Hydra Integration Module

Integrating third-party Node.js web frameworks with Hydra, the simplest way.

Hydra is a NodeJS package, which facilitates building distributed applications such as Microservices. (https://www.hydramicroservice.com/)

The magic thing with Hydra is that with a minimum setup, your micro-service get 'superpowers':

• Distributed Computing
• Application Clusters + Load Balancer
• High Availability
• Centralized Proxy Router
• Realtime Messaging
• Service Discovery, Monitoring and Management
• ... and much more (https://www.hydramicroservice.com/)

By using this module, you will be able to easily integrate your prefered web framework with hydra. Just keep reading...

Integrated frameworks

At the moment, the following frameworks are supported:

1. Express: Fast, unopinionated, minimalist web framework for Node.js... (http://expressjs.com/)
2. Hapi: A rich framework for building applications and services, hapi enables developers to focus on writing reusable application logic instead of spending time building infrastructure... (https://hapijs.com/)
3. Koa: Koa is a new web framework designed by the team behind Express, which aims to be a smaller, more expressive, and more robust foundation for web applications and APIs... (http://koajs.com/)
4. Sails.js: Sails makes it easy to build custom, enterprise-grade Node.js apps... (http://sailsjs.com/)
5. Restify: Restify is a node.js module built specifically to enable you to build correct REST web services... (http://restify.com/)
6. Restana: Super fast and minimalist web framework for building REST micro-services... (https://github.com/jkyberneees/ana)
7. Native Hydra Service: Hydra services are ideal for making distributed API calls through HTTP or real-time events management... (https://www.hydramicroservice.com/)

Getting Started

Next we will explain you how to create and express based micro-service on top of hydra:

IMPORTANT: Hydra depends on Redis database server for storage, cache and messaging. In case you don't have it yet: https://www.hydramicroservice.com/docs/quick-start/step1.html

1. Install dependencies:

npm i hydra hydra-integration express --save

Express is a dependency here because in the next example we use express, it could be koa or hapi, or any of the supported frameworks.

2. Create and edit app.js file:

const HydraServiceFactory = require('hydra-integration').HydraServiceFactory;
const express = require('express');
const router = express.Router();

const factory = new HydraServiceFactory({
    hydra: {
        'serviceName': 'express-service-test',
        'serviceDescription': 'Basic express service on top of Hydra',
        'serviceIP': '127.0.0.1',
        'servicePort': 3000,
        'serviceType': 'express',
        'serviceVersion': '1.0.0',
        'redis': {
            'host': '127.0.0.1',
            'port': 6379,
            'db': 15
        }
    }
});

factory.init().then(factory => factory.getService(service => {
    router.get('/welcome', (req, res) => res.send('Hello World!'));
    service.use('/v1', router);
}));

Alternative way of getting the service instance by passing config params to the builder (if supported):

factory.init().then(factory => factory.getService({
  // optional config params here to be passed to the building strategy
  bootstrap: service => {
    router.get('/welcome', (req, res) => res.send('Hello World!'));
    service.use('/v1', router);
  }
}));

To use hydra-integration as a plugin see: The HydraIntegrationPlugin class

3. Run your service:

• Single process:

node app.js

• Optionally you can run multiple processes with PM2:

pm2 start app.js -i 4

4. Test your service using a Web browser at: http://localhost:3000/v1/welcome
5. Test the service using the hydra-cli (https://www.hydramicroservice.com/docs/tools/hydra-cli/getting-started.html):

• List service routes

hydra-cli routes express-service-test

{
  "serviceName": [
    "[GET]/_health",
    "[GET]/v1/welcome"
  ]
}

• Invoke the [GET]/v1/welcome service endpoint:

hydra-cli rest express-service-test:[GET]/v1/welcome

{
  "headers": {
    "x-powered-by": "Express",
    "content-type": "text/html; charset=utf-8",
    "content-length": "12",
    "etag": "W/\"c-Lve95gjOVATpfV8EL5X4nxwjKHE\"",
    "date": "Wed, 05 Apr 2017 21:22:51 GMT",
    "connection": "close"
  },
  "body": "Hello World!",
  "statusCode": 200
}

Demos

Demos available into demos folder on the git repository: https://github.com/jkyberneees/hydra-integration

Next Topics

• The HydraServiceFactory class
• The HydraIntegrationPlugin class
• Express Framework Integration
• Hapi Framework Integration
• Koa Framework Integration
• Sails(0.x) Framework Integration
• Restify Framework Integration
• Restana Framework Integration
• Native Hydra Integration
• Creating your own integration
• Reference documentation

Complementary Topics

• The Hydra Router