@persona/infra

a collection of in-house infrastructure and tooling for the Persona project

Installation

Install with NPM via Git:

$ npm install -S https://github.com/project-persona/infra.git

Remember to update the package when new version rolls out:

$ npm update @persona/infra

Service Broker

a Zero-MQ powered service-oriented message queue in many-to-many request/reply pattern, based on Majordomo Protocol (7/MDP).

Basically JSON-RPC 2.0 (with tweaks) over 7/MDP. For more information, see documentation. Note: heartbeat and down detection currently not implemented due to time constraints.

Configurations

Optional environment variables:

Key	Type	Description	Default
BROKER_ADDR	string	the ZMQ address for broker to listen and for clients/workers to connect	tcp://0.0.0.0:5555

Examples

Starting the Broker

The broker is designed to run standalone in a separate process. Workers can join or leave a service set at any moment.

It is recommended to start the bus itself before any worker/client.

To start a bus process:

$ npm run start-broker

Worker Process

const { RpcWorker, RpcProvider } = require('@persona/infra/service-broker')
new RpcWorker('serviceName', class extends RpcProvider {
  // a service-wide initializer: this hook will only run once for a service
  async [RpcProvider.init] () {
    // TODO: your code here...
  }

  // a request-scoped before hook: this hook runs for every request before your actually method
  async [RpcProvider.before] () {
    // TODO: your code here...
  }

  // your actual method: name this function whatever your like as long as it's human readable
  async methodName (a, b) {
    // TODO: your code here...
  }

  // a request-scoped after hook: this hook runs for every request after your actually method
  async [RpcProvider.after] () {
    // TODO: your code here...
  }
}, 'tcp://0.0.0.0:5555').start()

Client Process

const client = RpcClient.create(address, optionalContext)
await client.serviceName.methodName(a, b)

You normally don't create client instances from scratch. When implementing a microservice, use the RpcProvider#services and RpcProvider#systemServices injections:

new RpcWorker('serviceName', class extends RpcProvider {
  async methodName (a, b) {
    return this.services.anotherServiceName.anotherMethodName(a, b)
    // or, use systemServices to call from a system context:
    // return this.systemServices.anotherServiceName.anotherMethodName(a, b)
  }
}, 'tcp://0.0.0.0:5555').start()

Gateway

a JSON-RPC 2.0 over HTTP gateway exposing microservices connected to the service bus

Examples

Starting the Gateway

The bus is designed to run standalone in a separate process.

It is recommended to start the gateway after the bus has started.

To start a bus process:

$ npm run start-gateway

Optional environment variables:

Key	Type	Description	Default
PORT	integer	the port number of the http server	8080
HOST	string	the host of the http server	0.0.0.0
BROKER_ADDR	string	the ZMQ address for broker to listen and for clients/workers to connect	tcp://0.0.0.0:5555

Client

A JavaScript web SDK to access microservices connected to the service bus via JSON-RPC HTTP gateway.

Examples

import firebase from 'firebase'
import { Client } from '@persona/infra/web-sdk'

const app = firebase.initializeApp({ ... })
const client = Client.create(app, optionalGatewayUrl)
await client.yourService.yourMethod(a, b)

Creating a Client Instance