Spring Cloud Sleuth(服务跟踪) springboot案例

好的，下面是一个使用Spring Cloud Sleuth进行服务跟踪的Spring Boot案例：

1. 添加依赖

在pom.xml文件中添加以下依赖：

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-sleuth</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-zipkin</artifactId>
</dependency>

2. 添加配置

在application.yml文件中添加以下配置：

spring:
  application:
    name: sleuth-demo
  sleuth:
    sampler:
      probability: 1.0
  zipkin:
    base-url: http://localhost:9411

其中，sleuth.sampler.probability配置为1.0表示采样率为100%。

3. 编写代码

编写一个Controller，调用其他服务：

@RestController
public class MyController {

    private final RestTemplate restTemplate;

    public MyController(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }

    @GetMapping("/hello")
    public String hello() {
        String result = restTemplate.getForObject("http://localhost:8080/world", String.class);
        return "Hello " + result;
    }
}

4. 启动服务

启动服务后，访问http://localhost:8080/hello，可以看到控制台输出类似于以下日志：

2021-05-28 11:08:26.306  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] c.e.sleuthdemo.controller.MyController  : hello
2021-05-28 11:08:26.311  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] o.apache.http.client.HttpClient         : http://localhost:8080/world HTTP/1.1
2021-05-28 11:08:26.311  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] o.apache.http.client.HttpClient         : Content-Length: 0
2021-05-28 11:08:26.311  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] o.apache.http.client.HttpClient         : Host: localhost:8080
2021-05-28 11:08:26.316  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] o.apache.http.client.HttpClient         : HTTP/1.1 200 
2021-05-28 11:08:26.316  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] o.apache.http.client.HttpClient         : Content-Type: application/json
2021-05-28 11:08:26.316  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] o.apache.http.client.HttpClient         : Transfer-Encoding: chunked
2021-05-28 11:08:26.316  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] o.apache.http.client.HttpClient         : Date: Fri, 28 May 2021 03:08:26 GMT
2021-05-28 11:08:26.316  INFO [sleuth-demo,9c3a3f80e0516d7f,9c3a3f80e0516d7f,false] 14292 --- [nio-8080-exec-1] o.apache.http.client.HttpClient         : 

这里的日志中，sleuth-demo为当前服务名，9c3a3f80e0516d7f为当前请求的Trace ID，false表示当前请求没有被采样。

5. 查看服务跟踪

访问http://localhost:9411/zipkin/，可以看到服务跟踪页面。在搜索框中输入服务名（sleuth-demo），可以看到当前服务的请求链路和请求耗时等信息。