_attributes(
    QueueUrl=queue_url,
    Attributes={'ReceiveMessageWaitTimeSeconds': '20'}
)

Enable Long Polling on Message Receipt

The example below shows how to:

• Enable long polling for a message on an SQS queue using receive_message.

Example

import boto3

# Create SQS client
sqs = boto3.client('sqs')

queue_url = 'SQS_QUEUE_URL'

# Long poll for message on provided SQS queue
response = sqs.receive_message(
    QueueUrl=queue_url,
    AttributeNames=[
        'SentTimestamp'
    ],
    MaxNumberOfMessages=1,
    MessageAttributeNames=[
        'All'
    ],
    WaitTimeSeconds=20
)

print(response)