Spring Cloud Configuration Server is a centralized application that manages all the application related configuration properties. In this blog, you will learn in detail about how to create Spring Cloud Configuration server.

Creating Spring Cloud Configuration Server

First, download the Spring Boot project from the Spring Initializer page and choose the Spring Cloud Config Server dependency. Observe the screenshot given below −

Now, add the Spring Cloud Config server dependency in your build configuration file as explained below −
Maven users can add the below dependency into the pom.xml file.
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-config-server</artifactId>
</dependency>
Gradle users can add the below dependency in your build.gradle file.
compile(‘org.springframework.cloud:spring-cloud-config-server’)
Now, add the @EnableConfigServer annotation in your main Spring Boot application class file. The @EnableConfigServer annotation makes your Spring Boot application act as a Configuration Server.
The main Spring Boot application class file is given below −
package com.tecklearn.configserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.config.server.EnableConfigServer;

@SpringBootApplication
@EnableConfigServer
public class ConfigserverApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigserverApplication.class, args);
}
}
Now, add the below configuration to your properties file and replace the application.properties file into bootstrap.properties file. Observe the code given below −
server.port = 8888
spring.cloud.config.server.native.searchLocations=file:///C:/configprop/
SPRING_PROFILES_ACTIVE=native
Configuration Server runs on the Tomcat port 8888 and application configuration properties are loaded from native search locations.
Now, in file:///C:/configprop/, place your client application – application.properties file. For example, your client application name is config-client, then rename your application.properties file as config-client.properties and place the properties file on the path file:///C:/configprop/.
The code for config-client properties file is given below −
welcome.message = Welcome to Spring cloud config server
The complete build configuration file is given below −
Maven users can use pom.xml given below −

<?xml version = "1.0" encoding = "UTF-8"?>
<project xmlns = "http://maven.apache.org/POM/4.0.0" 
xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation = "http://maven.apache.org/POM/4.0.0 
http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>
<groupId>com.tecklearn</groupId>
<artifactId>configserver</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>configserver</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Edgware.RELEASE</spring-cloud.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-config-server</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

</project>

Gradle users can use the build.gradle file given below −

<scope>import</scope>
</dependency>
</dependencies>
buildscript {
ext {
springBootVersion = '1.5.9.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'

group = 'com.tecklearn'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
mavenCentral()
}
ext {
springCloudVersion = 'Edgware.RELEASE'
}
dependencies {
compile('org.springframework.cloud:spring-cloud-config-server')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
}
}

Now, create an executable JAR file, and run the Spring Boot application by using the following Maven or Gradle commands −
For Maven, use the command given below −
mvn clean install
After “BUILD SUCCESS”, you can find the JAR file under the target directory.
For Gradle, use the command given below −
gradle clean build
After “BUILD SUCCESSFUL”, you can find the JAR file under the build/libs directory.
Run the JAR file by using the following command −
java –jar <JARFILE>
Now, the application has started on the Tomcat port 8888 as shown here −

Now hit the URL http://localhost:8888/config-client/default/master on your web browser and you can see your config-client application configuration properties as shown here.

Spring Boot – Cloud Configuration Client

Some applications may need configuration properties that may need a change and developers may need to take them down or restart the application to perform this. However, this might be lead to downtime in production and the need of restarting the application. Spring Cloud Configuration Server lets developers to load the new configuration properties without restarting the application and without any downtime.

Working with Spring Cloud Configuration Server

First, download the Spring Boot project from https://start.spring.io/ and choose the Spring Cloud Config Client dependency. Now, add the Spring Cloud Starter Config dependency in your build configuration file.
Maven users can add the following dependency into the pom.xml file.
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
Gradle users can add the following dependency into the build.gradle file.
compile(‘org.springframework.cloud:spring-cloud-starter-config’)
Now, you need to add the @RefreshScope annotation to your main Spring Boot application. The @RefreshScope annotation is used to load the configuration properties value from the Config server.
package com.example.configclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.context.config.annotation.RefreshScope;

@SpringBootApplication
@RefreshScope
public class ConfigclientApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigclientApplication.class, args);
}
}
Now, add the config server URL in your application.properties file and provide your application name.
Note − http://localhost:8888 config server should be run before starting the config client application.
spring.application.name = config-client
spring.cloud.config.uri = http://localhost:8888
The code for writing a simple REST Endpoint to read the welcome message from the configuration server is given below −

package com.example.configclient;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RefreshScope
@RestController
public class ConfigclientApplication {
@Value("${welcome.message}")
String welcomeText;

public static void main(String[] args) {
SpringApplication.run(ConfigclientApplication.class, args);
}
@RequestMapping(value = "/")
public String welcomeText() {
return welcomeText;
}
}

You can create an executable JAR file, and run the Spring Boot application by using the following Maven or Gradle commands −
For Maven, you can use the command shown below −
mvn clean install
After “BUILD SUCCESS”, you can find the JAR file under the target directory.
For Gradle, you can use the command shown below −
gradle clean build
After “BUILD SUCCESSFUL”, you can find the JAR file under the build/libs directory.
Now, run the JAR file by using the command shown here:
java –jar <JARFILE>
Now, the application has started on the Tomcat port 8080 as shown here −

You can see the log in console window; config-client application is fetching the configuration from the https://localhost:8888
2017-12-08 12:41:57.682 INFO 1104 — [
main] c.c.c.ConfigServicePropertySourceLocator :
Fetching config from server at: http://localhost:8888
Now hit the URL, http://localhost:8080/ welcome message is loaded from the Configuration server.

Now, go and change the property value on the Configuration server and hit the actuator Endpoint POST URL http://localhost:8080/refresh and see the new configuration property value in the URL http://localhost:8080/
So, this brings us to the end of blog. This Tecklearn ‘How to Create Spring Cloud Configuration Server’ blog helps you with commonly asked questions if you are looking out for a job in Java Programming. If you wish to learn Spring Boot and build a career Java Programming domain, then check out our interactive, Java and JEE Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

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