spring-bootdockerdocker-composemicroservicesfabric8-maven-plugin

How do I keep the Eureka server url dynamic in the Eureka Client while using docker?


I am using the fabric8 docker-maven-plugin to build image for my Spring boot microservices.

<groupId>io.fabric8</groupId>
<artifactId>docker-maven-plugin</artifactId>

The problem is that while running the application in docker containers I have to specify the Eureka Server Container name to Eureka Client. But if I run it directly as a "Spring Boot APP" I have to use "Localhost:8761/Eureka". Is there a way to make it work both with/without docker something like given below ?

eureka:
  client:
    service-url:
      defaultZone: ${EUREKA_SERVER:http://localhost:8761/eureka}

I am not able to pass the value of "EUREKA_SERVER" from the fabrib8 plugin. I have tried the below code to pass the value but it does not work.

<docker.env.JAVA_OPTS>-DEUREKA_SERVER=http://discovery:8761/eureka</docker.env.JAVA_OPTS>

Solution

  • Spring can pickup Environment Variables. So if you add Environment Variables to the Docker Container that Spring Boot is running in, they will work. This avoids the need to provide a static URL up front.

    If you use Docker Compose, it could look like this:

    services:
      eureka:
        image: springcloud/eureka
        container_name: eureka
        ports:
          - "8761:8761"
        networks:
          - "discovery"
        environment:
          - EUREKA_INSTANCE_PREFERIPADDRESS=true
    
      spring:
        build:
          context: .
          dockerfile: ./src/main/docker/Dockerfile
        depends_on:
          - eureka
        container_name: spring
        ports:
         - "8080:8080"
        networks:
         - "discovery"
        environment:
          - EUREKA_SERVICE_URL=http://eureka:8761 // This overrides your Spring Property
          - EUREKA_INSTANCE_PREFER_IP_ADDRESS=true
          - LOGGING_FILE=/tmp/admin.log
    

    Note: Since Environment Variables are not YAML, you need to change the format a bit. https://docs.spring.io/spring-boot/docs/1.5.5.RELEASE/reference/html/boot-features-external-config.html#boot-features-external-config-relaxed-binding