Adding spring cloud eureka for discovery service

Author: Nasruddin

.idea/compiler.xml

@@ -113,3 +113,9 @@ services:
       interval: 5s
       timeout: 2s
       retries: 60
+
+  eureka:
+    build: ../spring-cloud/eureka-server
+    mem_limit: 512m
+    ports:
+      - "8761:8761"

.idea/encodings.xml

@@ -15,6 +15,7 @@
 	<description>Demo project for Spring Boot</description>
 	<properties>
 		<java.version>17</java.version>
+		<spring-cloud.version>2021.0.1</spring-cloud.version>
 	</properties>
 	<dependencies>
 		<dependency>
@@ -45,6 +46,11 @@
 			<artifactId>lombok</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
+		</dependency>
+
 
 		<!--Internal Dep-->
 		<dependency>
@@ -71,6 +77,18 @@
 		</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>

.idea/misc.xml

@@ -4,9 +4,11 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.cloud.client.loadbalancer.LoadBalanced;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ComponentScan;
 import org.springframework.web.client.RestTemplate;
+import org.springframework.web.reactive.function.client.WebClient;
 
 @SpringBootApplication
 @ComponentScan("io.javatab")
@@ -18,8 +20,9 @@ public static void main(String[] args) {
 	}
 
 	@Bean
-	RestTemplate restTemplate() {
-		return new RestTemplate();
+	@LoadBalanced
+	public WebClient.Builder loadBalancedWebClientBuilder() {
+		return WebClient.builder();
 	}
 
 }

docker/docker-compose.yml

@@ -12,64 +12,50 @@
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.stereotype.Component;
 import org.springframework.web.client.RestTemplate;
+import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.reactive.function.client.WebClientResponseException;
 import reactor.core.publisher.Mono;
 
+import static java.util.logging.Level.FINE;
+
 @Component
 public class CourseCompositeIntegration implements CourseService, StudentService, VoteService {
 
     private static final Logger LOG = LoggerFactory.getLogger(CourseCompositeIntegration.class);
 
-    private final RestTemplate restTemplate;
+    private WebClient webClient;
     private final ObjectMapper objectMapper;
 
-    private final String courseServiceUrl;
-    private final String studentServiceUrl;
-    private final String voteServiceUrl;
+    private static final String COURSE_SERVICE_URL = "http://course";
+    private static final String STUDENT_SERVICE_URL = "http://student";
+    private static final String VOTE_SERVICE_URL = "http://vote";
 
     public CourseCompositeIntegration(
-            RestTemplate restTemplate,
-            ObjectMapper objectMapper,
-            @Value("${app.course-service.host}")
-            String courseServiceHost,
-            @Value("${app.course-service.port}")
-            String courseServicePort,
-            @Value("${app.student-service.host}")
-            String studentServiceHost,
-            @Value("${app.student-service.port}")
-            String studentServicePort,
-            @Value("${app.vote-service.host}")
-            String voteServiceHost,
-            @Value("${app.vote-service.port}")
-            String voteServicePort) {
-        this.restTemplate = restTemplate;
+            WebClient.Builder webClientBuilder,
+            ObjectMapper objectMapper) {
+        this.webClient = webClientBuilder.build();
         this.objectMapper = objectMapper;
-        this.courseServiceUrl = "http://" + courseServiceHost + ":" + courseServicePort + "/course/";
-        this.studentServiceUrl = "http://" + studentServiceHost + ":" + studentServicePort + "/student/";
-        this.voteServiceUrl = "http://" + voteServiceHost + ":" + voteServicePort + "/vote/";
     }
 
 
     @Override
     public Mono<Course> getCourse(int courseId) {
         LOG.info("Fetching courses in Integration layer");
-        var url = this.courseServiceUrl + courseId;
-        var course = restTemplate.getForObject(url, Course.class);
-        return Mono.just(course);
+        var url = COURSE_SERVICE_URL + "/course/" + courseId;
+        return webClient.get().uri(url).retrieve().bodyToMono(Course.class).log(LOG.getName(), FINE);
     }
 
     @Override
     public Mono<Student> getStudent(String studentId) {
         LOG.info("Fetching students in Integration layer");
-        var url = this.studentServiceUrl + studentId;
-        var student = restTemplate.getForObject(url, Student.class);
-        return Mono.just(student);
+        var url = STUDENT_SERVICE_URL + "/student/" + studentId;
+        return webClient.get().uri(url).retrieve().bodyToMono(Student.class).log(LOG.getName(), FINE);
     }
 
     @Override
     public Mono<Vote> getVote(int courseId) {
-        LOG.info("Fetching voting details in Integration layer");
-        var url = this.voteServiceUrl + courseId;
-        var vote = restTemplate.getForObject(url, Vote.class);
-        return Mono.just(vote);
+        LOG.info("Fetching votes in Integration layer");
+        var url = VOTE_SERVICE_URL + "/vote/" + courseId;
+        return webClient.get().uri(url).retrieve().bodyToMono(Vote.class).log(LOG.getName(), FINE);
     }
 }

microservices/course-composite-service/pom.xml

@@ -1,5 +1,5 @@
 server.port: 8016
-
+spring.application.name: course-composite
 app:
   course-service:
     host: localhost
@@ -65,11 +65,24 @@ springdoc:
   packagesToScan: io.javatab.microservices.composite.course
   pathsToMatch: /**
 
+app.eureka-server: localhost
+
+eureka:
+  client:
+    serviceUrl:
+      defaultZone: http://${app.eureka-server}:8761/eureka/
+    initialInstanceInfoReplicationIntervalSeconds: 5
+    registryFetchIntervalSeconds: 5
+  instance:
+    leaseRenewalIntervalInSeconds: 5
+    leaseExpirationDurationInSeconds: 5
 ---
 spring.config.activate.on-profile: docker
 
 server.port: 8080
 
+eureka.client.serviceUrl.defaultZone: http://eureka:8761/eureka/
+
 app:
   course-service:
     host: course

microservices/course-composite-service/src/main/java/io/javatab/microservices/composite/course/CourseCompositeServiceApplication.java

@@ -3,11 +3,9 @@
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
 
-@SpringBootTest
-class CourseCompositeServiceApplicationTests {
+import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
 
-	@Test
-	void contextLoads() {
-	}
+@SpringBootTest(webEnvironment=RANDOM_PORT, properties = {"eureka.client.enabled=false"})
+class CourseCompositeServiceApplicationTests {
 
 }

microservices/course-composite-service/src/main/java/io/javatab/microservices/composite/course/service/CourseCompositeIntegration.java

@@ -16,6 +16,7 @@
 	<properties>
 		<java.version>17</java.version>
 		<testcontainers.version>1.16.2</testcontainers.version>
+		<spring-cloud.version>2021.0.1</spring-cloud.version>
 	</properties>
 	<dependencies>
 		<dependency>
@@ -30,7 +31,10 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-data-mongodb</artifactId>
 		</dependency>
-
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.mapstruct</groupId>
 			<artifactId>mapstruct</artifactId>
@@ -78,6 +82,13 @@
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
+			<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>