How should the DevOps engineer overcome this?
Add a BeforeAllowTraffic hook to the AppSpec file that tests and waits for any necessary database changes before traffic can flow to the new version of the Lambda function.
Add an AfterAllowTraffic hook to the AppSpec file that forces traffic to wait for any pending database changes before allowing the new version of the Lambda function to respond.
Add a BeforeInstall hook to the AppSpec file that tests and waits for any necessary database changes before deploying the new version of the Lambda function.
Add a ValidateService hook to the AppSpec file that inspects incoming traffic and rejects the payload if dependent services, such as the database, are not yet ready.
Explanations:
Adding a BeforeAllowTraffic hook allows for a check to ensure that the database changes have fully propagated before any traffic is directed to the new version of the Lambda function. This ensures that users do not experience failures due to incomplete database updates.
An AfterAllowTraffic hook would not be suitable as it allows traffic to flow before validating whether the database changes are complete. This could still lead to failures if the database is not ready to handle requests after deployment.
A BeforeInstall hook is not appropriate because it executes before the new version of the Lambda function is deployed. This means it would not be able to prevent traffic from reaching the new version if database changes are still propagating.
A ValidateService hook checks the service health and can reject traffic, but it does not prevent the Lambda function from being deployed. If the database changes are not ready at this point, the function could still experience failures upon invocation, which is the core issue.
I have a feeling that the answer is:
Add a BeforeAllowTraffic hook to the AppSpec file that tests and waits for any necessary database changes before traffic can flow to the new version of the Lambda function.