Node.js API with Serverless Framework in AWS Environment

This is an AWS cloud infrastructure builded with API Gateway, DynamoDB, AWS Lambda, and AWS CloudFormation using the Serverless framework for infrastructure development based on Infrastructure as Code.

Steps

Prerequisites:

• Have an AWS account and install Node.js on the machine.
• Install the AWS CLI: https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-welcome.html

Initial Setup

AWS Credentials

• Create a user: AWS Management Console -> IAM Dashboard -> Create New User -> -> Permissions "Administrator Access" -> Programmatic Access -> Download Keys
• In the terminal: $ aws configure -> paste the previously generated credentials

Set up the Serverless framework

$ npm i -g serverless

Project Development

$ serverless
Login/Register: No
Update: No
Type: Node.js REST API (V1) or Node.js HTTP API (V2)
Name: aws-serverless

$ cd aws-serverless
$ code .

• In the serverless.yml file, add the region region: us-east-1 within the provider: scope.
• Save and deploy $ serverless deploy -v

Code Structure

• Create the "src" directory and move the "handler.js" file into it.
• Rename the "handler.js" to "hello.js"
• Update the code:

const hello = async (event) => {
/////
module.exports = {
    handler:hello
}

• Update the "serverless.yml" file:

handler: src/hello.handler

$ serverless deploy -v

DynamoDB

Update the serverless.yml file:

resources:
  Resources:
    ItemTable:
      Type: AWS::DynamoDB::Table
      Properties:
          TableName: ItemTable
          BillingMode: PAY_PER_REQUEST
          AttributeDefinitions:
            - AttributeName: id
              AttributeType: S
          KeySchema:
            - AttributeName: id
              KeyType: HASH

Develop Lambda Functions

- Folder  /src in the repository.
- Get the ARN of the table in DynamoDB AWS Console -> DynamoDB -> Overview -> Amazon Resource Name (ARN).
- Update the serverless.yml file with the following code, below ```region:```

  iam:
    role:
        statements:
          - Effect: Allow
            Action:
              - dynamodb:PutItem
              - dynamodb:UpdateItem
              - dynamodb:GetItem
              - dynamodb:Scan
            Resource:
              - arn:aws:dynamodb:us-east-1:167880115321:table/ItemTable

• Install dependencies:

npm init npm i uuid aws-sdk

• Update the list of functions in the serverless.yml file:

functions:
hello:
  handler: src/hello.handler
  events:
    - http:
        path: /
        method: get
insertItem:
  handler: src/insertItem.handler
  events:
    - http:
        path: /item
        method: post
fetchItems:
  handler: src/fetchItems.handler
  events:
    - http:
        path: /items
        method: get
fetchItem:
  handler: src/fetchItem.handler
  events:
    - http:
        path: /items/{id}
        method: get
updateItem:
  handler: src/updateItem.handler
  events:
    - http:
        path: /items/{id}
        method: put

Serverless Framework Node HTTP API on AWS

This template demonstrates how to make a simple HTTP API with Node.js running on AWS Lambda and API Gateway using the Serverless Framework.

This template does not include any kind of persistence (database). For more advanced examples, check out the serverless/examples repository which includes Typescript, Mongo, DynamoDB and other examples.

Usage

Deployment

$ serverless deploy

After deploying, you should see output similar to:

Deploying aws-node-http-api-project to stage dev (us-east-1)

✔ Service deployed to stack aws-node-http-api-project-dev (152s)

endpoint: GET - https://xxxxxxxxxx.execute-api.us-east-1.amazonaws.com/
functions:
  hello: aws-node-http-api-project-dev-hello (1.9 kB)

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 http 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 response similar to the following (removed input content for brevity):

{
  "message": "Go Serverless v2.0! Your function executed successfully!",
  "input": {
    ...
  }
}

Local development

You can invoke your function locally by using the following command:

serverless invoke local --function hello

Which should result in response similar to the following:

{
  "statusCode": 200,
  "body": "{\n  \"message\": \"Go Serverless v3.0! Your function executed successfully!\",\n  \"input\": \"\"\n}"
}

Alternatively, 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.