sam-rest-test

Testing a RESTful CRUD API backed by DynamoDB managed via SAM.

Structure

api contains the lambda functions that run in AWS API Gateway
app contains the frontend react app
template.yaml contains the sam template for the project structure in AWS

Setup

Install node 12, docker, jq, sam-cli (yeah, asks for homebrew), aws cli, and optionally the VSCode plugin
Run npm install in the package root, and inside api and app
Run npm run build (or npm run watch) at the project root to build the api (output should be in api/build)

Deploying to AWS

Run sam deploy --guided to deploy to AWS (please remember to use the AWS development account), you'll need to re-run this every time you modify your lambda code or the content of the template
Run npm run dev:create-user to create a user sample@example.com with password password in the user pool
Run npm run dev:export-stack to write a local app/src/aws.json file with the IDs of the resources created in AWS that will be used by the react app

Running the app

Run npm run start in the app folder
Note that the REGION in the app is hardcoded to us-east-1, change it in app/src/index.ts if needed

Running locally

Run npm run dev:start-db to start a docker container with a local dynamodb
Run npm run dev:create-tables to create local tables using the schema in scripts/create-tables.sh (ideally, this schema should be loaded from the template.yaml instead)
Run npm run dev:start-api to start a local version of the API gateway using sam
Run the app pointing to the local api with npm run start-local in the app folder

You can also try out the following requests:

# Create a relayer
curl -XPOST 'http://localhost:4000/relayers' -d '{ "relayerId": "1", "tenantId": "DEFAULT_TENANT", "name": "relayer1" }' -H "Content-Type: application/json"
# Get the relayer created
curl 'http://localhost:4000/relayers/1'
# List all relayers
curl 'http://localhost:4000/relayers'

Also, note that the react-app will try to connect to the cognito user pool for auth. This means you need to deploy to AWS before running the app locally. If you want to skip this and run everything locally, remove the authorization custom_header from app/src/index.ts, and the call to withAuthenticator in app/src/App.ts.

Next steps

Find out a better way to define env variables for local testing, that don't require adding the name of each function in api/envs/dev.json
Split the template.yaml into several templates, in order to separate the resources updated frequently (eg lambdas) and the more permanent resources (eg cognito)
Use a custom lambda authorizer to load the tenant info, and wrap the Dynamo client in an IAM role restricted to the current tenant (see this article)
Setup unit tests for lambdas using jest-dynamodb or jest-dynalite
Set up a CI/CD using CircleCI or Github actions
Set up a deployment step to S3 for the built react-app
Try out local lambda debugging

stevenlanders / sam-rest-test