This project contains source code and supporting files for a serverless application that you can deploy with the SAM CLI. It includes the following files and folders.

• src - Folder that includes the Lambda functions of the application by folders for each Entity.
  • branch - Lambda functions for branches CRUD.
  • business - Lambda functions for business CRUD and compress_image function for logos.
  • businessLine - Lambda functions for businessLine CRUD.
  • item - Lambda functions for items CRUD.
• template.yaml - A template that defines the application's AWS resources.
  • This template includes:
    • Parameters for DynamoDB table names.
    • Globals for Lambda Functions that define Runtime, Architectures, Layers, Timeout and Memory Size.
    • Lambda Functions for the defined Entities.
    • Cognito User Pool for app users and API Authorizers. Includes:
      • Cognito User Pool Client configuration.
      • Cognito User Pool Domain configuration.
    • API REST that defines:
      • Custom Gateway error responses.
      • Configuration to enable CloudWatch logs.
      • Cognito authorizer for requests to the API linked to the defined Userpool.
      • Validation Models for the defined Entities.
    • API Configuration that define IAM Role to enable CloudWatchs logs in the API REST
    • S3 buckets with their associated policy.
      • A bucket for business logos(Public Access).
      • Abucket for load items from csv file(Restrict Access). The application uses several AWS resources, including Lambda functions and an API Gateway API. These resources are defined in the template.yaml file in this project. You can update the template to add AWS resources through the same deployment process that updates your application code.

The Serverless Application Model Command Line Interface (SAM CLI) is an extension of the AWS CLI that adds functionality for building and testing Lambda applications. It uses Docker to run your functions in an Amazon Linux environment that matches Lambda. It can also emulate your application's build environment and API.

To use the SAM CLI, you need the following tools.

• SAM CLI - Install the SAM CLI
• Node.js - Install Node.js 10, including the NPM package management tool.
• Docker - Install Docker community edition

To build and deploy your application for the first time, run the following in your shell:

sam build
sam deploy --guided

The first command will build the source of your application. The second command will package and deploy your application to AWS, with a series of prompts:

• Stack Name: The name of the stack to deploy to CloudFormation. This should be unique to your account and region, and a good starting point would be something matching your project name.
• AWS Region: The AWS region you want to deploy your app to.
• Parameters: The value for the AWS resources defined in the template.
• Confirm changes before deploy: If set to yes, any change sets will be shown to you before execution for manual review. If set to no, the AWS SAM CLI will automatically deploy application changes.
• Allow SAM CLI IAM role creation: Many AWS SAM templates, including this example, create AWS IAM roles required for the AWS Lambda function(s) included to access AWS services. By default, these are scoped down to minimum required permissions. To deploy an AWS CloudFormation stack which creates or modifies IAM roles, the CAPABILITY_IAM value for capabilities must be provided. If permission isn't provided through this prompt, to deploy this example you must explicitly pass --capabilities CAPABILITY_IAM to the sam deploy command.
• Save arguments to samconfig.toml: If set to yes, your choices will be saved to a configuration file inside the project, so that in the future you can just re-run sam deploy without parameters to deploy changes to your application.

You can find your API Gateway Endpoint URL in the output values displayed after deployment.

The application template uses AWS Serverless Application Model (AWS SAM) to define application resources. AWS SAM is an extension of AWS CloudFormation with a simpler syntax for configuring common serverless application resources such as functions, triggers, and APIs. For resources not included in the SAM specification, you can use standard AWS CloudFormation resource types.

To simplify troubleshooting, SAM CLI has a command called sam logs. sam logs lets you fetch logs generated by your deployed Lambda function from the command line. In addition to printing the logs on the terminal, this command has several nifty features to help you quickly find the bug.

NOTE: This command works for all AWS Lambda functions; not just the ones you deploy using SAM.

aws-sam-template$ sam logs -n HelloWorldFunction --stack-name aws-sam-template --tail

You can find more information and examples about filtering Lambda function logs in the SAM CLI Documentation.

Tests are not defined already. to implement: In the src/tests folder in this project. Use NPM to install the Mocha test framework and run unit tests.

aws-sam-template$ cd hello-world
hello-world$ npm install
hello-world$ npm run test

To delete the sample application that you created, use the AWS CLI. Assuming you used your project name for the stack name, you can run the following:

aws cloudformation delete-stack --stack-name aws-sam-template

See the AWS SAM developer guide for an introduction to SAM specification, the SAM CLI, and serverless application concepts.

Next, you can use AWS Serverless Application Repository to deploy ready to use Apps that go beyond hello world samples and learn how authors developed their applications: AWS Serverless Application Repository main page