微服务框架（二十）Dubbo Spring Boot 生产就绪特性

　　此系列文章将会描述Java框架Spring Boot、服务治理框架Dubbo、应用容器引擎Docker，及使用Spring Boot集成Dubbo、Mybatis等开源框架，其中穿插着Spring Boot中日志切面等技术的实现，然后通过gitlab-CI以持续集成为Docker镜像。
　　本文为Dubbo Spring Boot 生产就绪特性

本系列文章中所使用的框架版本为Spring Boot 2.0.3-RELEASE，Spring 5.0.7-RELEASE，Dubbo 2.6.2。

Dubbo埋点

dubbo-spring-boot-actuator提供生产就绪(Production-Ready)特性 (比如健康检查,OPS端点,及外部化配置)

详见Dubbo Spring Boot Production-Ready

Maven依赖

<dependency>
    <groupId>com.alibaba.boot</groupId>
    <artifactId>dubbo-spring-boot-actuator</artifactId>
    <version>${dubbo.springboot.version}</version>
</dependency>

最新版本为贡献给apache基金会后的依赖

<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo-spring-boot-actuator</artifactId>
    <version>2.7.0</version>
</dependency>

application配置

# dubbo endpoints
management.endpoint.dubbo.enabled = true
management.endpoint.dubbo-configs.enabled = true
management.endpoint.dubbo-properties.enabled = true
management.health.dubbo.status.defaults = memory
management.health.dubbo.status.extras = load,threadpool

注：需在Web或JMX暴露对应的端点，即添加对应的endpoints，如：

management.endpoints.web.exposure.include = dubbo,dubbo-configs,dubbo-properties

健康检查

dubbo-spring-boot-actuator支持标准的Spring Boot健康指示器作为生产就绪特性，它将聚合到Spring Boot的Health中，并在运行MVC (Spring Web MVC)和JMX (Java管理扩展)的HealthEndpoint上暴露

Web Health端点

您可以通过Web Client访问health endpoints，亦可独立通过management.server.port为访问端点设置端口号。获得JSON格式的响应，如下所示

{
  "status": "UP",
  "dubbo": {
    "status": "UP",
    "memory": {
      "source": "management.health.dubbo.status.defaults",
      "status": {
        "level": "OK",
        "message": "max:3641M,total:383M,used:92M,free:291M",
        "description": null
      }
    },
    "load": {
      "source": "management.health.dubbo.status.extras",
      "status": {
        "level": "OK",
        "message": "load:1.73583984375,cpu:8",
        "description": null
      }
    },
    "threadpool": {
      "source": "management.health.dubbo.status.extras",
      "status": {
        "level": "OK",
        "message": "Pool status:OK, max:200, core:200, largest:0, active:0, task:0, service port: 12345",
        "description": null
      }
    },
    "server": {
      "source": "[email protected]()",
      "status": {
        "level": "OK",
        "message": "/192.168.1.103:12345(clients:0)",
        "description": null
      }
    }
  }
  // ignore others
}

在上面的例子中，memory, load, threadpool,server是Dubbo的内置StatusCheckers。 Dubbo允许应用程序扩展StatusChecker的SPI。

在缺省配置中，memory 及 load将添加到Dubbo的HealthIndicator中，它可以被外部化配置StatusChecker的默认值覆盖。

JMX Health端点

Health是一个JMX (Java管理扩展)端点，加载于org.springframework.boot:type=Endpoint,name=Health，它可以由JMX代理管理。如JDK自带的工具jconsole等

内置StatusCheckers

META-INF/dubbo/internal/com.alibaba.dubbo.common.status.StatusChecker声明了内置StatusCheckers

registry=org.apache.dubbo.registry.status.RegistryStatusChecker
spring=org.apache.dubbo.config.spring.status.SpringStatusChecker
datasource=org.apache.dubbo.config.spring.status.DataSourceStatusChecker
memory=org.apache.dubbo.common.status.support.MemoryStatusChecker
load=org.apache.dubbo.common.status.support.LoadStatusChecker
server=org.apache.dubbo.rpc.protocol.dubbo.status.ServerStatusChecker
threadpool=org.apache.dubbo.rpc.protocol.dubbo.status.ThreadPoolStatusChecker

可以使用外部化配置中的management.health.dubbo.status.*的有效值，来作为StatusChecker名称的属性键

端点(Endpoints)

Actuator端点dubbo支持Actuator端点：

ID	Enabled	HTTP URI	HTTP Method	Description	Content Type
dubbo	true	/actuator/dubbo	GET	Exposes Dubbo’s meta data	application/json
dubboproperties	true	/actuator/dubbo/properties	GET	Exposes all Dubbo’s Properties	application/json
dubboservices	false	/dubbo/services	GET	Exposes all Dubbo’s ServiceBean	application/json
dubboreferences	false	/actuator/dubbo/references	GET	Exposes all Dubbo’s ReferenceBean	application/json
dubboconfigs	true	/actuator/dubbo/configs	GET	Exposes all Dubbo’s *Config	application/json
dubboshutdown	false	/actuator/dubbo/shutdown	POST	Shutdown Dubbo services	application/json

端点暴露的监控数据详见web-endpoints

外部化配置

默认的StatusChecker

management.health.dubbo.status.defaults是用于设置StatusCheckers名称的属性名称，其值允许为多个值，例如

management.health.dubbo.status.defaults = registry,memory,load

默认值为

management.health.dubbo.status.defaults = memory,load

StatusChecker额外功能

management.health.dubbo.status.extras用于覆盖StatusChecker的默认值，多个值由逗号分隔：

management.health.dubbo.status.extras = load,threadpool

健康检查启用

management.health.dubbo.enabled是一个启用配置来打开或关闭运行状况检查功能，其默认值为true。

如果您要禁用运行状况检查，则应将management.health.dubbo.enabled应用于false：

management.health.dubbo.enabled = false

端点启用

Dubbo Spring Boot提供执行器端点，但其中一些是禁用的。如果您要启用它们，请将以下属性添加到外部配置中：

# Enables Dubbo All Endpoints
management.endpoint.dubbo.enabled = true
management.endpoint.dubbo-shutdown.enabled = true
management.endpoint.dubbo-configs.enabled = true
management.endpoint.dubbo-services.enabled = true
management.endpoint.dubbo-references.enabled = true
management.endpoint.dubbo-properties.enabled = true

---

参考资料：
1.Dubbo Spring Boot Production-Ready
2.Securing HTTP Endpoints