sleuth主要功能是在分布式系统中提供追踪解决方案，并且兼容支持了zipkin(提供了链路追踪的可视化功能)

zipkin原理：在服务调用的请求和响应中加入ID,表明上下游请求的关系。

利用这些信息，可以可视化地分析服务调用链路和服务间的依赖关系。

sleuth是对zipkin的封装，对应Span,Trace等信息的生成、接入http request,以及向Zipkin server发送采集信息等全部自动化完成。

目前主流的链路追踪组件有：google的Dapper,Twitter的zipkin和阿里的Eagleeye(鹰眼)。

1. 搭建zipkin服务器

1.1 创建springboot项目，引入相应的jar依赖(其他依赖参考前面的教材)

io.zipkin.java

zipkin-server

io.zipkin.java

zipkin-autoconfigure-ui

1.2 添加配置文件

server:

port: 8769

spring:

application:

name: zipkin-server

eureka:

client:

serviceUrl:

defaultZone: http://localhost:8761/eureka/ #注册服务器地址

management:

security:

enabled: false #关闭验证

info: #/info请求的显示信息

app:

name: ${spring.application.name}

version: 1.0.0

build:

artifactId: @project.artifactId@

version: @project.version@

1.3 在启动类中声明为zipkin服务器

@SpringBootApplication

@EnableDiscoveryClient

@EnableZipkinServer//zipkin服务器 默认使用http进行通信

public classZipkinServerApp {public static voidmain(String[] args) {

SpringApplication.run(ZipkinServerApp.class, args);

}

}

1.4 启动查看效果

2  分别在cloud-consumer-ribbon和cloud-consumer-feign中引入zipkin

2.1 引入zipkin依赖

org.springframework.cloud

spring-cloud-starter-zipkin

或

org.springframework.cloud

spring-cloud-sleuth-zipkin

org.springframework.cloud

spring-cloud-starter-sleuth

2.2 在配置文件中声明zipkin服务器的地址

spring:

zipkin:

base-url: http://localhost:8769

2.3 在项目中调用需要的服务

@RequestMapping("hello")

public String helloConsumer() {

//使用restTemplate调用消费服务提供者的SERVICE-HI的info服务

//String response=restTemplate.getForObject("http://cloud-consumer-feign/hi", String.class);

String response=hiService.sayHello()+" ribbon";

logger.info(response);

return response;

}

2.4 启动项目查看

有时候可能在zipkin服务器中看不到数据，那是因为默认sleuth收集信息的比率是0.1 ，针对于这个问题有两种解决方法：

a 在配置文件中配置 spring.sleuth.sampler.percentage=1

b 在代码中声明

//100%的来采集日志，和在配置文件中配置spring.sleuth.sampler.percentage=1是一样的

@BeanpublicAlwaysSampler defaultSampler(){return newAlwaysSampler();

}

但这样每个请求都会向zipkin server发送http请求，通信效率低，造成网络延迟。

而且所用的追踪信息都在内存中保存，重启zipkin server后信息丢失

针对以上的问题的解决方法：

a 采用socket或高效率的通信方式

b 采用异步方式发送信息数据

c 在客户端和zipkin之间增加缓存类的中间件，如redis,mq等，即时zipkin server重启过程中，客户端依然可以将数据发送成功

3 将http通信改为mq异步通信方式

3.1 修改zipkin server

3.1.1 将原来的依赖io.zipkin.java:zipkin-server换成spring-cloud-sleuth-zipkin-stream和spring-cloud-starter-stream-rabbit

org.springframework.cloud

spring-cloud-sleuth-zipkin-stream

org.springframework.cloud

spring-cloud-starter-stream-rabbit

io.zipkin.java

zipkin-autoconfigure-ui

3.1.2 在配置文件中配置ribbitmq地址

spring:

application:

name: zipkin-server

rabbitmq: #配置mq消息队列

host: localhost

port: 5672

username: guest

password: guest

3.1.3 在启动类中使用@EnableZipkinStreamServer替换@EnableZipkinServer

@SpringBootApplication

@EnableDiscoveryClient//@EnableZipkinServer//zipkin服务器 默认使用http进行通信

@EnableZipkinStreamServer //采用stream方式启动zipkin server ,也支持http通信 包含了@EnableZipkinServer,同时创建了rabbit-mq消息队列监听器

public classZipkinServerApp {public static voidmain(String[] args) {

SpringApplication.run(ZipkinServerApp.class, args);

}

}

3.2 配置客户端(这里只配置一个客户端，其他的客户端配置一样配置即可)

3.2.1 将原来的spring-cloud-starter-zipkin依赖，使用以下依赖进行替换

org.springframework.cloud

spring-cloud-sleuth-zipkin-stream

org.springframework.cloud

spring-cloud-starter-stream-rabbit

org.springframework.cloud

spring-cloud-starter-sleuth

3.2.2 在配置文件中加入ribbitmq的配置

spring:

rabbitmq: #配置mq消息队列

host: localhost

port: 5672

username: guest

password: guest

3.3 现在启动其他项目，不启动zipkin server，进行项目访问，会把追踪信息放入到ribbitmq中，当zipkin server启动后会直接冲zipkin server中获取信息

4 将追踪信息保存到数据库(只需修改zipkin server即可)

4.1 引入mysql数据库依赖

mysql

mysql-connector-java

org.springframework.boot

spring-boot-starter-jdbc

4.2 在配置文件msql连接

spring:

sleuth:

enabled: false #表示当前程序不使用sleuth

datasource: #配置msyql 连接

schema[0]: classpath:/zipkin.sql #数据库创建脚本，可以到官网下载

url: jdbc:mysql://localhost:3306/zipkin?autoReconnect=true&useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&useSSL=false

username: root

password: root

driver-class-name: com.mysql.jdbc.Driver

initialize: true

continue-on-error: true

zipkin:

storage:

type: mysql #mysql存储zipkin追踪信息

4.3 创建数据库和表

CREATE TABLE IF NOT EXISTSzipkin_spans (

`trace_id_high`BIGINT NOT NULL DEFAULT 0 COMMENT 'If non zero, this means the trace uses 128 bit traceIds instead of 64 bit',

`trace_id`BIGINT NOT NULL,

`id`BIGINT NOT NULL,

`name`VARCHAR(255) NOT NULL,

`parent_id`BIGINT,

`debug`BIT(1),

`start_ts`BIGINT COMMENT 'Span.timestamp(): epoch micros used for endTs query and to implement TTL',

`duration`BIGINT COMMENT 'Span.duration(): micros used for minDuration and maxDuration query') ENGINE=InnoDB ROW_FORMAT=COMPRESSED CHARACTER SET=utf8 COLLATE utf8_general_ci;ALTER TABLE zipkin_spans ADD UNIQUE KEY(`trace_id_high`, `trace_id`, `id`) COMMENT 'ignore insert on duplicate';ALTER TABLE zipkin_spans ADD INDEX(`trace_id_high`, `trace_id`, `id`) COMMENT 'for joining with zipkin_annotations';ALTER TABLE zipkin_spans ADD INDEX(`trace_id_high`, `trace_id`) COMMENT 'for getTracesByIds';ALTER TABLE zipkin_spans ADD INDEX(`name`) COMMENT 'for getTraces and getSpanNames';ALTER TABLE zipkin_spans ADD INDEX(`start_ts`) COMMENT 'for getTraces ordering and range';CREATE TABLE IF NOT EXISTSzipkin_annotations (

`trace_id_high`BIGINT NOT NULL DEFAULT 0 COMMENT 'If non zero, this means the trace uses 128 bit traceIds instead of 64 bit',

`trace_id`BIGINT NOT NULL COMMENT 'coincides with zipkin_spans.trace_id',

`span_id`BIGINT NOT NULL COMMENT 'coincides with zipkin_spans.id',

`a_key`VARCHAR(255) NOT NULL COMMENT 'BinaryAnnotation.key or Annotation.value if type == -1',

`a_value` BLOB COMMENT'BinaryAnnotation.value(), which must be smaller than 64KB',

`a_type`INT NOT NULL COMMENT 'BinaryAnnotation.type() or -1 if Annotation',

`a_timestamp`BIGINT COMMENT 'Used to implement TTL; Annotation.timestamp or zipkin_spans.timestamp',

`endpoint_ipv4`INT COMMENT 'Null when Binary/Annotation.endpoint is null',

`endpoint_ipv6`BINARY(16) COMMENT 'Null when Binary/Annotation.endpoint is null, or no IPv6 address',

`endpoint_port`SMALLINT COMMENT 'Null when Binary/Annotation.endpoint is null',

`endpoint_service_name`VARCHAR(255) COMMENT 'Null when Binary/Annotation.endpoint is null') ENGINE=InnoDB ROW_FORMAT=COMPRESSED CHARACTER SET=utf8 COLLATE utf8_general_ci;ALTER TABLE zipkin_annotations ADD UNIQUE KEY(`trace_id_high`, `trace_id`, `span_id`, `a_key`, `a_timestamp`) COMMENT 'Ignore insert on duplicate';ALTER TABLE zipkin_annotations ADD INDEX(`trace_id_high`, `trace_id`, `span_id`) COMMENT 'for joining with zipkin_spans';ALTER TABLE zipkin_annotations ADD INDEX(`trace_id_high`, `trace_id`) COMMENT 'for getTraces/ByIds';ALTER TABLE zipkin_annotations ADD INDEX(`endpoint_service_name`) COMMENT 'for getTraces and getServiceNames';ALTER TABLE zipkin_annotations ADD INDEX(`a_type`) COMMENT 'for getTraces';ALTER TABLE zipkin_annotations ADD INDEX(`a_key`) COMMENT 'for getTraces';ALTER TABLE zipkin_annotations ADD INDEX(`trace_id`, `span_id`, `a_key`) COMMENT 'for dependencies job';CREATE TABLE IF NOT EXISTSzipkin_dependencies (

`day` DATE NOT NULL,

`parent`VARCHAR(255) NOT NULL,

`child`VARCHAR(255) NOT NULL,

`call_count`BIGINT) ENGINE=InnoDB ROW_FORMAT=COMPRESSED CHARACTER SET=utf8 COLLATE utf8_general_ci;ALTER TABLE zipkin_dependencies ADD UNIQUE KEY(`day`, `parent`, `child`);