Serverless - AWS Node.js Typescript, DynamoDB Sample Project

This project has been generated using the aws-nodejs-typescript template from the Serverless framework.

For detailed instructions, please refer to the documentation.

TODOs:

• Enable deployment to different Serverless environments from CI/CD

Notes on CI/CD:

This project is setup so that it will run the test_and_deploy.yml workflow on a push to the staging branch or on a successful PR to the main branch.

It does NOT as of yet support deployment to different environments so it just deploys to the dev one by default. It will run a local Dynamo in CI, run the tests, and finally (if uncommented) will deploy to AWS.

Installation/deployment instructions

Depending on your preferred package manager, follow the instructions below to deploy your project.

Requirements: NodeJS lts/fermium (v.14.15.0). If you're using nvm, run nvm use to ensure you're using the same Node version in local and in your lambda's runtime.

Installing and deploying

• Run yarn install to install the project dependencies
• Run yarn sls deploy (or just sls deploy if you have serverless install globally on your machine) to deploy this stack to AWS

Testing

This projects currently has only 1 test suite of integration tests (src/services/Todo/service.int.test.ts) written. This is because it's a demo project and the tests are integration tests because this is a Serverless architecture which means that instead of using the normal testing pyramid (E2E < Integration < Unit) we instead should be using a testing hexagon (E2E < Integration > Unit) as the primary goal of such APIs typically is to leverage different services (integrations) and this means that having most of the tests focus on those integrations makes more sense than having mostly unit tests.

• Run yarn test:int to run the integration tests

This will start up a local DynamoDB container to execute the tests against. After the tests complete/fail the cleanup script will destroy the container.

There are also sample global Jest setup and teardown files in the root. jest.int.setup.ts will take care of creating the necessary Dynamo tables and then jest.int.teardown.ts will take care of deleting them (although in this use case this doesn't matter because we destroy the container after the tests anyway but it's a good example).

I've provided two different configuration files for unit (jest.unit.config.ts) and integration (jest.int.config.ts) testing.

3rd party libraries

• json-schema-to-ts - uses JSON-Schema definitions used by API Gateway for HTTP request validation to statically generate TypeScript types in your lambda's handler code base
• middy - middleware engine for Node.Js lambda. No middlewares have been used in this example.
• @serverless/typescript - provides up-to-date TypeScript definitions for your serverless.ts service file

Advanced usage

Any tsconfig.json can be used, but if you do, set the environment variable TS_NODE_CONFIG for building the application, eg TS_NODE_CONFIG=./tsconfig.app.json npx serverless webpack