Building Microservices with Gradle

A microservice architecture consisting of 3 microservices that interact with each other in Spring Boot using Gradle in Java 8

Open and view the Project using the .zip file provided or at my Github Repository

Table of Contents

• Getting Started
  • Tools Required
  • Installation
• Development
  • 1. Microservice architecture with Hardcoded Data
  • 2. Microservice architecture with an embedded Database
  • 3. Microservice architecture with an embedded Database and eureka as service discovery
  • 4. Dockerized Microservice architecture with an embedded Database and eureka as service discovery
• Running the App
• Resources

Getting Started

The project has 5 branches: master, hard-coding, mongo, eureka and docker

• master contains aggregate code of all branches
• hard-coding contains hardcoded data for APIs
• mongo contains embedded mongodb connection with the services
• eureka contains service discovery for the microservices
• docker contains a dockerized version of the app

This application doesn't have a proper UI and focuses on the Backend and the Database part

Tools Required

You would require the following tools to develop and run the project:

• MongoDB
• Docker
• Java 8
• SpringBoot
• Gradle
• A text editor or an IDE (like IntelliJ)

Installation

• Setup Java 8

  • Follow the steps mentioned here

• Install Gradle in your system. It’s highly recommended to use an installer:

  • SDKMAN
  • Homebrew

  As a last resort, if neither of these tools suit your needs, you can download the binaries from Gradle Org

• Setup MongoDB

  • Follow the steps mentionedhere

Development

1. Microservice architecture with Hardcoded Data

• Create 3 different project using Spring Initializr.
• Create resources and model classes for all of them.
• Building movie catalog service API, movie info service API and rating data service API.
• Creating replicas in the movie catalog service for the classes used in the services other two services.
• Have movie catalog service API call the other two services.
• The code will be in the master branch.

2. Microservice architecture with an embedded Database

• The services created in the previous step will be used to create an architecture with embedded DB.The hardcoded data will be removed from the app.
• The code will be in the mongo branch.
• Two databases have been created, one for each Movie-Info-Service and Rating-data-Service.
• New Entities were made in Rating-data-Service.
• PostMapping methods were added for the above mentioned two services.
• Still hardcoded URL's are used from Movie-Catalog-Service but will be changed in future.

3. Microservice architecture with an embedded Database and eureka as service discovery

• The code will be in the eureka branch.

• New spring boot application called disovery-server is created whioh acts as the Eureka Server. All services are registered here.

• New Dependencies are added in the other 3 services to act as Eureka Clients and are assigned name in the application.properties files.

• Hardcoded URL's are updated with the service names.

• The registered services can be seen below:
  

• The output still remains the same:
  Catalog-1
  

  Catalog-2
  

4. Dockerized Microservice architecture with an embedded Database and eureka as service discovery

• The code will be in the docker branch.
• Yet to be implemented

For details now how everything has been implemented, refer the source code.

Running the App

Starting the Database

• Start the mongo database using the following commands:

  • Open a terminal and run mongod
  • Open another terminal and run mongo
    • You can run mongo related commands here

  Alternatively, open MongoDB Compass and start a new connection to the host at http://localhost:27017/

Starting the Microservices

There are multiple commands that are useful when working with gradle

• Open terminal in the root directory of each of the service
  • To build the project, use the following command:

    gradle build
  

  • To run the project, use the following command:

    gradle bootRun
  

Start the service-discovery(eureka) first and then all the microservices

Resources

• Java Brains Tutorial