How can this be accomplished?
Use AWS CloudFormation with a Lambda-backed custom resource to provision API Gateway. Use the AWS::DynamoDB::Table and AWS::Lambda::Function resources to create the Amazon DynamoDB table and Lambda functions. Write a script to automate the deployment of the CloudFormation template.
Use the AWS Serverless Application Model to define the resources. Upload a YAML template and application files to the code repository. Use AWS CodePipeline to connect to the code repository and to create an action to build using AWS CodeBuild. Use the AWS CloudFormation deployment provider in CodePipeline to deploy the solution.
Use AWS CloudFormation to define the serverless application. Implement versioning on the Lambda functions and create aliases to point to the versions. When deploying, configure weights to implement shifting traffic to the newest version, and gradually update the weights as traffic moves over.
Commit the application code to the AWS CodeCommit code repository. Use AWS CodePipeline and connect to the CodeCommit code repository. Use AWS CodeBuild to build and deploy the Lambda functions using AWS CodeDeploy. Specify the deployment preference type in CodeDeploy to gradually shift traffic over to the new version.
Explanations:
Although AWS CloudFormation can be used to provision resources, using a Lambda-backed custom resource to provision API Gateway adds unnecessary complexity and is not the most straightforward approach for automating serverless deployments.
The AWS Serverless Application Model (SAM) is designed for serverless applications. It simplifies the process of defining and deploying serverless resources. Integrating SAM with CodePipeline and CodeBuild automates the deployment effectively.
AWS CloudFormation can define the serverless application, but the focus on Lambda versioning and aliasing does not directly automate the entire deployment process for serverless APIs in the context of this scenario. It is a less optimal solution.
This approach using AWS CodeDeploy to manage Lambda function deployment with gradual traffic shifting is suited for updating Lambda functions but does not directly address automating the deployment of the entire serverless application, including API Gateway and DynamoDB.
From my perspective, the answer is:
Use the AWS Serverless Application Model to define the resources. Upload a YAML template and application files to the code repository. Use AWS CodePipeline to connect to the code repository and to create an action to build using AWS CodeBuild. Use the AWS CloudFormation deployment provider in CodePipeline to deploy the solution.