CODEWITHSUNDEEP
pythonamazon-web-servicesboto3amazon-sqs
Johnny John Boy
Johnny John Boy

Reputation: 3202

Why do my AWS SQS messages not get deleted?

I have an AWS SQS queue which receives the messages, iterates through them printing the details and then I attempt to delete them. Unfortunately they are not deleting even though I get a success response. I can't figure out why they are not being removed when I am sure I've used similar code before.

The basic example I'm trying is like this:

import boto3

# Create SQS client
sqs = boto3.client('sqs',
                    region_name='',
                    aws_access_key_id='',
                    aws_secret_access_key=''
                    )

queue_url = ''

# Receive message from SQS queue
response = sqs.receive_message(
    QueueUrl=queue_url,
    AttributeNames=[
        'All'
    ],
    MaxNumberOfMessages=10,
    MessageAttributeNames=[
        'All'
    ],
    VisibilityTimeout=0,
    WaitTimeSeconds=0
)

print(len(response['Messages']))

for index, message in enumerate(response['Messages']):
    print("Index Number: ", index)
    print(message)

    receipt_handle = message['ReceiptHandle']

    # do some function

    sqs.delete_message(
         QueueUrl=queue_url,
         ReceiptHandle=receipt_handle
    )

Upvotes: 4

Views: 3489

Answers (3)

Paritosh
Paritosh

Reputation: 61

Key points to understand regarding SQS:

  1. Visibility timeout
  2. Wait time seconds
  3. Receipt handle

When a message is received by a Lambda function, it gets a 'ReceiptHandle' for that receive. Now, this ReceiveHandle changes whenever a new lambda thread receives the message making the previous handler invalid.

Since VisibilityTimeout = 0 and WaitTimeSeconds = 0,(as pointed out by @Mandraenke), the message is immediately made available to another lambda thread with a new 'ReceiptHandle'.

The receipt 'ReceiptHandle' being processed by the previous lambda thread becomes invalid and could not be reached by the lambda function processing it.

Upvotes: 1

Mandraenke
Mandraenke

Reputation: 3266

You are setting VisibilityTimeout=0 and WaitTimeSeconds=0 - the message will timeout and become visible again after zero seconds.

This is probably not what you want - you should try with higher values here and read the docs about them: https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-visibility-timeout.html

You can time out the usual processing time and set the values to safe ones, so that messages will be delivered in case of errors.

Upvotes: 1

Marcin
Marcin

Reputation: 238051

Probably because you are using VisibilityTimeout=0. This means that the message immediately goes back to the SQS queue. So there is nothing to delete for you.

Upvotes: 3

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