Microservices with Spring Cloud Netflix

Application assemles a sentence from words provided by word services.

Config server provides the location of the Eureka server and 'words' property for each word service.

1. Building

If Gradle is installed, use it to build: gradle build.

If Gradle is not installed, use the wrapper to build: gradlew build.

First build Eureka server and Config server.

To build word services, Config server must be running otherwise integration tests fail.

2. Running

Start the Config server. Start the Eureka server.

Start all of the word services and the sentence app (API gateway).

Since each service uses a separate port, they should be able to run side-by-side on the same computer.

Check the Eureka server running at http://localhost:8010. Ensure that all of the word services and the API gateway are eventually listed in the Application section.

Open http://localhost:8080 to see the completed sentence.

Refresh the sentence service URL and watch the sentence change.

3. Using multiple Eureka Servers

Edit your computer's /etc/hosts file. Add the following lines and save your work:

# START section for Microservices with Spring Course
127.0.0.1       eureka-primary
127.0.0.1       eureka-secondary
127.0.0.1       eureka-tertiary
# END section for Microservices with Spring Course

Start 3 Eureka servers:

java -jar -Dspring.profiles.active=primary eureka-server-1.0.0.jar
java -jar -Dspring.profiles.active=secondary eureka-server-1.0.0.jar
java -jar -Dspring.profiles.active=tertiary eureka-server-1.0.0.jar

4. Dynamic Configuration Changes

We want to change an app configuration without restarting the app.

With all servers and services running, update one of the words properties in config-data/application.yml, and push the change to the GitHub repository.

Then issue the following POST request to Config server:

curl -X POST http://localhost:8001/bus/refresh

Refresh the sentence service URL and watch the sentence change.

5. TODO list

• Enable security management for Config server

• Add API gateway for mobile clients

• WARN: spring-cloud-starter-eureka is deprecated as of Spring Cloud Netflix 1.4.0, please migrate to spring-cloud-starter-netflix-eureka

• WARN: spring-cloud-starter-eureka-server is deprecated as of Spring Cloud Netflix 1.4.0, please migrate to spring-cloud-starter-netflix-eureka-server