Spring Boot Actuator:健康检查、审计、统计和监控

通过JMX暴露Actuator endpoints。

{"_links":{"self":{"href":"http://localhost:8080/actuator","templated":false},"auditevents":{"href":"http://localhost:8080/actuator/auditevents","templated":false},"beans":{"href":"http://localhost:8080/actuator/beans","templated":false},"health":{"href":"http://localhost:8080/actuator/health","templated":false},"conditions":{"href":"http://localhost:8080/actuator/conditions","templated":false},"configprops":{"href":"http://localhost:8080/actuator/configprops","templated":false},"env":{"href":"http://localhost:8080/actuator/env","templated":false},"env-toMatch":{"href":"http://localhost:8080/actuator/env/{toMatch}","templated":true},"info":{"href":"http://localhost:8080/actuator/info","templated":false},"loggers":{"href":"http://localhost:8080/actuator/loggers","templated":false},"loggers-name":{"href":"http://localhost:8080/actuator/loggers/{name}","templated":true},"heapdump":{"href":"http://localhost:8080/actuator/heapdump","templated":false},"threaddump":{"href":"http://localhost:8080/actuator/threaddump","templated":false},"prometheus":{"href":"http://localhost:8080/actuator/prometheus","templated":false},"metrics-requiredMetricName":{"href":"http://localhost:8080/actuator/metrics/{requiredMetricName}","templated":true},"metrics":{"href":"http://localhost:8080/actuator/metrics","templated":false},"scheduledtasks":{"href":"http://localhost:8080/actuator/scheduledtasks","templated":false},"httptrace":{"href":"http://localhost:8080/actuator/httptrace","templated":false},"mappings":{"href":"http://localhost:8080/actuator/mappings","templated":false}}}

解析常用的actuator endpoint

/health endpoint

health endpoint通过合并几个健康指数检查应用的健康情况。

Spring Boot Actuator有几个预定义的健康指标比如DataSourceHealthIndicator, DiskSpaceHealthIndicator, MongoHealthIndicator, RedisHealthIndicator, CassandraHealthIndicator等。它使用这些健康指标作为健康检查的一部分。

举个例子，如果你的应用使用Redis，RedisHealthindicator将被当作检查的一部分。如果使用MongoDB，那么MongoHealthIndicator将被当作检查的一部分。

你也可以关闭特定的健康检查指标，比如在prpperties中使用如下命令：

management:
  endpoint:
    health:
      show-details: always

一旦你打开上述开关，你在/health中可以看到如下详细内容：

{
   "status":"UP",
   "details":{
      "db":{
         "status":"UP",
         "details":{
            "database":"MySQL",
            "hello":1
         }
      },
      "diskSpace":{
         "status":"UP",
         "details":{
            "total":250790436864,
            "free":100330897408,
            "threshold":10485760
         }
      }
   }
}

如果你的MySQL server没有启起来，状态将会变成DOWN：

package com.example.actuator.health;

import org.springframework.boot.actuate.health.AbstractHealthIndicator;
import org.springframework.boot.actuate.health.Health;
import org.springframework.stereotype.Component;

@Component
public class CustomHealthIndicator extends AbstractHealthIndicator {

    @Override
    protected void doHealthCheck(Health.Builder builder) throws Exception {
        // Use the builder to build the health status details that should be reported.
        // If you throw an exception, the status will be DOWN with the exception message.
        
        builder.up()
                .withDetail("app", "Alive and Kicking")
                .withDetail("error", "Nothing! I'm good.");
    }
}

一旦你增加上面的健康指标到你的应用中去后，health endpoint将展示如下细节:

{
    "names": [
        "jvm.memory.max",
        "http.server.requests",
        "process.files.max",
        ...
        "tomcat.threads.busy",
        "process.start.time",
        "tomcat.servlet.error"
    ]
}

想要获得每个度量的详细信息，你需要传递度量的名称到URL中，像

http://localhost:8080/actuator/metrics/{MetricName}

举个例子，获得systems.cpu.usage的详细信息，使用以下URLhttp://localhost:8080/actuator/metrics/system.cpu.usage。它将显示如下内容:

{
   "configuredLevel":"INFO",
   "effectiveLevel":"INFO"
}

在运行时改变日志等级

loggers endpoint也允许你在运行时改变应用的日志等级。

举个例子，为了改变root logger的等级为DEBUG ，发送一个POST请求到http://localhost:8080/actuator/loggers/root，加入如下参数

# INFO ENDPOINT CONFIGURATION
info:
  app:
    name: @project.name@
    description: @project.description@
    version: @project.version@
    encoding: @project.build.sourceEncoding@
    java:
      version: @java.version@

注意，我使用了Spring Boot的Automatic property expansion 特征来扩展来自maven工程的properties。

一旦你增加上面的properties，info endpoint将展示如下信息：

>
   >org.springframework.boot>
   >spring-boot-starter-security>
>

接下去让我们看一下如何覆写spring security配置，并且定义你自己的进入规则。

下面的例子展示了一个简单的spring securiy配置。它使用叫做EndPointRequest

的ReqeustMatcher工厂模式来配置Actuator endpoints进入规则。

# Spring Security Default user name and password
spring:
  security:
    user:
      name: actuator
      password: actuator
      roles: ACTUATOR_ADMIN

你可以在Github上看到完整的代码。

下一部分：Spring Boot Metrics监控之Prometheus&Grafana

更多学习资源

• Spring Boot Actuator: Production-ready features
• Micrometer: Spring Boot 2’s new application metrics collector

翻译源

• Spring Boot Actuator: Health check, Auditing, Metrics gathering and Monitoring