Answersheet to 'Events: handling and receiving events'

// node/index.ts
import {
  LRUCache,
  Service,
  ServiceContext,
  ParamsContext,
  RecorderState,
  method,
} from '@vtex/api'
import { Clients } from './clients'
import { analytics } from './handler/analytics'
import { updateLiveUsers } from './events/liveUsersUpdate'

// Create a LRU memory cache for the Status client.
// The @vtex/api HttpClient respects Cache-Control headers and uses the provided cache.
const memoryCache = new LRUCache<string, any>({ max: 5000 })
metrics.trackCache('status', memoryCache)

const TREE_SECONDS_MS = 3 * 1000
const CONCURRENCY = 10

declare global {
  type Context = ServiceContext<Clients, State>

  interface State extends RecorderState {
    code: number
  }
}

export default new Service<Clients, State, ParamsContext>({
  clients: {
    implementation: Clients,
    options: {
      default: {
        retries: 2,
        timeout: 10000,
      },
      events: {
        exponentialTimeoutCoefficient: 2,
        exponentialBackoffCoefficient: 2,
        initialBackoffDelay: 50,
        retries: 1,
        timeout: TREE_SECONDS_MS,
        concurrency: CONCURRENCY,
      },
    },
  },
  routes: {
    analytics: method({
      GET: [analytics],
    }),
  },
  events: {
    liveUsersUpdate: updateLiveUsers,
  },
})

//node/event/liveUsersUpdate.ts
export async function updateLiveUsers() {
  console.log('EVENT HANDLER: received event')
}

// node/service.json
{
  "memory": 128,
  "ttl": 10,
  "timeout": 10,
  "minReplicas": 2,
  "maxReplicas": 10,
  "workers": 4,
  "events": {
    "liveUsersUpdate": {
      "sender": "vtex.events-example",
      "keys": ["send-event"]
    }
  },
  "routes": {
    "analytics": {
      "path": "/_v/app/analytics/realTime",
      "public": true
    }
  }
}