Spring Cloud 简单入门教程 之 Sleuth （六）

在分布式架构中，需要对分布式服务进行治理，也就是要记录到服务的调用和被调用的具体信息，比如调用时间，响应时间等等。称为服务的调用链。记录每个服务的调用链–分布式服务服务跟踪。
Spring Cloud Sleuth为Spring Cloud实现分布式跟踪解决方案。
Span：工作的基本单位 例如，发送RPC是一个新的跨度，以及向RPC发送响应。Span由跨度的唯一64位ID标识，跨度是其中一部分的跟踪的另一个64位ID。跨度还具有其他数据，例如描述，时间戳记事件，键值注释（标签），导致它们的跨度的ID以及进程ID（通常是IP地址）。
跨距开始和停止，他们跟踪他们的时间信息。创建跨度后，必须在将来的某个时刻停止。
启动跟踪的初始范围称为root span。该跨度的跨度id的值等于跟踪ID。
跟踪：一组spans形成树状结构。例如，如果您正在运行分布式大数据存储，则可能会由put请求形成跟踪。
注释： 用于及时记录事件的存在。用于定义请求的开始和停止的一些核心注释是：
cs - 客户端发送 - 客户端已经发出请求。此注释描绘了跨度的开始。
sr - 服务器接收 - 服务器端得到请求，并将开始处理它。如果从此时间戳中减去cs时间戳，则会收到网络延迟。
ss - 服务器发送 - 在完成请求处理后（响应发送回客户端时）注释。如果从此时间戳中减去sr时间戳，则会收到服务器端处理请求所需的时间。
cr - 客户端接收 - 表示跨度的结束。客户端已成功接收到服务器端的响应。如果从此时间戳中减去cs时间戳，则会收到客户端从服务器接收响应所需的整个时间。
可视化Span和Trace将与Zipkin注释一起查看系统：

构建项目server-zipkin，添加依赖

<dependency>
	<groupId>io.zipkin.java</groupId>
	<artifactId>zipkin-server</artifactId>
</dependency>
<dependency>
	<groupId>io.zipkin.java</groupId>
	<artifactId>zipkin-autoconfigure-ui</artifactId>
</dependency>
<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-zipkin</artifactId>
</dependency>
完整pom文件
<?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.heyuanjun.server-zipkin</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>1.5.8.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>Camden.SR7</spring-cloud.version>
	</properties>

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

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

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

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

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

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

	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>

		<repository>
			<id>repository.springframework.maven.snapshot</id>
			<name>Spring Framework Maven Snapshot Repository</name>
			<url>http://repo.spring.io/snapshot/</url>
		</repository>
	</repositories>
</project>

启动类上加上注解@EnableZipkinServer，

/**
 * @author heyuanjun
 */
@SpringBootApplication
@EnableZipkinServer
public class ServerZipkinApplication {

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

配置文件作配置
server.port=9411
构建ZipkinClient项目，添加依赖

org.springframework.cloud
spring-cloud-starter-zipkin

完整pom文件

<?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.heyuanjun.zipkin-client</groupId>
	<artifactId>zipkin-client</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

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

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.8.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>Camden.SR7</spring-cloud.version>
	</properties>

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

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

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

	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>

		<repository>
			<id>repository.springframework.maven.snapshot</id>
			<name>Spring Framework Maven Snapshot Repository</name>
			<url>http://repo.spring.io/snapshot/</url>
		</repository>
	</repositories>
</project>

配置文件作如下配置
server.port=8999
spring.zipkin.base-url=http://localhost:9411
spring.application.name=service-sayhi
接口暴露

package com.heyuanjun.zipkinclient.zipkinclient;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

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

/**
 * @author DELL
 */
@SpringBootApplication
@RestController
public class ZipkinClientApplication {

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

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


	@Autowired
	private RestTemplate restTemplate;

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

	@RequestMapping("/sayHello")
	public String callHome(){
		LOG.log(Level.INFO, "调用zipClient2的sayHello");
		return restTemplate.getForObject("http://127.0.0.1:8989/hi", String.class);
	}
	@RequestMapping("/hi")
	public String info(){
		LOG.log(Level.INFO, "调用zipClient");
		return "这里是 zipClint1 的info接口";

	}

	@Bean
	public AlwaysSampler defaultSampler(){
		return new AlwaysSampler();
	}
}

构建zipclient2，pom文件：

<?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.heyuanjun.zipclient2</groupId>
	<artifactId>zipclient2</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>zipclient2</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.8.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>Camden.SR7</spring-cloud.version>
	</properties>

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

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

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

	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>

		<repository>
			<id>repository.springframework.maven.snapshot</id>
			<name>Spring Framework Maven Snapshot Repository</name>
			<url>http://repo.spring.io/snapshot/</url>
		</repository>
	</repositories>
</project>

配置文件：
server.port=8989
spring.zipkin.base-url=http://localhost:9411
spring.application.name=service-sayhello
接口暴露

package com.heyuanjun.zipclient2.zipclient2;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
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;

/**
 * @author DELL
 */
@SpringBootApplication
@RestController
public class Zipclient2Application {

	public static void main(String[] args) {
		SpringApplication.run(Zipclient2Application.class, args);
	}

	private static final Logger LOG = Logger.getLogger(Zipclient2Application.class.getName());


	@RequestMapping("/hi")
	public String home(){
		LOG.log(Level.INFO, "hi is being called");
		return "这里是Cilent2的hi接口";
	}

	@RequestMapping("/sayHello")
	public String info(){
		LOG.log(Level.INFO, "调用zipClient的info");
		return restTemplate.getForObject("http://127.0.0.1:8999/hi",String.class);
	}

	@Autowired
	private RestTemplate restTemplate;

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

	@Bean
	public AlwaysSampler defaultSampler(){
		return new AlwaysSampler();
	}
}

浏览器访问http://localhost:9411/

浏览器访问http://localhost:8989/sayHello

http://localhost:9411/dependency


可以看到服务之间相互调用的数据。
注意：接口名称不能使用info，info应该已经被内部使用了，调用info返回空数据。

各种IT书籍书目及下载链接
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