spring-boot 速成(3) actuator

actuator 通过暴露一系列的endpoints可以让开发者快速了解spring boot的各项运行指标,比如:线程数,jvm剩余内存等一系列参数。

启用方法很简单,参考下面:

dependencies {
    compile('org.springframework.boot:spring-boot-starter-thymeleaf')
    compile('org.springframework.boot:spring-boot-devtools')
    compile('org.springframework.boot:spring-boot-starter-actuator')
    compile('org.springframework.boot:spring-boot-starter-test')
    compileOnly('org.projectlombok:lombok')
}  

关键是添加spring-boot-starter-actuator依赖项即可,下表是actuator提供的endpoints列表(从官网文档上抄过来的)

IDDescriptionSensitive Default

actuator

Provides a hypermedia-based “discovery page” for the other endpoints.Requires Spring HATEOAS to be on the classpath.

true

auditevents

Exposes audit events information for the current application.

true

autoconfig

Displays an auto-configuration report showing all auto-configuration candidates and the reason why they ‘were’ or ‘were not’ applied.

true

beans

Displays a complete list of all the Spring beans in your application.

true

configprops

Displays a collated list of all @ConfigurationProperties.

true

dump

Performs a thread dump.

true

env

Exposes properties from Spring’s ConfigurableEnvironment.

true

flyway

Shows any Flyway database migrations that have been applied.

true

health

Shows application health information (when the application is secure,

a simple ‘status’ when accessed over an unauthenticated connection or

full message details when authenticated).

false

info

Displays arbitrary application info.

false

loggers

Shows and modifies the configuration of loggers in the application.

true

liquibase

Shows any Liquibase database migrations that have been applied.

true

metrics

Shows ‘metrics’ information for the current application.

true

mappings

Displays a collated list of all @RequestMapping paths.

true

shutdown

Allows the application to be gracefully shutdown (not enabled by default).

true

trace

Displays trace information (by default the last 100 HTTP requests).

true

这张表中,有很多信息其实是敏感信息,并不适合匿名访问(特别是在公网环境下),所以默认情况下,如果想访问类似 http://localhost:8081/metrics 会看到以下错误:

比较好的做法是,将这些endpoints的端口,包括访问路径与常规应用的端口分开,application.yml可以参考下面的配置:

server:
  port: 8081
spring:
  main:
    banner-mode: "off"
  devtools:
    restart:
      trigger-file: .trigger
  thymeleaf:
    cache: false
management:
  security:
    enabled: false #关掉安全认证
  port: 1101 #管理端口调整成1101
  context-path: /admin #actuator的访问路径  

如果在公网环境,建议在防火墙上做下限制,仅允许8081进来,1101用于内网访问即可,这样相对比较安全,也不用繁琐的输入密码。

访问下http://localhost:1101/admin/metrics 可以看到类似以下输出:

{
	mem: 466881,
	mem.free: 289887,
	processors: 4,
	instance.uptime: 10947,
	uptime: 18135,
	systemload.average: 3.12646484375,
	heap.committed: 411648,
	heap.init: 131072,
	heap.used: 121760,
	heap: 1864192,
	nonheap.committed: 56192,
	nonheap.init: 2496,
	nonheap.used: 55234,
	nonheap: 0,
	threads.peak: 27,
	threads.daemon: 19,
	threads.totalStarted: 32,
	threads: 22,
	classes: 6755,
	classes.loaded: 6755,
	classes.unloaded: 0,
	gc.ps_scavenge.count: 8,
	gc.ps_scavenge.time: 136,
	gc.ps_marksweep.count: 2,
	gc.ps_marksweep.time: 193,
	httpsessions.max: -1,
	httpsessions.active: 0
}

jvm的内存,cpu核数,线程数,gc情况一目了然,再结合其它一些工具把这些信息采集到grafana里,就有得到一系列很实用的监控图表数据,比如:  

其它endpoint,就不一一展示了,大家有兴趣可以自行研究,最后要提一下的是shutdown这个endpoint,它可以实现优雅停机,这在线上部署时很有用,发布前先调用这个url,让应用优雅停掉,再部署新的代码,这样就不会导致正在处理的请求被中断,不过默认该功能是关闭的,可参考下面的设置启用:

endpoints:
  shutdown:
    enabled: true 

而且出于安全考虑,该url只能以post方式访问,下图是用postman模拟post访问 http://locahost:1101/admin/shutdown的效果:

同时在日志里也能看到应用确实被关闭:

 

 

参考文章:

http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#production-ready

posted @ 2017-04-15 14:02 菩提树下的杨过 阅读(...) 评论(...) 编辑 收藏