spring cloud 教学九（服务链路追踪(Spring Cloud Sleuth)(Finchley版本)）

一、简介

Spring Cloud Sleuth 主要功能就是在分布式系统中提供追踪解决方案，并且兼容支持了 zipkin，你只需要在pom文件中引入相应的依赖即可。

二、服务追踪分析

微服务架构上通过业务来划分服务的，通过REST调用，对外暴露的一个接口，可能需要很多个服务协同才能完成这个接口功能，如果链路上任何一个服务出现问题或者网络超时，都会形成导致接口调用失败。随着业务的不断扩张，服务之间互相调用会越来越复杂。

实战讲解

基本知识讲解完毕，下面我们来实战，本文的案例主要有三个工程组成:一个server-zipkin,它的主要作用使用ZipkinServer 的功能，收集调用数据，并展示；一个service-hi,对外暴露hi接口；一个service-miya,对外暴露miya接口；这两个service可以相互调用；并且只有调用了，server-zipkin才会收集数据的，这就是为什么叫服务追踪了。

构建server-zipkin

pom依赖

<?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.forezp</groupId>
	<artifactId>server-zipkin</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>server-zipkin</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.2.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>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>io.zipkin.java</groupId>
			<artifactId>zipkin-server</artifactId>
		</dependency>

		<dependency>
			<groupId>io.zipkin.java</groupId>
			<artifactId>zipkin-autoconfigure-ui</artifactId>
		</dependency>

	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>Camden.SR6</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>

在其配置文件application.yml指定zipkin server的端口

server.port=9411

启动上面的工程，打开浏览器访问：http://localhost:9411/，会出现以下界面：

创建service-hi

在其pom引入起步依赖spring-cloud-starter-zipkin，代码如下：

<?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.forezp</groupId>
	<artifactId>service-zipkin</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>service-hi</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>com.forezp</groupId>
		<artifactId>sc-f-chapter9</artifactId>
		<version>0.0.1-SNAPSHOT</version>
	</parent>



	<dependencies>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

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



	</dependencies>

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

</project>

在其配置文件application.yml指定zipkin server的地址，头通过配置“spring.zipkin.base-url”指定：

server.port=8988
spring.zipkin.base-url=http://localhost:9411
spring.application.name=service-hi

通过引入spring-cloud-starter-zipkin依赖和设置spring.zipkin.base-url就可以了。

对外暴露接口：

package com.forezp;

import brave.sampler.Sampler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import java.util.logging.Level;
import java.util.logging.Logger;

@SpringBootApplication
@RestController
public class ServiceHiApplication {

	public static void main(String[] args) {
		SpringApplication.run(ServiceHiApplication.class, args);
	}

	private static final Logger LOG = Logger.getLogger(ServiceHiApplication.class.getName());


	@Autowired
	private RestTemplate restTemplate;

	@Bean
	public RestTemplate getRestTemplate(){
		return new RestTemplate();
	}

	@RequestMapping("/hi")
	public String callHome(){
		LOG.log(Level.INFO, "calling trace service-hi  ");
		return restTemplate.getForObject("http://localhost:8989/miya", String.class);
	}
	@RequestMapping("/info")
	public String info(){
		LOG.log(Level.INFO, "calling trace service-hi ");

		return "i'm service-hi";

	}

	@Bean
	public Sampler defaultSampler() {
		return Sampler.ALWAYS_SAMPLE;
	}


}

创建service-miya

创建过程痛service-hi，引入相同的依赖，配置下spring.zipkin.base-url。

对外暴露接口：

package com.forezp;

import brave.sampler.Sampler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import java.util.logging.Level;
import java.util.logging.Logger;

@SpringBootApplication
@RestController
public class ServiceMiyaApplication {

	public static void main(String[] args) {
		SpringApplication.run(ServiceMiyaApplication.class, args);
	}

	private static final Logger LOG = Logger.getLogger(ServiceMiyaApplication.class.getName());


	@RequestMapping("/hi")
	public String home(){
		LOG.log(Level.INFO, "hi is being called");
		return "hi i'm miya!";
	}

	@RequestMapping("/miya")
	public String info(){
		LOG.log(Level.INFO, "info is being called");
		return restTemplate.getForObject("http://localhost:8988/info",String.class);
	}

	@Autowired
	private RestTemplate restTemplate;

	@Bean
	public RestTemplate getRestTemplate(){
		return new RestTemplate();
	}


	@Bean
	public Sampler defaultSampler() {
		return Sampler.ALWAYS_SAMPLE;
	}
}

启动工程，演示追踪

依次启动上面的工程

访问：http://localhost:8989/miya，http://localhost:8988/hi

再打开http://localhost:9411/的界面，点击Dependencies,可以发现服务的依赖关系：

点击find traces,可以看到具体服务相互调用的数据：

本文源码下载：

https://pan.baidu.com/s/1D2iBTf7fV2TBV7zu151hnA