This project contains source code and supporting files for a serverless application that you can deploy with the AWS Serverless Application Model (AWS SAM) command line interface (CLI). It includes the following files and folders:
src
- Code for the application's Lambda function.events
- Invocation events that you can use to invoke the function.__tests__
- Unit tests for the application code.template.yaml
- A template that defines the application's AWS resources.
The AWS 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 AWS SAM CLI, you need the following tools:
- AWS SAM CLI - Install the AWS SAM CLI.
- Node.js - Install Node.js 16, 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.
- 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 forcapabilities
must be provided. If permission isn't provided through this prompt, to deploy this example you must explicitly pass--capabilities CAPABILITY_IAM
to thesam 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.
The API Gateway endpoint API will be displayed in the outputs when the deployment is complete.
Build your application by using the sam build
command.
my-application$ sam build
The AWS SAM CLI installs dependencies that are defined in package.json
, creates a deployment package, and saves it in the .aws-sam/build
folder.
Test a single function by invoking it directly with a test event. An event is a JSON document that represents the input that the function receives from the event source. Test events are included in the events
folder in this project.
Run functions locally and invoke them with the sam local invoke
command.
my-application$ sam local invoke putItemFunction --event events/event-get-chat-gpt-prompt.json
The AWS SAM CLI can also emulate your application's API. Use the sam local start-api
command to run the API locally on port 3000.
my-application$ sam local start-api
my-application$ curl http://localhost:3000/
The AWS SAM CLI reads the application template to determine the API's routes and the functions that they invoke. The Events
property on each function's definition includes the route and method for each path.
Events:
Api:
Type: Api
Properties:
Path: /getPrompt
Method: POST
The application template uses 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 that aren't included in the AWS SAM specification, you can use the standard AWS CloudFormation resource types.
my-application$ sam deploy
I have added AWS secret manager to save the chat-gpt API key as a secret value. Right now I have not added the code to populate the key dynamically in the secret manager. You have to add the key in the AWS SecretManager manually.