I posted an article in regards to a single-page application(UI), but in this post, I’m going to introduce how to build microservice architecture for the J2EE application with Spring framework and open-source SSO framework Keycloak. This post will cover the following aspects:

• Keycloak setup
• Eureka service registration and discovery
• Spring Cloud API gateway
• Spring Security (OAuth2 login) and the integration with Keycloak
• Microservices

The code is available in my Github and please check the docker-compose.yml at first so that you can read the rest of the post easier. One thing I need to mention here is you need to replace the IP address of the keycloak server URL with your own before running the docker containers.

version: '3.4'
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services:
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  api-gateway:
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    build:
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      context: ./api-gateway
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    ports:
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      - "8080:8080"
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    restart: on-failure
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    environment:
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      #overriding spring application.properties
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      - eureka.client.serviceUrl.defaultZone=http://eureka-server:9091/eureka/
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      - keycloak-client.server-url=http://10.0.0.17:18080/auth ## use host name or ip of the host machine
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    depends_on:
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      - eureka-server
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  eureka-server:
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    build:
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      context: ./eureka-server
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    ports:
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      - "9091:9091"
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    restart: on-failure
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  microservice-consumer:
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    build:
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      context: ./microservice-consumer
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    ports:
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      - "9080:9080"
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    restart: on-failure
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    environment:
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      #overriding spring application.properties
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      - eureka.client.serviceUrl.defaultZone=http://eureka-server:9091/eureka/
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      - keycloak-client.server-url=http://10.0.0.17:18080/auth ## use host name or ip of the host machine
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    depends_on:
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      - eureka-server
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  microservice-producer:
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    build:
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      context: ./microservice-producer
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    ports:
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      - "9081:9081"
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    restart: on-failure
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    environment:
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      #overriding spring application.properties
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      - eureka.client.serviceUrl.defaultZone=http://eureka-server:9091/eureka/
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      - keycloak-client.server-url=http://10.0.0.17:18080/auth ## use host name or ip of the host machine
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    depends_on:
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      - eureka-server
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  keycloak:
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    image: jboss/keycloak:11.0.0
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      volumes:
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      - ./keycloak-server/realm-export.json:/tmp/keycloak/config/realm-export.json
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    environment:
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        KEYCLOAK_USER: admin
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        KEYCLOAK_PASSWORD: admin
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        KEYCLOAK_IMPORT: /tmp/keycloak/config/realm-export.json
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        DB_VENDOR: POSTGRES
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        DB_ADDR: postgres
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        DB_DATABASE: keycloak
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        DB_USER: keycloak
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        DB_SCHEMA: public
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        DB_PASSWORD: password
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    ports:
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      - "18080:18080"
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    command:
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      - "-b"
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      - "0.0.0.0"
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      - "-Djboss.socket.binding.port-offset=10000"
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    restart: on-failure
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    depends_on:
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      - postgres
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  postgres:
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      image: postgres
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      volumes:
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        - postgres_data:/var/lib/postgresql/data
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      environment:
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        POSTGRES_DB: keycloak
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        POSTGRES_USER: keycloak
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        POSTGRES_PASSWORD: password
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volumes:
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    postgres_data:
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      name: keycloak_postgres_data
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      driver: local

#spring boot #microservice #spring cloud #keycloak #eureka server #spring cloud gateway #spring secuirty 5 #sso authentication #java microservice #jwt token