Spring Boot Actuator幫助我們實現了許多中間件比如mysql、es、redis、mq等中間件的健康指示器。
通過 Spring Boot 的自動配置,這些指示器會自動生效。當這些組件有問題的時候,HealthIndicator 會返回 DOWN 或 OUT_OF_SERVICE 狀態,health 端點 HTTP 響應狀態碼也會變爲 503,我們可以以此來配置程序健康狀態監控報警。
使用步驟也非常簡單,這裏演示的是線程池的監控。模擬線程池滿了狀態下將HealthInicator指示器變爲Down的狀態。
pom中引入jar
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
引入properties配置
spring.application.name=boot
# server.servlet.context-path=/boot
# management.server.servlet.context-path=/boot
# JVM (Micrometer)要求給應用設置commonTag
management.metrics.tags.application=${spring.application.name}
#去掉重複的metrics
spring.metrics.servo.enabled=false
management.endpoint.metrics.enabled=true
management.endpoint.metrics.sensitive=false
#顯式配置不需要權限驗證對外開放的端點
management.endpoints.web.exposure.include=*
management.endpoints.jmx.exposure.include=*
management.endpoint.health.show-details=always
#Actuator 的 Web 訪問方式的根地址爲 /actuator,可以通過 management.endpoints.web.base-path 參數進行修改
management.endpoints.web.base-path=/actuator
management.metrics.export.prometheus.enabled=true
代碼
/**
* @Author jeffSmile
* @Date 下午 6:10 2020/5/24 0024
* @Description 定義一個接口,來把耗時很長的任務提交到這個 demoThreadPool 線程池,以模擬線程池隊列滿的情況
**/
@GetMapping("slowTask")
public void slowTask() {
ThreadPoolProvider.getDemoThreadPool().execute(() -> {
try {
TimeUnit.HOURS.sleep(1);
} catch (InterruptedException e) {
}
});
}
package com.mongo.boot.service;
import jodd.util.concurrent.ThreadFactoryBuilder;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class ThreadPoolProvider {
//一個工作線程的線程池,隊列長度10
private static ThreadPoolExecutor demoThreadPool = new ThreadPoolExecutor(
1, 1,
2, TimeUnit.SECONDS,
new ArrayBlockingQueue<>(10),
new ThreadFactoryBuilder().setNameFormat("demo-threadpool-%d").get());
//核心線程數10,最大線程數50的線程池,隊列長度50
private static ThreadPoolExecutor ioThreadPool = new ThreadPoolExecutor(
10, 50,
2, TimeUnit.SECONDS,
new ArrayBlockingQueue<>(100),
new ThreadFactoryBuilder().setNameFormat("io-threadpool-%d").get());
public static ThreadPoolExecutor getDemoThreadPool() {
return demoThreadPool;
}
public static ThreadPoolExecutor getIOThreadPool() {
return ioThreadPool;
}
}
package com.mongo.boot.service;
import org.springframework.boot.actuate.health.Health;
import org.springframework.boot.actuate.health.HealthIndicator;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ThreadPoolExecutor;
/**
* @Author jeffSmile
* @Date 下午 6:12 2020/5/24 0024
* @Description 自定義的 HealthIndicator 類,用於單一線程池的健康狀態
**/
public class ThreadPoolHealthIndicator implements HealthIndicator {
private ThreadPoolExecutor threadPool;
public ThreadPoolHealthIndicator(ThreadPoolExecutor threadPool) {
this.threadPool = threadPool;
}
@Override
public Health health() {
//補充信息
Map<String, Integer> detail = new HashMap<>();
//隊列當前元素個數
detail.put("queue_size", threadPool.getQueue().size());
//隊列剩餘容量
detail.put("queue_remaining", threadPool.getQueue().remainingCapacity());
//如果還有剩餘量則返回UP,否則返回DOWN
if (threadPool.getQueue().remainingCapacity() > 0) {
return Health.up().withDetails(detail).build();
} else {
return Health.down().withDetails(detail).build();
}
}
}
package com.mongo.boot.service;
import org.springframework.boot.actuate.health.CompositeHealthContributor;
import org.springframework.boot.actuate.health.HealthContributor;
import org.springframework.boot.actuate.health.NamedContributor;
import org.springframework.stereotype.Component;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/***
* @Author jeffSmile
* @Date 下午 6:13 2020/5/24 0024
* @Description 定義一個 CompositeHealthContributor,來聚合兩個 ThreadPoolHealthIndicator 的實例,
* 分別對應 ThreadPoolProvider 中定義的兩個線程池
**/
@Component
public class ThreadPoolsHealthContributor implements CompositeHealthContributor {
//保存所有的子HealthContributor
private Map<String, HealthContributor> contributors = new HashMap<>();
ThreadPoolsHealthContributor() {
//對應ThreadPoolProvider中定義的兩個線程池
this.contributors.put("demoThreadPool", new ThreadPoolHealthIndicator(ThreadPoolProvider.getDemoThreadPool()));
this.contributors.put("ioThreadPool", new ThreadPoolHealthIndicator(ThreadPoolProvider.getIOThreadPool()));
}
@Override
public HealthContributor getContributor(String name) {
//根據name找到某一個HealthContributor
return contributors.get(name);
}
@Override
public Iterator<NamedContributor<HealthContributor>> iterator() {
//返回NamedContributor的迭代器,NamedContributor也就是Contributor實例+一個命名
return contributors.entrySet().stream()
.map((entry) -> NamedContributor.of(entry.getKey(), entry.getValue())).iterator();
}
}
啓動springboot驗證
這裏我訪問:http://localhost:8080/slowTask
每次訪問都向demo線程池中提交一個耗時1小時的任務,而demo線程池的核心和最大線程數都是1,隊列長度爲10,那麼當訪問11次之後,任務將被直接拒絕掉!
此時訪問:http://localhost:8080/actuator/health
demo線程池隊列已經滿了,狀態變爲DOWN。
監控內部重要組件的狀態數據
通過 Actuator 的 InfoContributor 功能,對外暴露程序內部重要組件的狀態數據!
實現一個 ThreadPoolInfoContributor 來展現線程池的信息:
package com.mongo.boot.config;
import com.mongo.boot.service.ThreadPoolProvider;
import org.springframework.boot.actuate.info.Info;
import org.springframework.boot.actuate.info.InfoContributor;
import org.springframework.stereotype.Component;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ThreadPoolExecutor;
/**
* @Author jeffSmile
* @Date 下午 6:37 2020/5/24 0024
* @Description 通過 Actuator 的 InfoContributor 功能,對外暴露程序內部重要組件的狀態數據
**/
@Component
public class ThreadPoolInfoContributor implements InfoContributor {
private static Map threadPoolInfo(ThreadPoolExecutor threadPool) {
Map<String, Object> info = new HashMap<>();
info.put("poolSize", threadPool.getPoolSize());//當前池大小
info.put("corePoolSize", threadPool.getCorePoolSize());//設置的核心池大小
info.put("largestPoolSize", threadPool.getLargestPoolSize());//最大達到過的池大小
info.put("maximumPoolSize", threadPool.getMaximumPoolSize());//設置的最大池大小
info.put("completedTaskCount", threadPool.getCompletedTaskCount());//總完成任務數
return info;
}
@Override
public void contribute(Info.Builder builder) {
builder.withDetail("demoThreadPool", threadPoolInfo(ThreadPoolProvider.getDemoThreadPool()));
builder.withDetail("ioThreadPool", threadPoolInfo(ThreadPoolProvider.getIOThreadPool()));
}
}
直接訪問http://localhost:8080/actuator/info
如果開啓jmx,還可以使用jconsole來查看線程池的狀態信息:
#開啓 JMX
spring.jmx.enabled=true
打開jconcole界面之後,進入MBean這個tab,可以在EndPoint下的Info操作這裏看到我們的Bean信息。
不過,除了jconsole之外,我們可以把JMX協議轉爲http協議,這裏引入jolokia:
<dependency>
<groupId>org.jolokia</groupId>
<artifactId>jolokia-core</artifactId>
</dependency>
重啓後訪問:http://localhost:8080/actuator/jolokia/exec/org.springframework.boot:type=Endpoint,name=Info/info
監控延伸
通過Micrometer+promethues+grafana的組合也可以進行一些生產級別的實踐。