Povery

Povery is a framework for building things on AWS Lambda with Typescript.

It's heavily opinionated.

You can serve many lambdas as an http server, or you can invoke them locally from the terminal.

Unlike other things like this, it does not want to create lamdas for you (just deploy them, if you wish)

Rules

• Every lambda has a named folder under lambda folder.
• The entrypoint of the lambda MUST BE index.ts file.
• Lambdas that serve API Gateway SHOULD BE prefixed with API_ (e.g. API_Something) and start with a capital letter.
• Lambdas that serve ant other events SHOULD BE prefixed with EVENT_ (e.g. EVENT_Something) and start with a capital letter.
• API Gateway MUST USE proxy integration to respond to api request.

Install

npm i povery

Create a new project

povery init

Example:

/<project_root>
  lambda/
    API_Something/
      index.ts
    EVENT_Something/
      index.ts
      event.json

The CLI

Start a web server

Configure povery.json file with the routes you need.

// povery.json
{
  "lambdas": {
    "API_Something": [
      {
        "method": "ANY",
        "path": "/{proxy+}"
      }
    ]
  }
}

Then run:

povery start

Invoke a lambda locally

It runs your ts code with the json file event.json in the lambda folder.

povery function invoke EVENT_Something

The framework

Api Gateway

This is an example index.ts to respond to an API Gateway request:

// index.ts
import {povery, controller, api} from 'povery'

@controller
class Service {

    @api('GET', /hello')
    hello() {
        return 'hello world'
    }
}

exports.handler = povery.load(Service);

A lambda with this code can also be called in a RPC fashion

// index.ts
const aws = require('aws-sdk');
const lambda = new aws.Lambda();

await lambda.invoke({
    FunctionName: 'my-service',
    Payload: JSON.stringify({
        action: 'hello',
        payload: {}
    })
}).promise();

AWS Events

This is how to react to AWS events:

// index.ts
import {povery, controller, api} from 'povery'
async function handler(event, context) {
    // DO SOMETHING
}

exports.handler = povery.forAwsEvent.load(handler);

JWT Authorization

Povery supports JWT authorization. Authentication must be done on APi Gateway, and the token must be passed to the lambda as a header.

Using withAuth, povery checks for custom:role claims and mathes it with the roles you pass to the decorator.

// index.ts
@controller
class Service {

    // only admin can access
    @api('GET', /hello')
    @acl(['ADMIN'])
    hello() {
        return 'hello world'
    }
}

exports.handler = povery.withAuth().load(Service);

See "Autorization" section in povery.json for more details.