Serverless Framework Node Express API on AWS

This template demonstrates how to develop and deploy a simple Node Express API service running on AWS Lambda using the traditional Serverless Framework.

Anatomy of the template

This template configures a single function, api, which is responsible for handling all incoming requests thanks to the httpApi event. To learn more about httpApi event configuration options, please refer to httpApi event docs. As the event is configured in a way to accept all incoming requests, express framework is responsible for routing and handling requests internally. Implementation takes advantage of serverless-http package, which allows you to wrap existing express applications. To learn more about serverless-http, please refer to corresponding GitHub repository.

Usage

Deployment

Install dependencies with:

npm install

and then deploy with:

serverless deploy

After running deploy, you should see output similar to:

Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
........
Serverless: Stack create finished...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service aws-node-express-api.zip file to S3 (711.23 KB)...
Serverless: Validating template...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
.................................
Serverless: Stack update finished...
Service Information
service: aws-node-express-api
stage: dev
region: us-east-1
stack: aws-node-express-api-dev
resources: 12
api keys:
  None
endpoints:
  ANY - https://xxxxxxx.execute-api.us-east-1.amazonaws.com/
functions:
  api: aws-node-express-api-dev-api
layers:
  None

Note: In current form, after deployment, your API is public and can be invoked by anyone. For production deployments, you might want to configure an authorizer. For details on how to do that, refer to httpApi event docs.

Invocation

After successful deployment, you can call the created application via HTTP:

curl https://xxxxxxx.execute-api.us-east-1.amazonaws.com/

Which should result in the following response:

{"message":"Hello from root!"}

Calling the /hello path with:

curl https://xxxxxxx.execute-api.us-east-1.amazonaws.com/hello

Should result in the following response:

{"message":"Hello from path!"}

If you try to invoke a path or method that does not have a configured handler, e.g. with:

curl https://xxxxxxx.execute-api.us-east-1.amazonaws.com/nonexistent

You should receive the following response:

{"error":"Not Found"}

Local development

It is also possible to emulate API Gateway and Lambda locally by using serverless-offline plugin. In order to do that, execute the following command:

serverless plugin install -n serverless-offline

It will add the serverless-offline plugin to devDependencies in package.json file as well as will add it to plugins in serverless.yml.

After installation, you can start local emulation with:

serverless offline

To learn more about the capabilities of serverless-offline, please refer to its GitHub repository.