Abstract

• This repo represents a basic currency conversion cloud native-app which convert currency from given country code to targeted country code.
• I am using the following stack for this cloud native app.
  • Microservice Architecture with API-GATEWAY along with Discovery Server
  • Spring Security with OAuth2 and KeyCloak Server
  • ELK Stack
  • Distributed Tracing
• Following are the Tools and technologies which I am using:
  • Java 17
  • Spring Boot 2.6.4
  • Spring Cloud 2021.0.1 (Security, Config Server, Service Discovery and Distributed Tracing)
  • KeyCloak Server (Authorization Server) 16.1.1
  • Zipkin Version 2.23.16 (Distribute Tracing)
  • Rabbit MQ Version 3.9.13-management(Message Broker)
  • ELK Stack Version 7.17.1

Requirements

• Add the line 127.0.0.1 auth-server in the last of your hosts file.
  • For Linux/Unix based system, its location is at: /etc/hosts
  • For Windows, its location is at: c:\Windows\System32\Drivers\etc\hosts
• Docker 20.xx.x or later

How to Run: Watch Video

• git clone https://github.com/UbaidurRehman1/Cloud-Native-App-Spring-Boot
• cd Cloud-Native-App-Spring-Boot/envcn
• ./run-multi-stage.sh (it will run all tools which our services needs such as keycloak server, discovery server, databases, zipkin, rabbitmq and elk-stack)
• cd ..
• ./run-multi-stage.sh (it will up the microservices)
• Access Web Client UI
• Access Swagger Client UI
  • To authorize the requests in Swagger, please follow this

Run in Kubernetes

About

• This App basically converts a currency from given country code to targeted country code by following the cloud native approach.
• api-gateway provides a gateway for end clients (web browsers, mobiles) to interact the resource servers (micro-services)
• An Actor (React Client, React Native Client) can interact with the micro-services through the api-gateway
• 
• In above diagram, We can see:
  • An End Client can access the resource servers through the api-gatewy
  • There are five resource servers:
    1. currency-conversion service abstract the functions of getting exchange rate from currency-exchange service and converting this exchange rate by the help of math service.
    2. currency-exchange service return the exchange rate between two currencies.
    3. math service convert the currency to another currency using the exchange rate.
    4. country service return all countries
    5. user service is related about user information
  • An api-gateway exposes its URLs to Clients
  • Keycloak Server (For OAuth2 Authentication and Authorization)
  • Discovery Server (For services discovery)
  • Distributed Tracing Stack, for request tracing in micro-service architecture
  • ELK Stack, for Centralized Logging
  • Config Server to get distributed app configurations (hosted in github/public-repo) for each micro-service

Swagger UI

Auth Flow

Distributed Tracing

Kibana Dashboard (For Centralized Logging)

• Create Index for logging
• Go here to view centralized logs

Micro-Services

• API Composer
• Currency Exchange Service
• Currency Conversion Service
• Country Service
• User Service
• API Gateway

Servers

• AUTH SERVER
• NAMING SERVER
• CONFIG SERVER
• ZIPKIN SERVER
• RABBIT MQ SERVER Username & Password: guest

Config Repo

• Public Config Repo

Note

• You can read about each micro-service by going inside each folder
• To get More info about this repo