Shopping Application

This an implementation of real-world, industry-approved practices of several important concepts.

It consists of some backend microservices with infrastructure which function in a unified way.

These microservices are developed using:

• Spring Boot/Cloud/Security for foundations;
• MySQL/PostgreSQL/MongoDB for storage;
• Netflix Eureka for service discovery;
• Spring Kafka for message queue;
• Zipkin for distributed span tracing;
• Keycloak for user(s) authorization;
• Prometheus for scraping live metrics;
• Grafana for statistics visualization.

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Requirements

The stable releases of the following technologies are used:

Technology	Version	Technology	Version
JDK	17+	Spring Boot	3.0+
Spring Cloud	2022+	Spring Kafka	3.0+
Lombok	1.18+	MySQL	8.0+
MongoDB	5.0+	PostgreSQL	15.3+
Netflix Eureka	4.0+	Keycloak	21.0+
Prometheus	2.40+	Grafana	9.0+
Maven	3.8+	Docker	20+

P.S. For production purposes, only Docker is sufficient.

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Development

For development purposes (without Prometheues and Grafana), follow as below:

Preparing Infrastructure

1. Deploy the Mongo database for the product-service with this Docker command:

   docker run --detach --name dev-mongo --publish 27017:27017 mongo:5.0.18-focal
   

2. Deploy the MySQL database for the order/inventory-Services with this Docker command:

   docker run --detach --name dev-mysql --publish 3306:3306 \
              --env MYSQL_ROOT_PASSWORD=dev-root mysql:8-oracle
   

3. Enter mysqlsh in the terminal and execute these commands:

   \connect root@localhost:3306
   \sql
   create schema `order-data`;
   create schema `inventory-data`;
   \quit
   

4. Deploy the Keycloak server for authorization with this Docker command:

   docker run --detach --name dev-keycloak --publish 8181:8080 \
              --env KEYCLOAK_ADMIN=admin --env KEYCLOAK_ADMIN_PASSWORD=pass \
                quay.io/keycloak/keycloak:21.1 start-dev
   

5. Deploy the Zipkin server for tracing with this Docker command:

   docker run --detach --name dev-zipkin \
              --publish 9411:9411 openzipkin/zipkin
   

6. Start the Kafka service for communication with this Docker command:

   docker-compose --detach start kafka-broker
   

Booting Microservices

1. Build the Maven application with this Maven command:

   mvn clean install

2. Execute each Maven module with this Maven command:

   mvn spring-boot:run

Utilizing Application

1. Go to the Keycloak server URL: http://localhost:8181 and login with: [admin:pass]

2. Open the shopping-microservices-realm from the list of available Realms.

3. Generate new Access Token through the Postman client with these settings:

   Authorization -> Type = OAuth 2.0
   
   Configure New Token -> Token Name = keycloak-token
                          Grant Type = Client Credentials
                          Access Token URL = Value of "token_endpoint" from Realm Settings -> OpenID Config.
                          Client ID = spring-cloud-client
                          Client Secret = Value from Clients -> "spring-cloud-client" -> Credentials
                          Scope = openid offline_access
   

4. Test these URLs with this Access Token to consume the APIs:

   http://localhost:8080/api/product
   http://localhost:8080/api/order
   

Monitoring Application

1. Connect to the Mongo DB at the following URI:

   mongodb://localhost:27017/product-data
   

2. Connect to the MySQL DBs at the following URI:

   jdbc:mysql://localhost:3306/order-data
   jdbc:mysql://localhost:3306/inventory-data
   

   ... with these credentials: [root:dev-root]

3. Check the instances available at the Eureka server URL:

   http://localhost:8761 or http://localhost:8080/eureka/web

4. Check the distributed tracing at the Zipkin server URL:

   http://localhost:9411/zipkin

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Production

For production purposes (with Prometheues and Grafana), follow as below:

Running Application

1. Create the Docker containers with this Maven command:

   mvn clean install jib:build

2. Start the entire application with this Docker command:

   docker-compose --detach up

Utilizing Application

1. Go to the Keycloak server URL: http://localhost:8181 and login with: [admin:pass]

2. Open the shopping-microservices-realm from the list of available Realms.

3. Generate new Access Token through the Postman client with these settings:

   Authorization -> Type = OAuth 2.0
   
   Configure New Token -> Token Name = keycloak-token
                          Grant Type = Client Credentials
                          Access Token URL = Value of "token_endpoint" from Realm Settings -> OpenID Config.
                          (Replace `localhost` with `keycloak-auth`, i.e. the name of its Container service)
                          (Include `127.0.0.1 keycloak-auth` inside `C:\Windows\System32\drivers\etc\hosts`)
                          Client ID = spring-cloud-client
                          Client Secret = Value from Clients -> "spring-cloud-client" -> Credentials
                          Scope = openid offline_access
   

4. Test these URLs with this Access Token to consume the APIs:

   http://localhost:8080/api/product
   http://localhost:8080/api/order
   

Monitoring Application

1. Connect to the Mongo DB at the following URI:

   mongodb://localhost:27017/product-data
   

2. Connect to the PostgreSQL DBs at the following URI:

   jdbc:postgresql://localhost:3306/order-data
   jdbc:postgresql://localhost:3306/inventory-data
   

   ... with these credentials: [user:pass]

3. Check the instances available at the Eureka server URL:

   http://localhost:8761 or http://localhost:8080/eureka/web

4. Check the distributed tracing at the Zipkin server URL:

   http://localhost:9411/zipkin

5. Check the application metrics at the Prometheus server URL:

   http://localhost:9090

6. Visualize the application activity at the Grafana server URL:

   http://localhost:3000

   ... with these credentials: [admin:pass]

7. Add Prometheus as a Data Source for Grafana.

8. Import the grafana-dashboard.json file into the Dashboards.

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Thank you for using it!

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