Which solution will meet this requirement with the LEAST effort?
Move the call to the third-party dependency into an exception handling block. Write the message back to the SQS queue if a failure in the third-party dependency is caught in the exception handler.
Update the code in the Lambda function to remove calls to the SQS SDK ReceiveMessage function. Configure the Lambda function to use the SQS queue as an event source. Set the maxReceiveCount value on the SQS queue’s redrive policy to at least 5.
Create a second SQS queue to use as a dead-letter queue. Configure a redrive policy on the original SQS queue to send failed messages to the dead-letter queue. Modify the Lambda function to read messages from both queues.
Create a second SQS queue to use as a dead-letter queue. Move the call to the third-party dependency into an exception handling block. Write the message to the dead-letter queue if a failure in the third-party dependency is caught in the exception handler.
Explanations:
Moving the call to the third-party dependency into an exception handling block and writing the message back to the SQS queue does not provide a reliable solution. Retries in SQS are not guaranteed, and simply writing messages back after failure does not solve the problem of ensuring success.
Updating the Lambda function to use the SQS queue as an event source and setting the maxReceiveCount to 5 may not be enough to ensure successful message processing, especially if the issue is due to external dependencies. This approach focuses on retries but doesn’t handle message processing failure due to the dependency.
Adding a dead-letter queue and a redrive policy allows for tracking failed messages, but it doesn’t ensure that the Lambda function will successfully process messages. It only moves failed messages out of the processing cycle, which doesn’t address retrying or handling transient failures of the third-party dependency.
This approach uses a dead-letter queue to capture failed messages, which is useful for tracking failures. Additionally, moving the third-party dependency call into an exception block ensures that the message is handled properly in case of failure. This solution improves reliability by enabling retries for transient errors and ensuring that failed messages are not lost.
From my perspective, the answer is:
Create a second SQS queue to use as a dead-letter queue. Move the call to the third-party dependency into an exception handling block. Write the message to the dead-letter queue if a failure in the third-party dependency is caught in the exception handler.