profie

Spring config server is one of the very important module of spring cloud to basically externalize application configuration. In a microservice architecture, spring config server provides a central place where all the microservices can look for the application configuration. It has support for multiple applications and environments.

We will look into a sample spring server application supported by git as storage for the application config. Although we can use a different form of storage but then it will require some additional changes.

Navigate to spring https://start.spring.io/ and add config server to dependencies, provide the artifact details as per the screenshot below or choose one of your own and click on generate

This will download a zip to you local filesystem. Unzip the directory and import/open the project into your favorite IDE. I am using Intellij.

The imported project will look like below.

Take a look at the pom.xml, it will have dependency for spring cloud config server apart from the spring boot starter dependency. Also it will import spring cloud dependencies using the maven import pom.

<dependency>
 <groupId>org.springframework.cloud</groupId>
 <artifactId>spring-cloud-config-server</artifactId>
</dependency>

delete the application.properties file and create application.yml instead. Set the application name and set the server port to 8001 as below

spring:
  application:
    name: my-config-server

server:
  port: 8001

let us create a git repository on our local and then migrate it on to the github.

create a directory app-config and navigate into the directory on command line and fire command “git init”

create a file inside the app-config directory. lets say myapp.yml and add a property like below

app:
 name: my-first-app

Now add this file to the git repo using git add and then git commit as below

let us add reference to this repo in our spring boot application. To do this, just open the application.yml file use the spring.cloud.config.git.url to the repository we created like below

spring:
  application:
    name: my-config-server
  cloud:
    config:
      server:
        git:
          uri: file://c://Users/Amey/git/app-config

Now to initialize our spring boot application as config server, we have to add the annotation @EnableConfigServer to our main class like below

@SpringBootApplication
@EnableConfigServer
public class MyConfigServerApplication {
	public static void main(String[] args) {
		SpringApplication.run(MyConfigServerApplication.class, args);
	}

}

Now we are ready to run the spring config server application. Right click on the class and run the application.

Now on the browser, navigate to the url “http://localhost:8001/my-first-app/master” to see spring config server responding as below

Here the spring has assumed the default profile as master or assumed that the branch is the default profile.

Now lets add another file to the git repo with name “my-first-app-dev.yml” and add the following property to the config

app:
 name: my-first-app-dev

lets go back to the browser and now instead of master lets use dev as the profile in the url and check what the server responds with ( “ http://localhost:8001/my-first-app/dev“) .

Now our spring config server has done the magic trick. It has returned us the dev profile for our application. if you see the app.name is now my-first-app-dev and also we did not restart the server. Spring has picked up the change and responded with new profile we just added.

In the next blog, we will see various other configurations that we can use with spring config server.