Deploying with sam deploy requires a full CloudFormation deployment every time you want to test a code change. This is great if you have a stable application or are deploying to production, but not so much during active development. Any change to your business logic or AWS SDK calls has to go through a CloudFormation stack update. Of course, business logic can be tested using unit tests, but how do we test AWS SDK calls from Lambda to DynamoDB? Deploying to AWS every time using sam deploy takes a long time and reduces development velocity.
SAM Accelerate isn’t only limited to Lambda code changes, it can also automate deployment of infrastructure changes in template.yaml through CloudFormation.
sam sync --watch --stack-name sam-app