SpringCloud Alibaba (四):Dubbo RPC框架

Dubbo简介

Apache Dubbo |ˈdʌbəʊ| 是一款高性能、轻量级的开源Java RPC框架,它提供了三大核心能力:面向接口的远程方法调用,智能容错和负载均衡,以及服务自动注册和发现。致力于提升性能和透明化的RPC远程服务调用方案,以及SOA服务治理方案。html

节点 角色说明
Provider 暴露服务的服务提供方
Consumer 调用远程服务的服务消费方
Registry 服务注册与发现的注册中心
Monitor 统计服务的调用次数和调用时间的监控中心
Container 服务运行容器

功能特色:java

  • 面向接口代理的高性能RPC调用web

    提供高性能的基于代理的远程调用能力,服务以接口为粒度,为开发者屏蔽远程调用底层细节。算法

  • 智能负载均衡spring

    内置多种负载均衡策略,智能感知下游节点健康情况,显著减小调用延迟,提升系统吞吐量。apache

  • 服务自动注册与发现api

    支持多种注册中心服务,服务实例上下线实时感知。架构

  • 高度可扩展能力app

    遵循微内核+插件的设计原则,全部核心能力如Protocol、Transport、Serialization被设计为扩展点,平等对待内置实现和第三方实现。负载均衡

  • 运行期流量调度

    内置条件、脚本等路由策略,经过配置不一样的路由规则,轻松实现灰度发布,同机房优先等功能。

  • 可视化的服务治理与运维

    提供丰富服务治理、运维工具:随时查询服务元数据、服务健康状态及调用统计,实时下发路由策略、调整配置参数。

Spring Cloud 为何须要RPC

在Spring Cloud构建的微服务系统中,大多数的开发者使用都是官方提供的Feign组件来进行内部服务通讯,这种声明式的HTTP客户端使用起来很是的简洁、方便、优雅,可是有一点,在使用Feign消费服务的时候,相比较Dubbo这种RPC框架而言,性能堪忧。

虽然说在微服务架构中,会讲按照业务划分的微服务独立部署,而且运行在各自的进程中。微服务之间的通讯更加倾向于使用HTTP这种简答的通讯机制,大多数状况都会使用REST API。这种通讯方式很是的简洁高效,而且和开发平台、语言无关,可是一般状况下,HTTP并不会开启KeepAlive功能,即当前链接为短链接,短链接的缺点是每次请求都须要创建TCP链接,这使得其效率变的至关低下。

对外部提供REST API服务是一件很是好的事情,可是若是内部调用也是使用HTTP调用方式,就会显得显得性能低下,Spring Cloud默认使用的Feign组件进行内部服务调用就是使用的HTTP协议进行调用,这时,咱们若是内部服务使用RPC调用,对外使用REST API,将会是一个很是不错的选择,恰巧,Dubbo Spring Cloud给了咱们这种选择的实现方式。

 

SpringCloud Alibaba 整合 Dubbo

建立ApacheDubbo总工程, 在pom.xml添加统一依赖

<?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.gofy</groupId>
    <artifactId>ApacheDubbo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging><parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
    </parent><modules>
        <module>dubbo-provider</module>
        <module>dubbo-consumer</module>
    </modules><properties>
        <!-- Environment Settings -->
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-cloud.version>Greenwich.SR3</spring-cloud.version>
        <spring-cloud-alibaba.version>0.2.1.RELEASE</spring-cloud-alibaba.version>
        <dubbo.version>2.7.6</dubbo.version>
        <dubbo-spring.version>2.7.6</dubbo-spring.version>
        <dubbo-actuator.version>2.7.6</dubbo-actuator.version>
        <dubbo-kryo.version>2.7.6</dubbo-kryo.version>
        <dubbo-nacos.version>2.7.6</dubbo-nacos.version>
        <dubbo-nacos-config.version>2.1.0.RELEASE</dubbo-nacos-config.version>
        <spring-context-support.version>1.0.6</spring-context-support.version>
    </properties><dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency><!-- Apache Dubbo  -->
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo</artifactId>
                <version>${dubbo.version}</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.springframework</groupId>
                        <artifactId>spring</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>javax.servlet</groupId>
                        <artifactId>servlet-api</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>log4j</groupId>
                        <artifactId>log4j</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-spring-boot-actuator</artifactId>
                <version>${dubbo-actuator.version}</version>
            </dependency>
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-spring-boot-starter</artifactId>
                <version>${dubbo-spring.version}</version>
            </dependency>
            <!-- 使用kryo序列化/反序列化工具, 提升项目性能 -->
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-serialization-kryo</artifactId>
                <version>${dubbo-kryo.version}</version>
            </dependency><!-- Spring Cloud Alibaba -->
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>dubbo-registry-nacos</artifactId>
                <version>${dubbo-nacos.version}</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba.nacos</groupId>
                <artifactId>nacos-client</artifactId>
                <version>1.2.1</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
                <version>${dubbo-nacos-config.version}</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba.spring</groupId>
                <artifactId>spring-context-support</artifactId>
                <version>${spring-context-support.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement><build>
        <plugins>
            <!-- Compiler 插件, 设定 JDK 版本 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <showWarnings>true</showWarnings>
                </configuration>
            </plugin>
        </plugins><!-- 资源文件配置 -->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <excludes>
                    <exclude>**/*.java</exclude>
                </excludes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
    </build>
</project>

服务提供者

在Dubbo RPC框架中, 服务提供者的接口类和实现类应该分开为俩个模块, 因此咱们应该在服务提供者下建立两个子模块, 分别为 接口模块dubbo-provider-api实现模块dubbo-provider-service

在总工程 ApacheDubbo下建立dubbo-provider模块, 添加服务提供者的统一依赖

<?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>

    <parent>
        <artifactId>ApacheDubbo</artifactId>
        <groupId>com.gofy</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <groupId>com.gofy</groupId>
    <artifactId>dubbo-provider</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <modules>
        <module>dubbo-provider-api</module>
        <module>dubbo-provider-service</module>
    </modules>
</project>
  • dubbo-provider下建立dubbo-provider-api子模块, 并添加依赖

<?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>
    <parent>
        <artifactId>dubbo-provider</artifactId>
        <groupId>com.gofy</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent><groupId>com.gofy</groupId>
    <artifactId>dubbo-provider-api</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging></project>

建立接口类 EchoService

package com.gofy.dubbo.api;
​
public interface EchoService {
    String echo(String s);
}
  • dubbo-provider下建立dubbo-provider-service子模块, 并添加依赖

导入接口模块失败缘由: 通常是总工程的统一依赖出了问题, 能够查看本地maven仓库的中总工程导入的依赖的包有没有缺失文件. 我以前失败缘由就是 spring-cloud-dependencies 包出了问题, Greenwich.SR5版本下载一直缺失文件, 改成Greenwich.SR3就行了.

<?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>
    <parent>
        <artifactId>dubbo-provider</artifactId>
        <groupId>com.gofy</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <groupId>com.gofy</groupId>
    <artifactId>dubbo-provider-service</artifactId>
    <packaging>jar</packaging>

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

        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-serialization-kryo</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo-registry-nacos</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba.spring</groupId>
            <artifactId>spring-context-support</artifactId>
        </dependency>

        <!-- 导入接口模块 -->
        <dependency>
            <groupId>com.gofy</groupId>
            <artifactId>dubbo-provider-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.gofy.dubbo.ProviderApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

dubbo-provider-service的application.yml里添加配置

注:若是要在 SpringClou Alibaba+Dubbo 中使用nacos动态配置,操做与以前naocs动态配置的操做同样

spring:
  application:
    name: dubbo-provider
  main:
    allow-bean-definition-overriding: true # 解决bean重复定义,设置为true时,后定义的bean会覆盖以前定义的相同名称的bean

dubbo:
  scan:
    base-packages: com.gofy.dubbo.service # 实现类所在的包
  protocol:
    name: dubbo
    port: -1 # 端口为-1时,便是让dubbo自动分配端口
    serialization: kryo # 使用kryo序列化/反序列化工具
  registry:
    address: nacos://192.168.11.132:8848 #注册中心地址,格式为 注册中心组件名://注册中心访问地址

建立实现类 EchoServiceImpl

package com.gofy.dubbo.service;
​
import com.gofy.dubbo.api.EchoService;
import org.apache.dubbo.config.annotation.Service;
import org.springframework.beans.factory.annotation.Value;
​
@Service(version = "1.0.0") //服务版本号
public class EchoServiceImpl implements EchoService {
​
    @Override
    public String echo(String s) {
        return "Hello Dubbo "+s;
    }
}

建立启动类 ProviderApplication

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

服务消费者

在总工程 ApacheDubbo下建立服务消费者 dubbo-consumer, 并添加依赖

<?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>
    <parent>
        <artifactId>ApacheDubbo</artifactId>
        <groupId>com.gofy</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <groupId>com.gofy</groupId>
    <artifactId>dubbo-consumer</artifactId>
    <packaging>jar</packaging>

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

        <!-- Dubbo -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-serialization-kryo</artifactId>
        </dependency>
        
        <!-- Spring Cloud Alibaba -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo-registry-nacos</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.spring</groupId>
            <artifactId>spring-context-support</artifactId>
        </dependency>

        <!-- 导入接口模块 -->
        <dependency>
            <groupId>com.gofy</groupId>
            <artifactId>dubbo-provider-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.gofy.dubbo.ConsumerApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

dubbo-consumer的application.yml里添加配置

server:
  port: 8080
​
spring:
  application:
    name: dubbo-consumer
  main:
    allow-bean-definition-overriding: true
​
dubbo:
  scan:
    base-packages: com.gofy.dubbo.controller #controller类所在包
  protocol:
    name: dubbo
    port: -1
    serialization: kryo
  registry:
    address: nacos://192.168.11.132:8848
​
endpoints:
  dubbo:
    enabled: true #容许暴露dubbo分配的端点
​
management:
  health: #健康检查
    dubbo:
      status:
        defaults: memory
        extras: threadpool
  endpoints: #暴露全部web端点
    web:
      exposure:
        include: "*"

建立controller类 EchoController

package com.gofy.dubbo.controller;
​
import com.gofy.dubbo.api.EchoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
​
@RestController
public class EchoController {
​
    @Reference(version = "1.0.0") //经过服务的版本号注入
    EchoService echoService;
    
    @GetMapping("/echo/{s}")
    public String echo(@PathVariable("s")String s){
        return echoService.echo(s);
    }
}

建立启动类 ConsumerApplication

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

访问测试

访问nacos注册中心,查看已注册服务

访问 localhost:8080/echo/hi , 成功获取到服务提供者返回的信息

 

Dubbo负载均衡

当咱们对内使用Dubbo的RPC通讯,再也不使用RestTemplate或feign的 HTTP通讯时,咱们要怎么使用负载均衡呢?

在 Dubbo 中,也有负载均衡的概念和相应的实现。Dubbo 须要对服务消费者的调用请求进行分配,避免少数服务提供者负载过大。服务提供者负载过大,会致使部分请求超时。所以将负载均衡到每一个服务提供者上,是很是必要的。Dubbo 提供了4种负载均衡实现,分别是基于权重随机算法的 RandomLoadBalance、基于最少活跃调用数算法的 LeastActiveLoadBalance、基于 hash 一致性的 ConsistentHashLoadBalance,以及基于加权轮询算法的 RoundRobinLoadBalance。

源码分析

Dubbo负载均衡的源码在 org.apache.dubbo:dubbo下的org.apache.dubbo.rpc.cluster.loadbalance

经过源码能够发现4个负载均衡策略的实现类都继承了AbstractLoadBalance抽象类,而AbstractLoadBalance实现了LoadBalance接口。

再来看看LoadBalance接口,能够知道duboo是经过 loadbalance属性来适配负载均衡接口的实现类,且默认值为 random权重随机。

@SPI("random")
public interface LoadBalance {
    @Adaptive({"loadbalance"})
    <T> Invoker<T> select(List<Invoker<T>> invokers, URL url, Invocation invocation) throws RpcException;
}

因此,咱们只要在@Reference注解里添加 loadbalance属性,就能够选择dubbo的负载均衡策略了

loadbalance属性值为负载均衡实现类的 NAME属性,分别是:

random 、roundrobin 、leastactive 、consistenthash

@Reference(version = "1.0.0", loadbalance = "roundrobin")
EchoService echoService;

负载均衡策略实现类的详细源码分析,dubbo官方文档里讲解得很是好,就很少转述了



个人我的博客站

翻译 朗读 复制 正在查询,请稍候…… 重试 朗读 复制 复制 朗读 复制 via 谷歌翻译(国内)

翻译 朗读 复制 正在查询,请稍候…… 重试 朗读 复制 复制 朗读 复制 via 谷歌翻译(国内)

相关文章
相关标签/搜索