SQS does not delete the message and runs infinite loop-CodePudding

I am new to AWS SQS. I am trying to implement a simple server to node SQS service where multiple nodes send some information (Some identification about itself) to the server, which the server needs to put in a list and delete the messages iteratively. I have the following code:

sqs_client = boto3.client("sqs",aws_access_key_id=akey,aws_secret_access_key=skey,region_name=region)

#Queue URL
queue=r'https://ap-south-1.queue.amazonaws.com/blahblah/SQS_client_list'

response = sqs_client.receive_message(
QueueUrl=queue,
AttributeNames=['SentTimestamp'],
MaxNumberOfMessages=10,
MessageAttributeNames=['All'],
VisibilityTimeout=2,
WaitTimeSeconds=2
)
message=response.get("Messages")
#Information should go into this list
node_list=[]

#Function to delete messages
#I need to delete the message after passing into the list "node_list"
def get_node_list():
    message_body = message[0]["Body"]
    node_list.append(message_body)
    sqs_client.delete_message(QueueUrl=queue, ReceiptHandle=response['Messages'][0]["ReceiptHandle"]) 
    time.sleep(3)
    return node_list

# Loop to delete all messages
while(True):
    if len(response.get('Messages', [])) !=0:
        time.sleep(3)
        get_node_list()
    if len(response.get('Messages', [])) ==0:
        break
print(node_list)

The issue is that when multiple nodes push their information into the same queue, this code runs an infinite loop and node_list gets append infinite number of times whereas the while loop does not delete the SQS message. What can possibly be wrong in the code?

CodePudding user response：

Your code should look like:

while(True):

  # Get messages
  response = sqs_client.receive_message(WaitTimeSeconds=20,...)

  # Loop through messages
  for message in response['Messages']:

    # process message here

    # Delete the message
    sqs_client.delete_message(QueueUrl=queue, ReceiptHandle=message['ReceiptHandle'])

I am assuming that you want it to be able to continually process new messages, hence the outer loop that loops forever.

When calling receive_messages(), I recommend that you set WaitTimeSeconds=20. This means that if there are no messages in the queue, it will wait up to 20 seconds before returning. However, as soon as a message appears, it will return without waiting 20 seconds. This reduces the number of API calls to AWS.

I notice that you have specified MaxNumberOfMessages=10, which means that multiple messages might be received. Therefore the code needs to loop through each of the messages provided.

After processing the message, it can call delete_message(). Alternatively, you could add all message handles to a list and call delete_message_batch() after the inner loop.