msa_lab

이 프로젝트는 AWS SAM 및 기타 Serverless 관련 서비스들을 사용하여 MSA를 구성하는데 있어서 도움을 주고자 만들어진 프로젝트 입니다. 현재는 아래와 같인 폴더 구조로 되어 있습니다.

src/order - 주문에 대한 function
src/payment - 결제에 대한 function
events - 로컬에서 테스트를 수행하기 위한 event json을 모아놓은 폴더
src/test - 단위 테스르를 수행하는 폴더 모음.
template.yaml - 인프라에 대해서 정의하는 cloudformation
tsconfig.json - Typescript 사용을 위한 환경 설정
webpack.config.js - webpack 사용을 위한 환경 설정

현재 이 어플리케이션은 Typscript/Webpack이용해서 작성되었습니다. 현재 Lambda는 nodejs를 지원하지만 바로 typescript를 지원하고 있지는 않습니다. 실제 사용해 볼 경우, sam 빌드는 사용하는 것보다 webpack을 사용하는 것이 훨씬 최적화된 상태로 빌드하는 것을 볼 수 있습니다. 또한, Event Sorucing/Event Driven Development를 보여드리기 위해 SQS/API Gateway를 사용하고 있습니다.come.html)

Deploy the application

서버리스 애플리케이션을 효율적으로 구현하기 위해서 AWS SAM CLI를 사용했습니다. 이 CLI를 이용하면 Lambda를 로컬에서도 쉽게 테스트 해볼 수 있습니다. 이 CLI를 이용하기 위해서는 아래와 같은 패키들이 준비가 되어 있어야 합니다. DDB의 경우도 로컬에서 같이 확인할 수 있습니다.

AWS SAM CLI를 사용하기 위해서 미리 설치되어 있어야 하는 패키지들

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

이 어플리케이션을 빌드하고 배포하기 위해서는 아래와 같은 내용을 입력하시면 됩니다.

npm run 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 modified 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.

Use the SAM CLI to build and test locally

Build your application with the sam build command.

msa_lab$ sam build

The SAM CLI installs dependencies defined in hello-world/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.

msa_lab$ sam local invoke HelloWorldFunction --event events/event.json

The SAM CLI can also emulate your application's API. Use the sam local start-api to run the API locally on port 3000.

msa_lab$ sam local start-api
msa_lab$ curl http://localhost:3000/

The 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:
        HelloWorld:
          Type: Api
          Properties:
            Path: /hello
            Method: get

Add a resource to your application

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.

Fetch, tail, and filter Lambda function logs

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.

msa_lab$ sam logs -n HelloWorldFunction --stack-name msa_lab --tail

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

Unit tests

Tests are defined in the hello-world/tests folder in this project. Use NPM to install the Mocha test framework and run unit tests.

msa_lab$ cd hello-world
hello-world$ npm install
hello-world$ npm run test

Cleanup

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 msa_lab

Resources

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

nijin39/msa-lab