qgrail-broker

Broker to connect each services in qgrail project.

Install using npm

npm install --save qgrail-broker

qgrail-broker has 3 major components:

• Broker
• Service
• Client

Broker

To create broker is just as simple as this:

const QBroker = require("qgrail-broker");
const Broker = QBroker.Broker;

const broker = new Broker({
    bind_address: "tcp://127.0.0.1:30000",
    services: [
        {
            name: "calc",
            upstream: [
                "tcp://127.0.0.1:30001",
                "tcp://127.0.0.1:30002",
                "tcp://127.0.0.1:30003"
            ]
        }
    ],
    log: (type, data) => {
        console.log("TYPE: ", type);
        console.log("REQ: ", data);
    }
});

process.on("SIGINT", () => {
    console.log("BROKER TERMINATED");
    broker.close();
});


broker.listen(() => {
    console.log("Broker listen at port 30000");
});

This will create broker that bind at tcp://127.0.0.1:30000, and has service calc that will available at 3 ports 30001, 30002, 30003.

The broker will load balancing at those 3 ports if there is request to calc service.

Service

To create service you just need to do this:

const Promise = require("bluebird");

const QBroker = require("qgrail-broker");
const Service = QBroker.Service;

const ServiceCalc = new Service("tcp://0.0.0.0:30001", {
    log: (type, data) => {
        console.log("TYPE: ", type);
        console.log("REQ: ", data);
    }
});

ServiceCalc.func("add", ({a, b}) => {
    return a + b;
});

ServiceCalc.func("add-async", ({a, b}) => {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve(a + b);
        }, 300);
    })
})

ServiceCalc.listen(() => {
    console.log("service-calc-node-01 listen at port 30001");
});

So after creating the service, then just define all functions you want, and create normal function.

You can return any object, including Promise object for async process.

NOTE: function parameter will only an object, that contain all parameter. I use object here so you don't need to confuse about the parameters sequences. NOTE: you need to define all function before starting to listen.

Client

To connect with the service, you need a client. You can define client with this:

const QBroker = require("qgrail-broker");
const Client = QBroker.Client;

const ClientCalc = new Client("tcp://127.0.0.1:30000", "calc");

const sent = function(a, b) {
    ClientCalc.invoke("add", {a, b})
        .then((result) => {
            console.log(`add: ${a} + ${b} = ${result}`);
        });

    ClientCalc.invoke("add-async", {a, b})
        .then((result) => {
            console.log(`add-async: ${a} + ${b} = ${result}`);
        })
};

for(let a = 0; a < 10; a++) {
    for(let b = 0; b < 10; b++) {
        sent(a, b);
    }
}

So first you need to create new Client object by passing broker's address and what service you want to connect.

To invoke the function just need to call invoke method by passing fn and params object.

Return value of function will be at result.

Version note:

• 0.0.1: can work great for non high traffics (around 100 request per sec).