emittableevent

EmittableEvent

EmittableEvent is an opinionated abstraction class for generating rich EventBridge events.

---

Note that EmittableEvent is primarily meant to function in an AWS Lambda context, however it will function just fine also outside of one but will be missing certain metadata.

For a great complementary solution for a Domain Event Publisher and an Event Emitter abstraction using EmittableEvent, see my related Gist.

Usage

Basic importing and usage

// ES5 format
const { EmittableEvent } = require('emittableevent');
// ES6 format
import { EmittableEvent } from 'emittableevent';

class MyEvent extends EmittableEvent {
  // Do something here if you want, else just leave it as is!
}

const event = new MyEvent(eventInput, awsRequestContext);

Demo

// Your own event class
class MyEvent extends EmittableEvent {
  // Do something here if you want, else just leave it as is!
}

// Convenience utility to produce required static metadata
const getMetadataConfig = (version = 1) => {
  return {
    version,
    eventType: 'DomainEvent',
    domain: 'MyDomain',
    system: 'MySystem',
    service: 'MyService',
    team: 'MyTeam',
    hostPlatform: 'aws',
    owner: 'Sam Person',
    jurisdiction: 'eu'
  };
};

// Input for actually creating the event
const eventInput = {
  eventName: 'MyEvent',
  eventBusName: 'MyEventBus',
  data: {
    something: 'some value here if you want'
  },
  metadataConfig: getMetadataConfig()
};

// Create the event
const event = new MyEvent(eventInput, requestContext);

// ...and here's the actual full body of the event
console.log(event.get());

The event will look similar to:

{
  "EventBusName": "MyEventBus",
  "Source": "mydomain.mysystem.myevent",
  "DetailType": "MyEvent",
  "Detail": "{\"metadata\":{\"version\":1,\"eventType\":\"DomainEvent\",\"domain\":\"MyDomain\",\"system\":\"MySystem\",\"service\":\"MyService\",\"team\":\"MyTeam\",\"hostPlatform\":\"aws\",\"owner\":\"Sam Person\",\"jurisdiction\":\"eu\",\"eventName\":\"MyEvent\",\"correlationId\":\"26dd1faf-a901-4413-92db-9e09b7915a3c\",\"resource\":\"/\",\"accountId\":\"123412341234\",\"runtime\":\"\",\"functionName\":\"\",\"functionMemorySize\":\"\",\"functionVersion\":\"\",\"lifecycleStage\":\"dev\",\"region\":\"\"},\"data\":{\"something\":\"some value here\"}}"
}