Echoes

Echoes is an abstraction of kafkajs. It can be used as a standalone package without installing other orionjs packages.

Install package

npm

npm install @orion-js/echoes

Yarn

yarn add @orion-js/echoes

startService

See Client configuration for client params. See Consuming messages for consumer params. See Producing messages for producer params.

echoes is an object containing all of the service echo

import {startService} from '@orion-js/echoes'
import echoes from 'app/components/echoes'
import {route} from '@orion-js/app'

startService({
  client: {
    clientId: 'appName',
    brokers: ['localhost:9092']
  },
  consumer: {
    groupId: 'microserviceId'
  },
  producer: {},
  requests: {
    key: 'secretPassword',
    startHandler: handler => route('/echoes-services', handler),
    services: {
      example: 'http://localhost:4100/echoes-services'
    }
  },
  echoes
})

echo

An echo is a message handler. You can define multiple echoes in your app. All must be passed in the echoes param of startService. The key in the echoes params will be the name of the topic. An echo definition must have 2 params. type and resolve:

Type can be echo.types.event or echo.types.request.

You must pass a resolve function, which has 2 arguments.

• params: The params passed when this event is called
• context: Contains the arguments in the eachMessage Kafkajs function

import {echo} from '@orion-js/echoes'

export default echo({
  type: echo.types.event,
  async resolve(params, context) {
    console.log('Received an event', params)
  }
})

publish

Publish sends a message that doesn't expects a response. It expects the following params:

• topic: Topic (echo) to send the message to
• params: The params that the echo will receive. This params are serialized using serialize-javascript so you can pass all JavaScript basic types (not including functions).
• ack: See Producing ack
• timeout: See Producing timeout

import {publish} from '@orion-js/echoes'

await publish({
  topic: 'onEvent',
  params: {
    hello: 'world',
    date: new Date(),
    number: 134433,
    bool: true,
    regexp: /alsothis/gi
  }
})

request

Publish sends a http request that expects an instant response. It expects the following params:

• method: Topic (echo) to send the message to
• service: Service name that has an url mapped on the startService function.
• params: The params that the echo will receive. This params are serialized using serialize-javascript so you can pass all JavaScript basic types (not including functions).

import {request} from '@orion-js/echoes'

await request({
  service: 'example',
  method: 'getResponse',
  params: {
    hello: 'world',
    date: new Date(),
    number: 134433,
    bool: true,
    regexp: /alsothis/gi
  }
})