跟我学Spring Cloud(Finchley版)-03-监控:强大的Spring Boot Actuator

第2节( 跟我学Spring Cloud(Finchley版)-02-构建分布式应用 )说过:

应用没有监控,没有画板,一切指标都没有。在这个Growth Hack逐渐成为主流的时代,不弄个Dashboard把系统压力、QPS、CPU、内存、日活啥的可视化,你好意思出来混吗……

本节我们来解决该问题。

Spring Boot Actuator是Spring Boot官方提供的监控组件。只需为项目添加以下依赖,即可就整合Spring Boot Actuator。

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

监控端点

Actuator为我们提供了很多监控端点,如下表所示。

端点(Spring Boot 2.x) 描述 HTTP方法 是否敏感 端点(Spring Boot 1.x)
conditions 显示自动配置的信息 GET autoconfig
beans 显示应用程序上下文所有的Spring bean GET beans
configprops 显示所有@ConfigurationProperties的配置属性列表 GET configprops
dump 显示线程活动的快照 GET dump
env 显示环境变量,包括系统环境变量以及应用环境变量 GET env
health 显示应用程序的健康指标,值由HealthIndicator的实现类提供;结果有UP、 DOWN、OUT_OF_SERVICE、UNKNOWN;如需查看详情,需配置:management.endpoint.health.show-details GET health
info 显示应用的信息,可使用info.* 属性自定义info端点公开的数据 GET info
mappings 显示所有的URL路径 GET mappings
metrics 显示应用的度量标准信息 GET metrics

表-Spring Boot Actuator常用端点及描述

只需访问http://{ip}:{port}/actuator/{endpoint} 端点,即可监控应用的运行状况。

测试1:/health端点

为前文编写的microservice-simple-provider-user 服务整合Actuator后,我们来做一些测试:

访问http://localhost:8000/actuator/health ,即可获得如下结果:

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{"status":"UP"}

测试2:/health端点展示详情

/health 端点配置显示详情:

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management:
endpoint:
health:
# 是否展示健康检查详情
show-details: always

再次访问http://localhost:8000/actuator/health ,即可获得如下结果:

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{
"status": "UP",
"details": {
"db": {
"status": "UP",
"details": {
"database": "H2",
"hello": 1
}
},
"diskSpace": {
"status": "UP",
"details": {
"total": 250790436864,
"free": 43443773440,
"threshold": 10485760
}
}
}
}

从中可以看到,/health 端点展示了DB的健康情况以及磁盘的健康情况。

测试3:暴露敏感路径

默认情况下,敏感路径并不暴露。如需暴露(以metrics为例),需添加配置:

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management:
endpoints:
web:
exposure:
# 暴露metrics端点,如需暴露多个,用,分隔;如需暴露所有端点,用'*'
include: metrics

访问:http://localhost:8000/actuator/metrics ,可获得类似如下的结果:

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{
"names": ["jvm.memory.max", "http.server.requests", "jdbc.connections.active", "process.files.max", "jvm.gc.memory.promoted", "tomcat.cache.hit", "system.load.average.1m", "tomcat.cache.access", "jvm.memory.used", "jvm.gc.max.data.size", "jdbc.connections.max", "jdbc.connections.min", "jvm.gc.pause", "jvm.memory.committed", "system.cpu.count", "logback.events", "tomcat.global.sent", "jvm.buffer.memory.used", "tomcat.sessions.created", "jvm.threads.daemon", "system.cpu.usage", "jvm.gc.memory.allocated", "tomcat.global.request.max", "hikaricp.connections.idle", "hikaricp.connections.pending", "tomcat.global.request", "tomcat.sessions.expired", "hikaricp.connections", "jvm.threads.live", "jvm.threads.peak", "tomcat.global.received", "hikaricp.connections.active", "hikaricp.connections.creation", "process.uptime", "tomcat.sessions.rejected", "process.cpu.usage", "tomcat.threads.config.max", "jvm.classes.loaded", "hikaricp.connections.max", "hikaricp.connections.min", "jvm.classes.unloaded", "tomcat.global.error", "tomcat.sessions.active.current", "tomcat.sessions.alive.max", "jvm.gc.live.data.size", "tomcat.servlet.request.max", "hikaricp.connections.usage", "tomcat.threads.current", "tomcat.servlet.request", "hikaricp.connections.timeout", "process.files.open", "jvm.buffer.count", "jvm.buffer.total.capacity", "tomcat.sessions.active.max", "hikaricp.connections.acquire", "tomcat.threads.busy", "process.start.time", "tomcat.servlet.error"]
}

访问http://localhost:8000/actuator/metrics/{name}{name} 列表如上,即可查看当前应用的度量指标。例如访问:http://localhost:8000/actuator/metrics/jvm.memory.max 即可查看JVM可管理的最大内存,结果类似如下:

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{
"name": "jvm.memory.max",
"description": "The maximum amount of memory in bytes that can be used for memory management",
"baseUnit": "bytes",
"measurements": [{
"statistic": "VALUE",
"value": 5.597298687E9
}],
"availableTags": [{
"tag": "area",
"values": ["heap", "nonheap"]
}, {
"tag": "id",
"values": ["Compressed Class Space", "PS Survivor Space", "PS Old Gen", "Metaspace", "PS Eden Space", "Code Cache"]
}]
}

TIPS

  • 如需暴露所有监控端点可配置:

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    management:
    endpoints:
    web:
    exposure:
    include: '*'

拓展阅读

如果能对Actuator端点的文字数据进行图形化的展示,我们就可以实现比较低层次的“Growth Hack”啦!开源界已经有这样的工具——Spring Boot Admin ,界面如下。有兴趣的可前往https://github.com/codecentric/spring-boot-admin了解。

trace

说明

  • 由于Actuator本身是Spring Boot中的组件,并不是本套教程的重点(其实笔者本不想写这一节,但后面又会持续用这些端点,并且Spring Cloud在这些端点的基础上还做了一些增加,所以还是有必要介绍一下),因此本节只是对Actuator进行了比较简单的介绍,读者可自行挖掘Actuator的其他能力。也可持续关注本公众号,本系列完成后,笔者将会扒开Actuator的底裤,深度介绍Spring Boot监控的那些事儿。

配套代码

GitHub:

Gitee:

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