Micrometer 自定义 metrics

Micrometer 提供了基于 Java的 monitor facade，其与 springboot 应用和 prometheus 的集成方式如下图展示

上图中展示得很清楚，应用通过Micrometer采集和暴露监控端点给prometheus，prometheus通过pull模式来采集监控时序数据信息。之后作为数据源提供给grafana进行展示。

Micrometer支持的度量方式及在springboot中的应用示例

Counter
Counter(计数器)简单理解就是一种只增不减的计数器。它通常用于记录服务的请求数量、完成的任务数量、错误的发生数量等等。

package com.olive.producter.monitor; import org.springframework.stereotype.Service; import io.micrometer.core.instrument.Counter; import io.micrometer.core.instrument.Metrics; @Service("collectorService") public class CollectorService { static final Counter userCounter = Metrics.counter("user.counter.total", "services", "demo"); public void processCollectResult() throws InterruptedException { while (true) { userCounter.increment(1D); } } }

Gauge
Gauge(仪表)是一个表示单个数值的度量，它可以表示任意地上下移动的数值测量。Gauge通常用于变动的测量值，如当前的内存使用情况，同时也可以测量上下移动的”计数”，比如队列中的消息数量。

package com.olive.producter.monitor; import java.util.ArrayList; import java.util.List; import java.util.concurrent.atomic.AtomicInteger; import org.springframework.stereotype.Component; import io.micrometer.core.instrument.Gauge; import io.micrometer.core.instrument.ImmutableTag; import io.micrometer.core.instrument.Metrics; import io.micrometer.core.instrument.Tag; import io.micrometer.core.instrument.simple.SimpleMeterRegistry; @Component("passCaseMetric") public class PassCaseMetric { List 
   
     init() { ArrayList 
    
      list = new ArrayList() { }; list.add(new ImmutableTag("service", "demo")); return list; } AtomicInteger atomicInteger = new AtomicInteger(0); Gauge passCaseGuage = Gauge.builder("pass.cases.guage", atomicInteger, AtomicInteger::get).tag("service", "demo") .description("pass cases guage of demo").register(new SimpleMeterRegistry()); AtomicInteger passCases = Metrics.gauge("pass.cases.guage.value", init(), atomicInteger); public void handleMetrics() { while (true) { if (System.currentTimeMillis() % 2 == 0) { passCases.addAndGet(100); System.out.println("ADD + " + passCaseGuage.measure() + " : " + passCases); } else { int val = passCases.addAndGet(-100); if (val < 0) { passCases.set(1); } System.out.println("DECR - " + passCaseGuage.measure() + " : " + passCases); } } } } 
     
   

增加一个controller，触发他们：

package com.olive.producter.web; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import com.olive.producter.monitor.CollectorService; import com.olive.producter.monitor.PassCaseMetric; @RestController @RequestMapping("/monitor") public class MonitorController { @Autowired CollectorService collectorService; @Autowired PassCaseMetric passCaseMetric; @RequestMapping(value = "/counter", method = RequestMethod.GET) public String counter() throws InterruptedException { collectorService.processCollectResult(); return "+1"; } @RequestMapping(value = "/gauge", method = RequestMethod.GET) public String gauge() throws InterruptedException { passCaseMetric.handleMetrics(); return "+gauge"; } }

这里使用了一个true的循环用来展示不断更新的效果。

同样的可以在grafana中看到监控展示信息

Timer
Timer(计时器)同时测量一个特定的代码逻辑块的调用(执行)速度和它的时间分布。简单来说，就是在调用结束的时间点记录整个调用块执行的总时间，适用于测量短时间执行的事件的耗时分布，例如消息队列消息的消费速率。

@Test public void testTimerSample() Timer timer = Timer.builder("timer") .tag("timer", "timersample") .description("timer sample test.") .register(new SimpleMeterRegistry()); for(int i=0; i<2; i++) { timer.record(() -> { try { TimeUnit.SECONDS.sleep(2); }catch (InterruptedException e){ } }); } System.out.println(timer.count()); System.out.println(timer.measure()); System.out.println(timer.totalTime(TimeUnit.SECONDS)); System.out.println(timer.mean(TimeUnit.SECONDS)); System.out.println(timer.max(TimeUnit.SECONDS)); }

响应数据

2 [Measurement{statistic='COUNT', value=2.0}, Measurement{statistic='TOTAL_TIME', value=4.00}, Measurement{statistic='MAX', value=2.00}] 4.00 2.00 2.00

Summary
Summary(摘要)用于跟踪事件的分布。它类似于一个计时器，但更一般的情况是，它的大小并不一定是一段时间的测量值。在Micrometer中，对应的类是DistributionSummary，它的用法有点像Timer，但是记录的值是需要直接指定，而不是通过测量一个任务的执行时间。

@Test public void testSummary() DistributionSummary summary = DistributionSummary.builder("summary") .tag("summary", "summarySample") .description("summary sample test") .register(new SimpleMeterRegistry()); summary.record(2D); summary.record(3D); summary.record(4D); System.out.println(summary.count()); System.out.println(summary.measure()); System.out.println(summary.max()); System.out.println(summary.mean()); System.out.println(summary.totalAmount()); }

响应数据：

3 [Measurement{statistic='COUNT', value=3.0}, Measurement{statistic='TOTAL', value=9.0}, Measurement{statistic='MAX', value=4.0}] 4.0 3.0 9.0

序

本文主要研究下如何使用自定义Micrometer的metrics

实例

DemoMetrics

public class DemoMetrics implements MeterBinder { AtomicInteger count = new AtomicInteger(0); @Override public void bindTo(MeterRegistry meterRegistry) { Gauge.builder("demo.count", count, c -> c.incrementAndGet()) .tags("host", "localhost") .description("demo of custom meter binder") .register(meterRegistry); } }

这里实现了MeterBinder接口的bindTo方法，将要采集的指标注册到MeterRegistry

注册

• 原始方式

new DemoMetrics().bindTo(registry);

• springboot autoconfigure

@Bean public DemoMetrics demoMetrics(){ return new DemoMetrics(); }

在springboot只要标注下bean，注入到spring容器后，springboot会自动注册到registry。springboot已经帮你初始化了包括UptimeMetrics等一系列metrics。详见源码解析部分。

验证

curl -i http://localhost:8080/actuator/metrics/demo.count

返回实例

{ "name": "demo.count", "measurements": [ { "statistic": "VALUE", "value": 6 } ], "availableTags": [ { "tag": "host", "values": [ "localhost" ] } ] }

源码解析

MetricsAutoConfiguration

spring-boot-actuator-autoconfigure-2.0.0.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/metrics/MetricsAutoConfiguration.java

@Configuration @ConditionalOnClass(Timed.class) @EnableConfigurationProperties(MetricsProperties.class) @AutoConfigureBefore(CompositeMeterRegistryAutoConfiguration.class) public class MetricsAutoConfiguration { @Bean @ConditionalOnMissingBean public Clock micrometerClock() { return Clock.SYSTEM; } @Bean public static MeterRegistryPostProcessor meterRegistryPostProcessor( ApplicationContext context) { return new MeterRegistryPostProcessor(context); } @Bean @Order(0) public PropertiesMeterFilter propertiesMeterFilter(MetricsProperties properties) { return new PropertiesMeterFilter(properties); } @Configuration @ConditionalOnProperty(value = "management.metrics.binders.jvm.enabled", matchIfMissing = true) static class JvmMeterBindersConfiguration { @Bean @ConditionalOnMissingBean public JvmGcMetrics jvmGcMetrics() { return new JvmGcMetrics(); } @Bean @ConditionalOnMissingBean public JvmMemoryMetrics jvmMemoryMetrics() { return new JvmMemoryMetrics(); } @Bean @ConditionalOnMissingBean public JvmThreadMetrics jvmThreadMetrics() { return new JvmThreadMetrics(); } @Bean @ConditionalOnMissingBean public ClassLoaderMetrics classLoaderMetrics() { return new ClassLoaderMetrics(); } } @Configuration static class MeterBindersConfiguration { @Bean @ConditionalOnClass(name = { "ch.qos.logback.classic.LoggerContext", "org.slf4j.LoggerFactory" }) @Conditional(LogbackLoggingCondition.class) @ConditionalOnMissingBean(LogbackMetrics.class) @ConditionalOnProperty(value = "management.metrics.binders.logback.enabled", matchIfMissing = true) public LogbackMetrics logbackMetrics() { return new LogbackMetrics(); } @Bean @ConditionalOnProperty(value = "management.metrics.binders.uptime.enabled", matchIfMissing = true) @ConditionalOnMissingBean public UptimeMetrics uptimeMetrics() { return new UptimeMetrics(); } @Bean @ConditionalOnProperty(value = "management.metrics.binders.processor.enabled", matchIfMissing = true) @ConditionalOnMissingBean public ProcessorMetrics processorMetrics() { return new ProcessorMetrics(); } @Bean @ConditionalOnProperty(name = "management.metrics.binders.files.enabled", matchIfMissing = true) @ConditionalOnMissingBean public FileDescriptorMetrics fileDescriptorMetrics() { return new FileDescriptorMetrics(); } } static class LogbackLoggingCondition extends SpringBootCondition { @Override public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) { ILoggerFactory loggerFactory = LoggerFactory.getILoggerFactory(); ConditionMessage.Builder message = ConditionMessage .forCondition("LogbackLoggingCondition"); if (loggerFactory instanceof LoggerContext) { return ConditionOutcome.match( message.because("ILoggerFactory is a Logback LoggerContext")); } return ConditionOutcome .noMatch(message.because("ILoggerFactory is an instance of " + loggerFactory.getClass().getCanonicalName())); } } }

可以看到这里注册了好多metrics，比如UptimeMetrics，JvmGcMetrics，ProcessorMetrics，FileDescriptorMetrics等

这里重点看使用@Bean标注了MeterRegistryPostProcessor

MeterRegistryPostProcessor

spring-boot-actuator-autoconfigure-2.0.0.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryPostProcessor.java

class MeterRegistryPostProcessor implements BeanPostProcessor { private final ApplicationContext context; private volatile MeterRegistryConfigurer configurer; MeterRegistryPostProcessor(ApplicationContext context) { this.context = context; } @Override public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { if (bean instanceof MeterRegistry) { getConfigurer().configure((MeterRegistry) bean); } return bean; } @SuppressWarnings("unchecked") private MeterRegistryConfigurer getConfigurer() { if (this.configurer == null) { this.configurer = new MeterRegistryConfigurer(beansOfType(MeterBinder.class), beansOfType(MeterFilter.class), (Collection 
   
     >) (Object) beansOfType( MeterRegistryCustomizer.class), this.context.getBean(MetricsProperties.class).isUseGlobalRegistry()); } return this.configurer; } private 
    
      Collection 
     
       beansOfType(Class 
      
        type) { return this.context.getBeansOfType(type).values(); } } 
       
      
     
   

可以看到这里new了一个MeterRegistryConfigurer，重点注意这里使用beansOfType(MeterBinder.class)方法的返回值给其构造器

MeterRegistryConfigurer

spring-boot-actuator-autoconfigure-2.0.0.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryConfigurer.java

class MeterRegistryConfigurer { private final Collection 
   
     > customizers; private final Collection 
    
      filters; private final Collection 
     
       binders; private final boolean addToGlobalRegistry; MeterRegistryConfigurer(Collection 
      
        binders, Collection 
       
         filters, Collection 
        
          > customizers, boolean addToGlobalRegistry) { this.binders = (binders != null ? binders : Collections.emptyList()); this.filters = (filters != null ? filters : Collections.emptyList()); this.customizers = (customizers != null ? customizers : Collections.emptyList()); this.addToGlobalRegistry = addToGlobalRegistry; } void configure(MeterRegistry registry) { if (registry instanceof CompositeMeterRegistry) { return; } // Customizers must be applied before binders, as they may add custom // tags or alter timer or summary configuration. customize(registry); addFilters(registry); addBinders(registry); if (this.addToGlobalRegistry && registry != Metrics.globalRegistry) { Metrics.addRegistry(registry); } } @SuppressWarnings("unchecked") private void customize(MeterRegistry registry) { LambdaSafe.callbacks(MeterRegistryCustomizer.class, this.customizers, registry) .withLogger(MeterRegistryConfigurer.class) .invoke((customizer) -> customizer.customize(registry)); } private void addFilters(MeterRegistry registry) { this.filters.forEach(registry.config()::meterFilter); } private void addBinders(MeterRegistry registry) { this.binders.forEach((binder) -> binder.bindTo(registry)); } } 
         
        
       
      
     
   

可以看到configure方法里头调用了addBinders，也就是把托管给spring容器的MeterBinder实例bindTo到meterRegistry

小结

springboot2 引入的 Micrometer，自定义metrics只需要实现MeterBinder接口，然后托管给spring即可，springboot的autoconfigure帮你自动注册到meterRegistry。

source: //www.cnblogs.com/duanxz/p/10179946.html

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