How can we use Spring Cloud Sleuth with spring MVC project? - spring

Question

I am trying to use spring cloud sleuth with spring web mvc project. We are sending the request from spring web mvc to another spring boot project. I need to have the traceID and spanId to display in the UI. How can we achieve this?
EDIT
POM.xml for the spring boot application. I am using the latest version of Spring Boot and added the dependency of spring cloud sleuth.
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.test</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Hoxton.SR1</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-sleuth</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</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>
Web MVC code: I am using spring rest template and calling the spring boot service from the spring web mvc application.
#Controller
public class HelloController {
#Autowired
RestTemplate restTemplate;
private Logger logger = Logger.getLogger(HelloController.class);
#GetMapping("/hello")
public String hello(Model model) {
logger.info("Hello from controller");
ResponseEntity<String> entity = restTemplate.getForEntity("http://localhost:8092/test", String.class);
String response = entity.getBody();
logger.info("Response from Service: "+ response);
model.addAttribute("name", "Test");
return "welcome";
}
}

Answer 1

In order to do that, you need to inject the Tracer bean and then if you call tracer.currentSpan().context().traceIdString() and tracer.currentSpan().context().spanIdString().