Spring Cloud 簡單入門教程 之 Sleuth （六）

在分佈式架構中，需要對分佈式服務進行治理，也就是要記錄到服務的調用和被調用的具體信息，比如調用時間，響應時間等等。稱爲服務的調用鏈。記錄每個服務的調用鏈–分佈式服務服務跟蹤。
Spring Cloud Sleuth爲Spring Cloud實現分佈式跟蹤解決方案。
Span：工作的基本單位 例如，發送RPC是一個新的跨度，以及向RPC發送響應。Span由跨度的唯一64位ID標識，跨度是其中一部分的跟蹤的另一個64位ID。跨度還具有其他數據，例如描述，時間戳記事件，鍵值註釋（標籤），導致它們的跨度的ID以及進程ID（通常是IP地址）。
跨距開始和停止，他們跟蹤他們的時間信息。創建跨度後，必須在將來的某個時刻停止。
啓動跟蹤的初始範圍稱爲root span。該跨度的跨度id的值等於跟蹤ID。
跟蹤：一組spans形成樹狀結構。例如，如果您正在運行分佈式大數據存儲，則可能會由put請求形成跟蹤。
註釋： 用於及時記錄事件的存在。用於定義請求的開始和停止的一些核心註釋是：
cs - 客戶端發送 - 客戶端已經發出請求。此註釋描繪了跨度的開始。
sr - 服務器接收 - 服務器端得到請求，並將開始處理它。如果從此時間戳中減去cs時間戳，則會收到網絡延遲。
ss - 服務器發送 - 在完成請求處理後（響應發送回客戶端時）註釋。如果從此時間戳中減去sr時間戳，則會收到服務器端處理請求所需的時間。
cr - 客戶端接收 - 表示跨度的結束。客戶端已成功接收到服務器端的響應。如果從此時間戳中減去cs時間戳，則會收到客戶端從服務器接收響應所需的整個時間。
可視化Span和Trace將與Zipkin註釋一起查看系統：

構建項目server-zipkin，添加依賴

<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>

啓動類上加上註解@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
構建ZipkinClient項目，添加依賴

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

	}

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

構建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 "這裏是Cilent2的hi接口";
	}

	@RequestMapping("/sayHello")
	public String info(){
		LOG.log(Level.INFO, "調用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();
	}
}

瀏覽器訪問http://localhost:9411/

瀏覽器訪問http://localhost:8989/sayHello

http://localhost:9411/dependency


可以看到服務之間相互調用的數據。
注意：接口名稱不能使用info，info應該已經被內部使用了，調用info返回空數據。

各種IT書籍書目及下載鏈接
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