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 this example, Python code is used to enable long polling. The code uses the AWS SDK for Python to enable long polling using these methods of the AWS.SQS client class:

• create_queue
• set_queue_attributes.
• receive_message.

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

All the example code for the Amazon Web Services (AWS) SDK for Python is available here on GitHub.

Prerequisite Tasks

To set up and run this example, you must first complete these tasks:

• Configure your AWS credentials, as described in Quickstart.

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

Get one or more messages (up to 10), from the specified queue. Using the WaitTimeSeconds parameter enables long-poll support. For more information, see Amazon SQS Long Polling in the Amazon SQS Developer Guide.

The example below shows how to:

• Enable a long poll for message on provided 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)