Spring Boot Actuator学习笔记

spring boot Actuator

Actuator概述

Actuator指的是负责和移动装置的组件。通过Actuator暴露的端点我们可以获取一个正在运行中的应用内部的状态

导入依赖

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

Actuator具备一些开箱即用的端口

Endpoints id	描述	HTTP方法	是否敏感信息
auditevents	显示当前应用程序的审计事件信息	GET	Yes
beans	显示应用上下文中创建的所有Bean	GET	Yes
caches	显示可用缓存信息	GET	Yes
conditions	显示自动装配类的状态及及应用信息	GET	Yes
configprops	显示所有 @ConfigurationProperties 列表	GET	Yes
env	显示 ConfigurableEnvironment 中的属性	GET	Yes
flyway	显示 Flyway 数据库迁移信息	GET	Yes
health	显示应用的健康信息（未认证只显示status，认证显示全部信息详情）	GET	No
info	显示任意的应用信息（在资源文件写info.xxx即可）	GET	No
liquibase	展示Liquibase 数据库迁移	GET	Yes
metrics	提供应用运行状态的完整度量指标报告	GET	Yes
mappings	显示所有 @RequestMapping 路径集列表	GET	Yes
scheduledtasks	显示应用程序中的计划任务	GET	Yes
sessions	允许从Spring会话支持的会话存储中检索和删除用户会话。	GET	Yes
shutdown	允许应用以优雅的方式关闭（默认情况下不启用）	POST	Yes
threaddump	执行一个线程dump	GET	Yes
httptrace	显示HTTP跟踪信息（默认显示最后100个HTTP请求 - 响应交换）	GET	Yes

除了基于Http的端点之外，表中的所有除"/heapdump"的其他端点都以 JMX MBean的形式对外暴露出来

配置Actuator的基础路径

Actuator的前缀可以通过以下设置来进行更改

management:
  endpoints:
    web:
      base-path: /message

这样我们只需要向"/message/health"发送请求

启用和禁用端点

--- 启用所有端点
management:
  endpoints:
    web:
      exposure:
        include: "*"
        
--- 禁用指定端点
management:
  endpoints:
    web:
      exposure:
        exclude: health,info,beans

消费Actuator端点

为了了解Actuator提供了哪些端点，我们可以向Actuator发送一个get请求

{
  "_links": {
    "self": {
      "href": "http://localhost:8888/actuator",
      "templated": false
    },
    "archaius": {
      "href": "http://localhost:8888/actuator/archaius",
      "templated": false
    },
    "beans": {
      "href": "http://localhost:8888/actuator/beans",
      "templated": false
    },
    "caches-cache": {
      "href": "http://localhost:8888/actuator/caches/{cache}",
      "templated": true
    },
    "caches": {
      "href": "http://localhost:8888/actuator/caches",
      "templated": false
    },
    "health": {
      "href": "http://localhost:8888/actuator/health",
      "templated": false
    },
    "health-path": {
      "href": "http://localhost:8888/actuator/health/{*path}",
      "templated": true
    },
    "info": {
      "href": "http://localhost:8888/actuator/info",
      "templated": false
    },
    "conditions": {
      "href": "http://localhost:8888/actuator/conditions",
      "templated": false
    },
    "configprops": {
      "href": "http://localhost:8888/actuator/configprops",
      "templated": false
    }
      --------------

获取应用基本信息

"/info"告送我们关于应用的信息，"/health"端点则告送我们应用健康状况的信息。

请求应用信息 "/info"

$ curl localhost:8888/actuator/info
{}

发现并没有信息

我们可以通过配置文件基于infodua端点设置配置信息

info:
  contact:
    email: 1589391440@qq.com
    phone: 15684389579

再次发送请求

{
  "contact": {
    "email": "1589391440@qq.com",
    "phone": 15684389579
  }
}

应用健康情况

发送"/health"请求会得到一个简单的"/info"响应，其中包含了应用的健康状态。例如，如下是我们使用curl访问的结果

{"status":"up"}

这里显示的是一个或多个健康指示器的聚合状态。健康指示器会报告应用要与之交互的外部系统的健康状态，比如数据库、消息代理甚至SPring Cloud组件，比如Eureka和Config Server。每个指示器的健康状态可能会是下面的一个:

• UP:外部系统已经启动并且可以访问
• DOWN: 外部系统已经停机或者不可访问
• UNKNOWN: 外部系统的状态尚不清楚
• OUT_OF_SERVICE: 外部系统可以访问得到，但是目前不可用

所有健康指示器的状态会聚合成应用整体的健康状态，这个过程中会使用如下规则:

• UNKNOWN 的健康状态会被忽略，不会计入应用的聚合状态中。
• 其他的和单个指示器状态一样

默认情况下，只会包含聚合状态。但是我们可以设置

management:
  endpoint:
    health:
      show-details: always  # 默认值为never

always：总会显示健康状态器的完整细节； when-authorized，只有当客户端是完整认证的情况下才展示完整的细节信息

再次发送请求

{
  "status": "UP",
  "components": {
    "discoveryComposite": {
      "status": "UP",
      "components": {
        "discoveryClient": {
          "status": "UP",
          "details": {
            "services": [
              
            ]
          }
        },
        "eureka": {
          "description": "Eureka discovery client has not yet successfully connected to a Eureka server",
          "status": "UP",
          "details": {
            "applications": {
              
            }
          }
        }
      }
    },
  ---------------------------

其中有一个针对文件系统的健康指示器，名为diskSpace。它可以显示文件系统的状态情况，这个状态的值是由还有多少剩余空间绝定的。

查看配置细节

获取bean的装配报告

要研究Spring应用上下文，最基础的端点就是"/beans"。这个端点返回Json文档描述了应用上下文中的每个bean

{
  "contexts": {
    "application-1": {
      "beans": {
        "discoveryClientHealthIndicator": {
          "aliases": [
            
          ],
          "scope": "singleton",
          "type": "org.springframework.cloud.client.discovery.health.DiscoveryClientHealthIndicator",
          "resource": "class path resource [org/springframework/cloud/client/CommonsClientAutoConfiguration$DiscoveryLoadBalancerConfiguration.class]",
          "dependencies": [
            "org.springframework.cloud.client.CommonsClientAutoConfiguration$DiscoveryLoadBalancerConfiguration",
            "spring.cloud.discovery.client.health-indicator-org.springframework.cloud.client.discovery.health.DiscoveryClientHealthIndicatorProperties"
          ]
        },
        "org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration$RefreshableEurekaClientConfiguration": {
          "aliases": [
            
          ],
          "scope": "singleton",
          "type": "org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration$RefreshableEurekaClientConfiguration",
          "resource": null,
          "dependencies": [
            "discoveryClientOptionalArgs"
          ]
        },
        "inetUtils": {
          "aliases": [
            
          ],
          "scope": "singleton",
          "type": "org.springframework.cloud.commons.util.InetUtils",
          "resource": "class path resource [org/springframework/cloud/commons/util/UtilAutoConfiguration.class]",
          "dependencies": [
            "org.springframework.cloud.commons.util.UtilAutoConfiguration",
            "inetUtilsProperties"
          ]
        },
          
 -------------------------

​ 响应的根元素是contexts，它包含了一个子元素，代表应用中的每个Spring应用上下文。在每个应用上下文中，都有一个beans元素，它包含了应用上下文所有bean的细节。

• 自动装配

可以向"/conditions"端点发送自动装配报告 其中分为3部分: 匹配上的(positive matches,即已通过的条件化配置)、未配置上的(negative matches,即失败的条件化配置)以及非条件化的类。

{
  "contexts": {
    "application-1": {
      "positiveMatches": {
        "AuditEventsEndpointAutoConfiguration": [
          {
            "condition": "OnAvailableEndpointCondition",
            "message": "@ConditionalOnAvailableEndpoint no property management.endpoint.auditevents.enabled found so using endpoint default; @ConditionalOnAvailableEndpoint marked as exposed by a 'management.endpoints.jmx.exposure' property"
          }
        ],
        "BeansEndpointAutoConfiguration": [
          {
            "condition": "OnAvailableEndpointCondition",
            "message": "@ConditionalOnAvailableEndpoint no property management.endpoint.beans.enabled found so using endpoint default; @ConditionalOnAvailableEndpoint marked as exposed by a 'management.endpoints.jmx.exposure' property"
          }
        ],
        "BeansEndpointAutoConfiguration#beansEndpoint": [
          {
            "condition": "OnBeanCondition",
            "message": "@ConditionalOnMissingBean (types: org.springframework.boot.actuate.beans.BeansEndpoint; SearchStrategy: all) did not find any beans"
          }
        ],
 -----------------------------

​ 在positiveMatches区域中，我们可以看到通过自动配置创建了一个MongoTemplate bean，这是因为目前上下文中没有这样的bean。导致这种配置结果的原因是这里包含了@ConditionalOnMissingBean注解，如果没有明确配置这个bean，就会自动配置它

​ 在negativeMatches区域中，Spring Boot要尝试配置一个DispatcherServlet。但是，@ConditionalOnClass条件化注解失败了，这是因为没有找到DispatcherServlet类

最后，在 `unconditionalClasses`区域中是一个无条件配置的`ConfigurationPropertiesAutoConfiguration`。配置属性是Spring

Boot 操作的基础，所以任何与配置属性相关的配置都应该无条件自动装配。

探查环境和配置属性

​ "/env"获取spring应用中的所有属性元。包括: 环境变量、JVM系统属性、application.yml文件甚至来自Spring Cloud Config Server的属性

{
  "activeProfiles": [
    
  ],
  "propertySources": [
    {
      "name": "server.ports",
      "properties": {
        "local.server.port": {
          "value": 8888
        }
      }
    },
    {
      "name": "servletContextInitParams",
      "properties": {
        
      }
    },
    {
      "name": "systemProperties",
      "properties": {
        "java.runtime.name": {
          "value": "Java(TM) SE Runtime Environment"
        },
        "spring.output.ansi.enabled": {
          "value": "always"
        },
        "sun.boot.library.path": {
          "value": "D:\JavaEE\jdk-8\jre\bin"
        },
-----------------------------

• 还可以获取字段详情

$ curl localhost:8888/env/server.port
{
  "property": {
    "source": "applicationConfig: [classpath:/application.yml]",
    "value": 8888
  },
  "activeProfiles": [
    
  ],
  "propertySources": [
    {
      "name": "server.ports"
    },
    {
      "name": "servletConfigInitParams"
    },
    {
      "name": "servletContextInitParams"
    },
    {
      "name": "systemProperties"
    },
--------------------

也可以通过POST请求 对参数进行修改

curl localhost:8888/actuator/env  
      -d '{"name":"tacocloud.discount.code","value":"taco1314"}' 
      -H 'Content-type: application/json'
      
{"tacocloud.discount.code":"taco1314"}

修改后也可以进行删除 删除所有配置 这些数据都是临时的 重启后会消失

curl localhost:8081/actuator/env -X DELETE
{"tacocloud.discount.code":"taco1314"}

HTTP映射导览

​ Actuator的"/mappings"端点为应用中的所有HTTP请求处理器提供了一个一站式的视图，不管这些处理器来自Spring MVC控制器还是Actuator端点，我们都能一目了然的看清楚。要获取Spring Boot 应用中的所有端点的完整列表，我们只需要向"/mappings"发送get请求就可以了:

{
  "contexts": {
    "application-1": {
      "mappings": {
        "dispatcherServlets": {
          "dispatcherServlet": [
            {
              "handler": "Actuator web endpoint 'archaius'",
              "predicate": "{GET /actuator/archaius, produces [application/vnd.spring-boot.actuator.v3+json || application/vnd.spring-boot.actuator.v2+json || application/json]}",
              "details": {
                "handlerMethod": {
                  "className": "org.springframework.boot.actuate.endpoint.web.servlet.AbstractWebMvcEndpointHandlerMapping.OperationHandler",
                  "name": "handle",
                  "descriptor": "(Ljavax/servlet/http/HttpServletRequest;Ljava/util/Map;)Ljava/lang/Object;"
                },
                "requestMappingConditions": {
                  "consumes": [
                    
                  ],
                  "headers": [
                    
                  ],
                  "methods": [
                    "GET"
                  ],
                  "params": [
                    
                  ],
                  "patterns": [
                    "/actuator/archaius"
                  ],
                  "produces": [
                    {
                      "mediaType": "application/vnd.spring-boot.actuator.v3+json",
                      "negated": false
                    },
                    {
                      "mediaType": "application/vnd.spring-boot.actuator.v2+json",
                      "negated": false
                    },
                    {
                      "mediaType": "application/json",
                      "negated": false
                    }
                  ]
                }
              }
            },
 --------------------------

管理日志级别

可以向"/loggers"路径发送get请求

{
  "levels": [
    "OFF",
    "ERROR",
    "WARN",
    "INFO",
    "DEBUG",
    "TRACE"
  ],
  "loggers": {
    "ROOT": {
      "configuredLevel": "INFO",
      "effectiveLevel": "INFO"
    },
    "com": {
      "configuredLevel": null,
      "effectiveLevel": "INFO"
    },
    "com.itheim": {
      "configuredLevel": null,
      "effectiveLevel": "INFO"
    },
    "com.itheim.SpringCloudClientApplication": {
      "configuredLevel": null,
      "effectiveLevel": "INFO"
    },
    "com.netflix": {
      "configuredLevel": null,
      "effectiveLevel": "INFO"
    },
    "com.netflix.appinfo": {
      "configuredLevel": null,
      "effectiveLevel": "INFO"
    },
    "com.netflix.appinfo.ApplicationInfoManager": {
      "configuredLevel": null,
      "effectiveLevel": "INFO"
    },

其中，configuredLevel属性展示了明确配置的日志级别(如果没有明确配置，则显示为null)。

effectiveLevel属性展示的是实际的日志级别，它可能是从父包或根logger继承下来的。

如果想获取特定的包的日志级别 可以通过"/loggers/{包名}"

例如，你只想知道taco.ingredients包的日志级别，那么可以发送请求到"/loggers/tacos/ingredients"

 "configuredLevel": null,
 "effectiveLevel": "INFO"

• 也可以通过发送POST请求对日志进行修改

curl localhost:8888/actuator/loggers/tacos/ingredients
       -d '{"configuredLevel":"DEBUG"}'
       -H "Content-type:application/json"

现在日志级别发生了改变

{
	"configuredLevel":"DEBUG",
	"effectiveLevel":"DEBUG"
}

查看应用的活动

​ 如果我们能够时刻监视运行中应用的活动，Actuator提供了"/httptrace"、"/threaddump"、"/heapdump"端点。

跟踪HTTP活动

"/httptrace"端点能够报告应用所处理的最近100个请求的详情。

监控线程

”/threaddump“端点能够生成一个当前线程活动的快照。通过如下的"/threaddump"端点响应片段

{
  "threads": [
    {
      "threadName": "AsyncResolver-bootstrap-executor-0",
      "threadId": 95,
      "blockedTime": -1,
      "blockedCount": 0,
      "waitedTime": -1,
      "waitedCount": 56,
      "lockName": "java.util.concurrent.SynchronousQueue$TransferStack@7022e838",
      "lockOwnerId": -1,
      "lockOwnerName": null,
      "inNative": false,
      "suspended": false,
      "threadState": "WAITING",
      "stackTrace": [
        {
          "methodName": "park",
          "fileName": "Unsafe.java",
          "lineNumber": -2,
          "className": "sun.misc.Unsafe",
          "nativeMethod": true
        },
        {
          "methodName": "park",
          "fileName": "LockSupport.java",
          "lineNumber": 175,
          "className": "java.util.concurrent.locks.LockSupport",
          "nativeMethod": false
        },
        {
          "methodName": "awaitFulfill",
          "fileName": "SynchronousQueue.java",
          "lineNumber": 458,
          "className": "java.util.concurrent.SynchronousQueue$TransferStack",
          "nativeMethod": false
        },
        {
          "methodName": "transfer",
          "fileName": "SynchronousQueue.java",
          "lineNumber": 362,
          "className": "java.util.concurrent.SynchronousQueue$TransferStack",
          "nativeMethod": false
        },

这里包含了线程阻塞和锁定状态，以及其他线程的细节

获取应用的指标

"/metrics"端点可以获取应用运行过程中的各项指标，包括 内存、处理器、垃圾收集

{
  "names": [
    "http.server.requests",
    "jvm.buffer.count",
    "jvm.buffer.memory.used",
    "jvm.buffer.total.capacity",
    "jvm.classes.loaded",
    "jvm.classes.unloaded",
    "jvm.gc.live.data.size",
    "jvm.gc.max.data.size",
    "jvm.gc.memory.allocated",
    "jvm.gc.memory.promoted",
    "jvm.gc.pause",
    "jvm.memory.committed",
    "jvm.memory.max",
    "jvm.memory.used",
    "jvm.threads.daemon",
    "jvm.threads.live",
    "jvm.threads.peak",
    "jvm.threads.states",
    "logback.events",
    "process.cpu.usage",
    "process.start.time",
    "process.uptime",
    "system.cpu.count",
    "system.cpu.usage",
    "tomcat.sessions.active.current",
    "tomcat.sessions.active.max",
    "tomcat.sessions.alive.max",
    "tomcat.sessions.created",
    "tomcat.sessions.expired",
    "tomcat.sessions.rejected"
  ]
}

我们可以只针对一个指标 获取"http.server.requests"信息

{
  "name": "http.server.requests",
  "description": null,
  "baseUnit": "seconds",
  "measurements": [
    {
      "statistic": "COUNT",
      "value": 20.0
    },
    {
      "statistic": "TOTAL_TIME",
      "value": 0.883478498
    },
    {
      "statistic": "MAX",
      "value": 0.0
    }
  ],
  "availableTags": [
    {
      "tag": "exception",
      "values": [
        "None",
        "HttpRequestMethodNotSupportedException"
      ]
    },
    {
      "tag": "method",
      "values": [
        "post",
        "POST",
        "GET"
      ]
    },
    {
      "tag": "uri",
      "values": [
        "/actuator/metrics/{requiredMetricName}",
        "/actuator/beans",
        "/actuator/threaddump",
        "root",
        "/actuator/health",
        "/actuator/env/{toMatch}",
        "/actuator/loggers",
        "/actuator/mappings",
        "/actuator/metrics",
        "/actuator/conditions",
        "/**",
        "/actuator/env"
      ]
    },
    {
      "tag": "outcome",
      "values": [
        "CLIENT_ERROR",
        "SUCCESS"
      ]
    },
    {
      "tag": "status",
      "values": [
        "404",
        "405",
        "200"
      ]
    }
  ]
}

最重要的组成为measurements区域，它包含了所请求分类的所有指标数据。在本例中，它表示一共有200个体Http请求，处理这些请求的总耗时为0.883478498秒，处理单个请求为0.0秒

如果我们向具体到请求状态为多少的请求 可以使用status:404获取请求状态为404的请求

$ curl localhost:8888/actuator/metrics/http.server.requests?tag=status:404
{
  "name": "http.server.requests",
  "description": null,
  "baseUnit": "seconds",
  "measurements": [
    {
      "statistic": "COUNT",
      "value": 3.0
    },
    {
      "statistic": "TOTAL_TIME",
      "value": 0.09725639999999999
    },
    {
      "statistic": "MAX",
      "value": 0.0
    }
  ],
  "availableTags": [
    {
      "tag": "exception",
      "values": [
        "None"
      ]
    },
    {
      "tag": "method",
      "values": [
        "GET"
      ]
    },
    {
      "tag": "uri",
      "values": [
        "/actuator/env/{toMatch}",
        "/**"
      ]
    },
    {
      "tag": "outcome",
      "values": [
        "CLIENT_ERROR"
      ]
    }
  ]
}

我们可以看到一些失败请求的路径为"/actuator/env/{toMatch}", "/**"，有些是发送到其他路径是通过"/"获取的**

// $ curl localhost:8888/actuator/metrics/http.server.requests?tag=status:404&tag=uri:/**
{
  "name": "http.server.requests",
  "description": null,
  "baseUnit": "seconds",
  "measurements": [
    {
      "statistic": "COUNT",
      "value": 2.0
    },
    {
      "statistic": "TOTAL_TIME",
      "value": 0.0932196
    },
    {
      "statistic": "MAX",
      "value": 0.0
    }
  ],
  "availableTags": [
    {
      "tag": "exception",
      "values": [
        "None"
      ]
    },
    {
      "tag": "method",
      "values": [
        "GET"
      ]
    },
    {
      "tag": "outcome",
      "values": [
        "CLIENT_ERROR"
      ]
    }
  ]
}

自定义Actuator

创建自定义的Info贡献者

​ 我们为"/info"端点添加关于taco的信息，为了实现这一点我们需要编写并实现InfoContributor端口的类，并将信息提供到"/info"端点。

@Component
public class TacoInfoContributor implements org.springframework.boot.actuate.info.InfoContributor {


    @Override
    public void contribute(Info.Builder builder) {
        int i=10;
        HashMap<String, Object> map = new HashMap<>();
        //设置数量
        map.put("count",i);
        //添加详情信息
        builder.withDetail("taco-stats",map);
    }
}

{
  "taco-stats": {
    "count": 10
  }
}

注入构建信息到"/info"端点中

​ ·Spring Boot提供了一些内置的InfoContributor实现，他们能够自动添加信息到"/info"端点的结果中。其中有一个实现是BuildInfoContributor，它能够将项目构建文件中的信息添加到"/info"端点的结果中。这包括了一些基本信息，比如项目版本、构建的时间戳以及执行构建的主机和用户。

​ 添加插件 build-info goal到Spring Boot maven中

           <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>build-info</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

先通过插件构建

• 然后访问info端点 得到下面的结果

{
  "build": {
    "version": "1.0-SNAPSHOT",
    "artifact": "spring-cloud-client",
    "name": "spring-cloud-client",
    "group": "org.example",
    "time": "2021-02-01T04:46:43.664Z"
  },
  "taco-stats": {
    "count": 10
  }
}

暴露Git提交信息

​ 假设我们的项目使用git进行源码控制，那么我们可以在"/info"端点中包含Git提交信息

           <plugin>
                <groupId>pl.project13.maven</groupId>
                <artifactId>git-commit-id-plugin</artifactId>
            </plugin>

然后创建git版本库

git init
git add .
git commit -m "首次提交"

• 访问端点得到信息

 "git": {
    "commit": {
      "time": "2021-02-01T04:58:19Z",
      "id": "c9ce0d2"
    },
    "branch": "master"
  },

• 如果想获取详细的git信息可以 设置yml属性

 info:
    git:
      mode: full

{
  "git": {
    "build": {
      "host": "DESKTOP-TP0O298",
      "version": "1.0-SNAPSHOT",
      "time": "2021-02-01T05:01:41Z",
      "user": {
        "name": "ZGrey",
        "email": "1589391440@qq.com"
      }
    },
    "branch": "master",
    "commit": {
      "message": {
        "short": "11",
        "full": "11"
      },
      "id": {
        "describe": "c9ce0d2",
        "abbrev": "c9ce0d2",
        "describe-short": "c9ce0d2",
        "full": "c9ce0d20ab5f503631f8055df6e115817a6cd487"
      },
      "time": "2021-02-01T04:58:19Z",
      "user": {
        "email": "1589391440@qq.com",
        "name": "ZGrey"
      }
    },
    "closest": {
      "tag": {
        "name": "",
        "commit": {
          "count": ""
        }
      }
    },
    "local": {
      "branch": {
        "ahead": "NO_REMOTE",
        "behind": "NO_REMOTE"
      }
    },
    "dirty": "false",
    "remote": {
      "origin": {
        "url": "Unknown"
      }
    },
    "tags": "",
    "total": {
      "commit": {
        "count": "2"
      }
    }
  },

创建自定义的指标

"/metrics"是由Micrometer实现的。这是一个供应商中立的指标门面，借助它，我们能够发送任意想要的指标，并在所选的第三方监控系统中对其进行展现。他提供了对Prometheus、Datadog和New Relic等系统的支持。

创建自定义的端点

Actuator的定义与控制器有很大的差异。Actuator端点并不是使用@Controller或@RestController注解来标注类，而是通过为类添加@Endpoint注解来实现的。

​ 另外，他们不是使用Http方法命名的注解，如@GetMapping、@PostMapping、@DeleteMapping，Actuator端点的操作是通过添加

@ReadOperation、@WriteOperation、@DeleteOperation注解实现的。这些注解并没有指明任何的通信机制，实际上，这允许Actuator与各种各样的通信机制协作，内置了对HTTP和JMX的支持

package com.itheim.endpoint;

import org.springframework.boot.actuate.endpoint.annotation.DeleteOperation;
import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
import org.springframework.boot.actuate.endpoint.annotation.WriteOperation;
import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.List;

/**
 * @program: spring-cloud
 * @description:
 * @author: Mr.ZGrey
 * @create: 2021-02-01 19:32
 **/
@Component
@Endpoint(id = "notes",enableByDefault = true)
public class NotesEndpoint   {
    private List<Note> notes=new ArrayList<>();
    @ReadOperation
    public List<Note> notes(){
        return notes;
    }

    @WriteOperation
    public List<Note> addNote(String text){
        notes.add(new Note(text));
        return notes;
    }

    @DeleteOperation
    public List<Note> deleteNote(int index){
        if (index<notes.size()){
            notes.remove(index);
        }
        return notes;
    }

}

• Node类需要编写

我们可以通过POST请求对端点notes进行测试

curl localhost:8888/actuator/notes  -d'{"text":"hello"}' -H"Content-type:application/json"
[{"text":"hello"}]

当新增时端点数量会增加

$ curl localhost:8888/actuator/notes
[{"text":"hello"}]

• 删除笔记 Delete请求

localhost:8888/actuator/notes?index=1  -X DELETE
[{"text":"hello"}]

• 如果只想暴露HTTP端点，那么可以使用@WebEndpoint注解而不是@Endpoint来标注端点类:

@Component
//@Endpoint(id = "notes",enableByDefault = true)
@WebEndpoint(id="notes",enableByDefault = true)
public class NotesEndpoint   {
       ----------------------
}

类似的如果只想暴露MBean端点，可以使用@JmxEndpoint注解进行标注

保护Actuator

我们可以通过使用Spring security对Actuator进行访问保护

public class ActuatorSecurity extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
                .antMatchers("/actuator/**")
                .hasRole("ADMIN")
                .and()
                .httpBasic();
    }

}

• 为了解除硬编码的"/actuator/**"设置 spring Boot 提供了EndpointRequest(一个请求匹配类，更简单，而且不依赖于给定的String路径) 我们可以通过以下方式获取

   @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
                .requestMatchers(EndpointRequest.toAnyEndpoint())
                .hasRole("ADMIN")
                .and()
                .httpBasic();
    }

EndpointRequest.toAnyEndpoint()方法会返回一个请求匹配器，它会匹配所有的Actuator端点。如果你想要将某些端点从请求匹配器中移除，那么可以电泳excluding()方法

 @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
                .requestMatchers(EndpointRequest.toAnyEndpoint().excluding("health","env"))
                .hasRole("ADMIN")
                .and()
                .httpBasic();
    }

• 另外我们只想用到一部分，可以使用以下方式获取

  @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
                .requestMatchers(EndpointRequest.to("env","health"))
                .hasRole("ADMIN")
                .and()
                .httpBasic();
    }

这样的话只会保护"env"和"health"端点，其他的端点会全部对外开放

• 小结

Spring Boot Actuator 以Http和JMX MBean的形式提供了多个断点。