Micrometer源码分析-天涯论坛 - Powered by Discuz! Archiver

tw4ld6 发表于 2024-10-10 17:08:30

Micrometer源码分析

<h1 style="color: black; text-align: left; margin-bottom: 10px;">前言</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">好久没输出了，<span style="color: black;">近期</span>比较忙，<span style="color: black;">1星期</span>把一个季度的东西干完才有机会输出。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">倘若</span>编码速度非常快（质量<span style="color: black;">亦</span>非常高），超出一个极限（超出其他所有职能<span style="color: black;">分部</span>的速度），<span style="color: black;">那样</span>不可能有人会占用你的时间。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">就像Integer.MAX_VALUE+1，超出极限了<span style="color: black;">便是</span>负数。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">本章基于springboot3.0.7分析micrometer1.10.7<span style="color: black;">关联</span>源码。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">本章<strong style="color: blue;">不会</strong><span style="color: black;">太多</span>关注：</p>prometheus客户端<span style="color: black;">怎样</span><span style="color: black;">运用</span>PromQLspringboot3放弃sleuth，转而<span style="color: black;">运用</span>micrometer-tracingpush模式收集metrics<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">本章<strong style="color: blue;">仅限于</strong>分析micrometer：</p>以micrometer接入prometheus的实现为抓手，<span style="color: black;">瞧瞧</span><span style="color: black;">怎样</span><span style="color: black;">创立</span>一套metrics模型pull模式收集metricsmicrometer做业务埋点，api<span style="color: black;">怎样</span><span style="color: black;">运用</span>更<span style="color: black;">恰当</span>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">从SpringBoot入手</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">其实<span style="color: black;">通常</span><span style="color: black;">状况</span>下，我都不太会看和Spring集成<span style="color: black;">关联</span>的东西，除了<span style="color: black;">有些</span>脱离Spring<span style="color: black;">没法</span>（或不会去<span style="color: black;">选取</span>）单独<span style="color: black;">运用</span>的框架，<span style="color: black;">例如</span>Seata。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">这儿</span>看一下Micrometer有<span style="color: black;">那些</span>核心的Bean，好找入口分析。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">通常</span><span style="color: black;">状况</span>下<span style="color: black;">不必</span>看Spring部分，无非是怎么去new一个对象，无论你用什么看起来<span style="color: black;">高挑</span>上的<span style="color: black;">办法</span>，本质<span style="color: black;">便是</span>这个。</p>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">PrometheusMetricsExportAutoConfiguration</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Properties配置类PrometheusConfig（micrometer<span style="color: black;">供给</span>）：</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/fe10493df6a342b7a51c5c7482a44949~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=1FU3%2FbILhvjMNcnHItJKm8U4tHM%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">PrometheusMeterRegistry</strong>（micrometer<span style="color: black;">供给</span>）：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">核心类，MeterRegistry实现，<span style="color: black;">保留</span>所有Meter，micrometer与prometheus集成</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/00e9b86dce334d99b3ab6700d6c7a57d~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=qN6cw8OgTtWGCadDiQUtMubhRpM%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">CollectorRegistry（prometheus<span style="color: black;">供给</span>）：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">prometheus收集metrics的api</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/494ff4d9790d42e6a7633dad5c0dcd17~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=9JtmB6EMQzmHtpoXHg4zNQZ81bk%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">DefaultExemplarSampler（prometheus<span style="color: black;">供给</span>）：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">prometheus<span style="color: black;">针对</span>Exemplar的支持，metrics<span style="color: black;">相关</span>trace</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8193989d806b4b6ead3b1a86e5b13c2e~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=JuOKrMigzngaE%2B7A2r%2BgNiNwveo%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">PrometheusScrapeEndpoint（springboot<span style="color: black;">供给</span>）：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">暴露/actuator/prometheus端点给prometheus拉metrics</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/1e2479755e5549beaac64d90c3438283~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=8MBlb39tXmrdoGmb2KV0v4uI6Pg%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">MetricsAutoConfiguration</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Clock（micrometer<span style="color: black;">供给</span>）：时钟，用于获取时间，<span style="color: black;">便是</span>System.currentTimeMillis。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8db89eff74364e46b38ab904e31a8163~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=2Bpw3EAZh%2F9rlhXqCL41umPqCnw%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">MeterRegistryPostProcessor（springboot<span style="color: black;">供给</span>）：有两个<span style="color: black;">功效</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">1）<span style="color: black;">针对</span>MeterRegistry类型的Bean做<span style="color: black;">有些</span>全局配置处理，<span style="color: black;">例如</span>加入全局MeterFilter，做Meter过滤；</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">2）<span style="color: black;">针对</span>MeterBinder类型的Bean，主动触发bind<span style="color: black;">办法</span>注册meter到MeterRegistry；</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ccf448a10bd54d7791fb9a5fd64241f4~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=c4flXnYUx666uecvJUb4HZHI4DQ%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">PropertiesMeterFilter（springboot<span style="color: black;">供给</span>）：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">基于management.metrics配置项的MeterFilter；</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/f7a539e0eb8b4aedb6371c60653bc44b~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=JaFS%2FhxBXT%2Bqk0v%2Bf3%2Fs72%2Bz5k0%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Mircometer模型</h1>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Meter</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Meter聚合了一组度量（Measurement），用Id<span style="color: black;">表率</span>这组度量。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">每次measure<span style="color: black;">办法</span>返回都是相同数量、相同<span style="color: black;">次序</span>的一组瞬时value。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/f7b166b0c61d4cf2838dfa8981787979~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=oCDAO0t3sCqUNtSrXrsu4GfMf3U%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Id</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Id<span style="color: black;">重点</span>由三部分<span style="color: black;">构成</span>：name-meter名，tags-meter标签集合，type-meter的类型。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Id#hashCode：<span style="color: black;">然则</span>Id的<span style="color: black;">独一</span>性，仅由name和tag决定。（equals代码不贴了，太长）</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/51cb8af29187492bb2f046dfd4bbfa87~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=CysESgMVlYUmdF1Jo4ECcia9OSw%3D" style="width: 50%; margin-bottom: 20px;"></div>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/3c3d2897c14841f5bfb333fdfa8a33b9~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=CQUIhraUyxKKH5xNCXacz7Xu2OU%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Tag</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Tags由多个Tag<span style="color: black;">构成</span>；而Tag由一对kv<span style="color: black;">构成</span>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">当kv相<span style="color: black;">同期</span>，Tag相同；当所有Tag相同，Tags相同。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/65e531a464b649c3bc1c927ed89dee31~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=uDzXzdO%2FJwpjPVz29j7gNaxJqew%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Tag#hasCode：</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8b8dbaab46fd4d5bba6be54b9da290ea~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=j%2BslFRiDk7BSz3BCPuDtz9cuFlk%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Measurement</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">度量<span style="color: black;">包括</span>两个属性：</p>DoubleSupplier：一个返回double的supplier函数；Statistic：枚举，<span style="color: black;">针对</span>一个度量的描述；<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/eca31127be944702a65a3e024ed781b9~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=CUzR4EmyP7mWhF%2FDiqAQ3CcVwtw%3D" style="width: 50%; margin-bottom: 20px;"></div>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8a8ba78d7bdd41fdb9c796b17430c2b6~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=L00mnyRbCWbcIgaee8NxxkoH4OA%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">转换Prometheus格式</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">例如</span>jvm内存<span style="color: black;">运用</span><span style="color: black;">状况</span>，暴露给prometheus的数据格式如下：</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/e81cab81c9894411aed550b702998753~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=%2Fn1ARBt5rbAqlZm7WKxGvQLtV1M%3D" style="width: 50%; margin-bottom: 20px;"></div>jvm_memory_used是Id.name，bytes是单位；{application="sb3-app",area="nonheap",id="Compressed Class Space",}是Tags；<span style="color: black;">这儿</span>一行是一个Measurement度量，这个Meter<span style="color: black;">仅有</span>一个度量；<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">例如</span>某个端点的http请求，暴露给prometheus的数据格式如下：</p>ini复制代码http_server_requests_seconds_count{application="sb3-app",error="none",exception="none",method="GET",outcome="SUCCESS",status="200",uri="/metric",} 2.0
http_server_requests_seconds_sum{application="sb3-app",error="none",exception="none",method="GET",outcome="SUCCESS",status="200",uri="/metric",} 0.006369008
http_server_requests_seconds_max{application="sb3-app",error="none",exception="none",method="GET",outcome="SUCCESS",status="200",uri="/metric",} 0.004348599
http_server_requests是Id.name，seconds是单位；{...uri="/metric",}是Tags；一个端点的http请求（一个Id）有3个Measurement度量，count是请求总数，sum是请求总时长，max是请求最大时长；<h1 style="color: black; text-align: left; margin-bottom: 10px;">MeterRegistry</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">一个抽象类，内存中存储Meter。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/bd5fad778044419781e03c929d92ed66~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=bGqBTSl9TNqU0V2hNaK0MDx5KTo%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">MeterRegistry<span style="color: black;">供给</span><span style="color: black;">有些</span>方便<span style="color: black;">运用</span>的注册Meter<span style="color: black;">办法</span>，<span style="color: black;">例如</span>注册一个Counter类型的meter。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8182ba9ae05c4137839ba82a0f66a3f7~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=IDnsx6gUyBjF0apIwoJx%2FvuzLlg%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">为此，子类需要实现<span style="color: black;">有些</span>构建Meter的<span style="color: black;">办法</span>，<span style="color: black;">例如</span>构建一个Counter。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/6b13c1f4c32a493391a46d59278b68f9~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=s5aXczXA%2BSg9BO9tvgzeJUsCxpg%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">MeterRegistry<span style="color: black;">供给</span>注册Meter的骨架<span style="color: black;">办法</span>getOrCreateMeter流程如下：</p>MeterFilter#accept过滤Meter.IdMeterFilter#configure<span style="color: black;">按照</span>Meter.Id二次处理DistributionStatisticConfigbuilder#apply执行用户回调构建Meter同义meter注册meter注册Listener<span style="color: black;">通告</span>注册mter<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/d74b83ed8490492ea39361b64a70ec3d~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=QKMrhIv1XgUsA4DDaTxRerwzLok%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">MeterBinder</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">除了直接调用MeterRegistry<span style="color: black;">能够</span>注册Meter之外。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">部分Metrics会实现MeterBinder接口，将Meter注册到MeterRegistry。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/19aba13c03954b58b011c12b379879c6~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=URGtcasabHT5Vn%2F6Lx5LQqaP%2BSQ%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在SpringBoot中，MeterRegistryPostProcessor会来触发所有MeterBinder的注册动作。</p>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">几种Meter</h1>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Counter</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Counter只会返回一个double类型的度量，是一个只增不减的计数器。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/65bc500d10ca46ef99625ec4f64ea34c~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=BuXjtMvkRbl02273crQJjYAshsI%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">micrometer<span style="color: black;">针对</span>Prometheus的实现是<strong style="color: blue;">PrometheusCounter</strong>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">PrometheusCounter除了一个DoubleAddr计数器之外，还有一个<strong style="color: blue;">Exemplar</strong>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ffea56564bda45978c14f3580167887f~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=LbJAIrsQL3IiK8bC7vrTSBycpgw%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">每次更新计数器，还会更新Exemplar。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/5d771b4c981748068a392e84ed2990f0~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=QEJtzco5c9YBgMz1fp0XqMw9mWE%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">这个<strong style="color: blue;">Exemplar的<span style="color: black;">功效</span><span style="color: black;">便是</span><span style="color: black;">相关</span>metric和trace</strong>，见OpenMetrics。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在客户端侧，<span style="color: black;">倘若</span>加入tracing<span style="color: black;">关联</span>组件，就能<span style="color: black;">运用</span>Exemplar，见SpringBoot+micrometer-tracing。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在prometheus侧，需要开启exemplar-storage特性，见Prometheus+exemplars-storage。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在grafana侧，<span style="color: black;">能够</span><span style="color: black;">经过</span>metric拿到Exemplar，而Exemplar中<span style="color: black;">包括</span>trace_id，方便定位问题。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/a20608ec04af4cba9b11b7e465ac33e5~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=8vZjwqTIP%2FjqXnWh7E4MwhBqYgI%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">需要<span style="color: black;">重视</span>的是，<span style="color: black;">日前</span>Exemplar仅支持prometheus，<span style="color: black;">因此</span>这两个模型都是prometheus客户端<span style="color: black;">供给</span>的。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/5bbd6bdab4ac445d8069b3d51aabb7d4~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=oUoBkT%2B8oDfmoLhYzg1x7Pq20lc%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">PrometheusCounter#updateExemplar：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">每次increment都会调用CounterExemplarSampler采集一个Exemplar，替换Counter中的Exemplar。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">因此</span>promethues配置scrape_interval=15s抓取一次，<span style="color: black;">那样</span>只会抓到<span style="color: black;">近期</span>一次Counter记录到的trace。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/3a71925713434aebaf4d1a048fac3322~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=BxUvT8m6JepNQReEYeV9N%2BVMECU%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">DefaultExemplarSampler#doSample：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">当满足下面两个<span style="color: black;">要求</span>的<span style="color: black;">状况</span>下，才会采集新的Exemplar，Exemplar<span style="color: black;">包括</span>当前线程中的trace信息</p><span style="color: black;">倘若</span>trace要采集（isSampled=true）距离上次采样时间超过一<span style="color: black;">按时</span>间（minRetentionIntervalMs=7109ms）<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">不满足<span style="color: black;">以上</span><span style="color: black;">要求</span>，PrometheusCounter中的Exemplar不会更新。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/9f4461803934442a953d09f868823f09~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=3VLYojTONX%2FPCSx9VxpaotBV86g%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Gauge</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">Gauge</strong>只会返回一个double类型的度量，可增可减。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/30194b84a4c5492eaa9baef4109b34f1~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=LX3Ol%2F82uKdLtoxi6o1xWaN4lEU%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">micrometer<span style="color: black;">针对</span>Prometheus<span style="color: black;">无</span>特殊实现，<span style="color: black;">运用</span><strong style="color: blue;">DefaultGauge</strong>。</p>value：一个Function函数，获取double类型度量，不像Counter<span style="color: black;">通常</span>自己就能<span style="color: black;">守护</span>一个计数器；ref：<span style="color: black;">做为</span>Function入参对象，一个弱引用，<span style="color: black;">通常</span><span style="color: black;">来讲</span>ref引用的对象是一个长生命周期对象；<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">重视</span>Gauge<span style="color: black;">没法</span><span style="color: black;">供给</span>Exemplar，即<span style="color: black;">没法</span>关联trace。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/9d0fd84bdd2642469b6eafcd4e91c62a~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=RPAOLJ2FIov5ClvItd4VA4o3sIE%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Timer</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Timer用于跟踪<span style="color: black;">海量</span><span style="color: black;">短期</span>运行事件的计时器，<span style="color: black;">通常</span>这些事件在一分钟以内，<span style="color: black;">例如</span>http请求。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/1846893ffac64cb7857ab0aea5071389~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=nfn%2BT15wmk3zhZURzUuCKnGp4TU%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Timer有三个度量：count-总数、totalTime-总耗时、max-最长耗时。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/e709a45bc5b14827978ccabaf213a700~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=Eb5ZL%2BYpGg2%2F9p%2FCIkrOflSYOhs%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Timer用于统计事件时长，埋点方式有多种。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">例如</span>，在事件<span style="color: black;">起始</span>需要Timer#start拿到一个Timer.Sample。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/cf2935d0df3c4b6282beef7ce81c23ae~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=Wd8LuZf2bGBHXQCrhy1deMkLr20%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在事件结束需要Timer.Sample#stop，调用Timer实例的record<span style="color: black;">办法</span>记录事件耗时。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/dfa59fd541a4467a84a68550c83762b7~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=d7dOCIyndgyL6WysIntcj%2F3QW8g%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">又<span style="color: black;">例如</span>，Timer#record直接记录耗时，需要子类实现。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/f1d05b6404b04bfd8308977b6facf187~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=7ipAf24Z6KocGVuCq2Wabilw%2FkM%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">AbstractTimer实现了record<span style="color: black;">规律</span>，忽略Histogram和IntervalEstimator，子类需要实现recordNonNegative。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/afd703c9e9a94598a0167215e3da94bc~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=GBgJagmaY7gn58izB8Ii5uIpIq0%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">PrometheusTimer#recordNonNegative：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">三个度量计算，重点关注一下TimeWindowMax。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">重视</span>，单纯PrometheusTimer并不支持Exemplar，Exemplar依<span style="color: black;">附着</span>Histogram<span style="color: black;">运用</span>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/28de6862179e472cbefc1588a5e7cac9~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=8mBBTpPhctV2ccDle0gSv%2BNNib0%3D" style="width: 50%; margin-bottom: 20px;"></div>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/819cf42523cf4dfea1544fd8115d7c43~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=tvdV1318S3ik3QxKabPvTme1RH0%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">TimeWindowMax属性如下，<span style="color: black;">重点</span>是<span style="color: black;">经过</span>一个环形数组，<span style="color: black;">每一个</span>数组元素存储1分钟内的最大时长。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/f4aa0d56dbde431bbbb04d88e84e3fb8~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=0a%2BSr087g48tCqQb5y6sLZ7OX64%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">TimeWindowMax的滚动间隔时长和环形数组容量，都取自于DistributionStatisticConfig。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/df6d5a59fa394a96a873c3c4fc47ab7e~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=i2ES8IGddu8KZK%2FVy8dJ%2BNKjbro%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在记录最值的时候，先滚动，<span style="color: black;">而后</span>用采样值更新所有桶中的最值。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/577481ad1d654a00bcdefed54cfd9692~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=1nmA896qEvyAK11jlzuv9lEJiX0%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">滚动<span style="color: black;">办法</span>如下，<span style="color: black;">初期</span>版本（1.6.11之前）有bug（issue=2647），可能<span style="color: black;">没法</span>采集到正确的最值。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">TimeWindowMax#rotate：超过一分钟未滚动，才进行滚动。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/5f9eff29eb0143b892dfbd7b30753373~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=rFsNo43%2Fv55jwO%2B7H3kaYDkKT58%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">TimeWindowMax#rotate：第<span style="color: black;">一起</span>滚动<span style="color: black;">规律</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">这个是issue=2647新增的<span style="color: black;">规律</span>，<span style="color: black;">倘若</span>超过3分钟未滚动，清空所有桶，并更新上次滚动时间。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/88677af195224b50a4d7f98e50a35643~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=JCjcdSEDl2BIrM%2Fuj4FDQjYE%2BqA%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">TimeWindowMax#rotate：第二块滚动<span style="color: black;">规律</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">初期</span>版本<span style="color: black;">仅有</span>这<span style="color: black;">一起</span>滚动<span style="color: black;">规律</span>，问题在于timer<span style="color: black;">长时间</span>未被调用，lastRotateTimestampMillis上次滚动时间<span style="color: black;">没法</span>正确更新。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8806993ea3914137a92f463373187e65~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=z67ZujlJmKi2G7J8oDXZ%2BOZoZWg%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">TimeWindowMax#poll：获取最值的<span style="color: black;">办法</span>，先尝试滚动，<span style="color: black;">而后</span>获取当前桶中的最值。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">注：滚动和获取最值做了同步synchronized。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/f5ad14fd582b40ec83bc120b2a03aef4~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=NZkEIxqA1e3dCIGXJxKiCcHjVao%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">以官方测试用例为例，<span style="color: black;">规律</span>如下。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">需要理解的是，TimeWindowMax最值并不是1分钟内的最值，是3分钟内的最值。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/39341ffb69ea4790ba7cefc85aea9397~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=pI8PhDjFPNyWgFOKq6oeprj1%2Bb4%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">官方<span style="color: black;">叫作</span>为：基于可配置环形缓冲区的分布衰减最大值。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/a2d0127fce174cb89f079a929fecfd8a~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=soHDwyA%2FcBlM54jvPJExSoCR71c%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">LongTaskTimer</h1>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/1b81c2674d2b4e248eb5771eb32a29c4~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=yFF8xMLGcIN7WPKQ2xRQCABFkQc%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">LongTaskTimer和Timer完全<span style="color: black;">区别</span>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">LongTaskTimer用于度量<strong style="color: blue;">正在执行的任务数量</strong>和<strong style="color: blue;">这些任务<span style="color: black;">已然</span>执行的时长</strong>，重点<span style="color: black;">便是</span>in-flight。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">LongTaskTimer<span style="color: black;">亦</span>支持Histogram。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/3086a33bb42448b8ae97c8d7e723dc6e~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=4TKqlbJmxLufGsTVLj5Oydg6Uco%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">举个例子：</p>typescript复制代码@RestController
public class OrderMetrics implements MeterBinder {

private LongTaskTimer longTaskTimer;

@Override
public void bindTo(MeterRegistry meterRegistry) {
longTaskTimer = LongTaskTimer.builder("order.long.task")
.publishPercentileHistogram(true)
.publishPercentiles(0.5, 0.95)
.minimumExpectedValue(Duration.ofSeconds(10))
.maximumExpectedValue(Duration.ofSeconds(20))
.register(meterRegistry);
}

@GetMapping("/order/longtask")
public String longtask() {
EXECUTOR.submit(() -> {
LongTaskTimer.Sample sample = longTaskTimer.start();
int time = RANDOM.nextInt(10, 20);
try {
TimeUnit.SECONDS.sleep(time);
} catch (InterruptedException e) {
sample.stop();
return;
}
sample.stop();
});
return "success";
}
}<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">虽然历史曾经有过LongTaskTimer采集数据（从histogram数据<span style="color: black;">能够</span>看到）。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">然则</span>active_count、duration_sum、max都为0，<span style="color: black;">由于</span>LongTaskTimer的度量仅针对in-flight数据，当所有任务执行完毕，这些度量都会变成0。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/5c552836e4e04181a6717afc00f60563~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=PfP2e7nr%2BYopjtQJAA%2BaBH%2FqdRU%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Prometheus接入的实现是<strong style="color: blue;">CumulativeHistogramLongTaskTimer</strong>，<span style="color: black;">仅有</span>Histogram<span style="color: black;">关联</span>的takeSnapshot<span style="color: black;">办法</span>有点特殊，<span style="color: black;">规律</span>都走<strong style="color: blue;">DefaultLongTaskTimer</strong>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Histogram部分放在后面统一看，<span style="color: black;">这儿</span>Histogram的特点和其他Prometheus接入的实现类似，桶计数要<span style="color: black;">运用</span>累积数量。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ffa87acd61024ff58f9539b0f82fbbd4~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=ROu8D1nRuxT3aVO0f40wyN%2F6pBM%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">DefaultLongTaskTimer#start：创建Sample实例，放入activeTasks集合存储。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/12f6f8ac05594342964e1ca3c79d39fb~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=tOcPZZefyhEtYF5QTp1p44WetAM%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">DefaultLongTaskTimer.SampleImpl#stop：从activeTasks集合移除Sample。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/c4779a01d6114027a3bd03474b71b983~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=FwdnuFeiZoLtyitEAh3fyuwAfQw%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">获取度量，duration统计所有正在执行任务的累计时长，activeTasks统计正在执行的任务数量。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/276135dcd9924023b564ea165bbdd32a~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=I%2FNnDYtugK1VnpXFe29L2pvw%2B4k%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">max统计此时执行最长的时长。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/b8d054905c2c43d383bd84b95b032a55~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=Y2jNLopV12UdU8EWZuksTMIExsY%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">DistributionSummary</h1>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/204ac9dfeefa4c428280b45fd3bd2652~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=Ad2vo4TAHYd4BBu9kMIXb5Llb70%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在micrometer侧，DistributionSummary和Timer几乎<span style="color: black;">无</span>区别，仅仅是单位上的区别。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Timer是时间，而DistributionSummary是任意值。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">A distribution summary tracks the distribution of events. It is similar to a timer structurally, but records values that do not represent a unit of time. For example, you could use a distribution summary to measure the payload sizes of requests hitting a server.</p>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Histogram</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Histogram不属于Meter，依<span style="color: black;">附着</span>Timer和DistributionSummary。</p>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">案例</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">默认<span style="color: black;">状况</span>下，普通的Timer不会开启Histogram，案例<span style="color: black;">经过</span>Timer统计订单详情的P50和P95。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">注：<span style="color: black;">运用</span>micrometer<span style="color: black;">供给</span>的TimedAspect加Timed注解<span style="color: black;">亦</span><span style="color: black;">能够</span>，api更灵活。</p>typescript复制代码@RestController
public class OrderMetrics implements MeterBinder {
private Timer orderDetailTimer;
@Override
public void bindTo(MeterRegistry meterRegistry) {
orderDetailTimer = Timer.builder("order.detail")
.publishPercentileHistogram(true)
.publishPercentiles(0.5, 0.95)
// 默认1ms-30s
.minimumExpectedValue(Duration.ofMillis(1))
.maximumExpectedValue(Duration.ofSeconds(5))
.register(meterRegistry);
}
public void orderDetailRecord(long time, TimeUnit unit) {
orderDetailTimer.record(time, unit);
}

@GetMapping("/order/detail")
public String detail() {
log.info("订单详情<span style="color: black;">起始</span>"); // for trace
int time = RANDOM.nextInt(1, 2000);
this.orderDetailRecord(time, TimeUnit.MILLISECONDS);
log.info("订单详情结束"); // for trace
return "success";
}
}<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">暴露给prometheus的数据格式如下：</p>order_detail_seconds_bucket，<span style="color: black;">表率</span>1ms到5s<span style="color: black;">每一个</span>桶中的请求数量，这个数量是依次累计的，第10个桶<span style="color: black;">包括</span>前1-9个桶中所有请求数量的总和，支持Exemplar；order_detail_seconds{quantile}，<span style="color: black;">表率</span>P50和P95对应的值；<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/a91fcee9a5484b80acd5b201e1e11aa7~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=hvBYT8gnXEgb6hAdwssDC1a4U%2F0%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">HistogramSnapshot</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">针对</span>部分Meter，<span style="color: black;">例如</span>Timer和Summary，支持Histogram，会实现takeSnapshot<span style="color: black;">办法</span>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">takeSnapshot返回一个Histogram的快照，不属于Measurement度量。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/0d9130d64ed14d13b43c94be24cee264~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=b8RK5B7a96OWKfKodjSwnD0fSvM%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">HistogramSnapshot</strong>除了传统的count、total、max这种度量之外，还有两个数组：</p><strong style="color: blue;">percentileValues</strong>：分位数对应值，<span style="color: black;">例如</span>案例P50对应值在percentileValues的位置，P95对应值在percentileValues的位置，即案例order_detail_seconds{quantile}<strong style="color: blue;">histogramCounts</strong>：<span style="color: black;">每一个</span>桶中的数量，即案例order_detail_seconds_bucket<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/2101ff3a852f42578616b7917dcc6b75~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=D7jPgHMcCEp5Ri4WkSuaXY7wbIQ%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">PrometheusTimer#takeSnapshot</strong>：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">针对</span>PrometheusTimer<span style="color: black;">来讲</span>，<strong style="color: blue;">桶计数需要走自己的histogram来获取</strong>，而<strong style="color: blue;">分位数值走父类的histogram获取</strong>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">至于<span style="color: black;">为何</span>需要这么<span style="color: black;">繁杂</span>分两个Histogram来获取数据，是<span style="color: black;">由于</span>Prometheus<span style="color: black;">针对</span>桶计数需要完整的数据，而不是滚动的Histogram。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">言外之意，桶计数需要从进程<span style="color: black;">起步</span>到进程停止，完整生命周期内累计的数据；而分位数值是滚动数据。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/5bde9c90ce5f44e6a4c93ffb5f1a4d81~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=GmJgSWcyfpYAhzg2b02YlrlxoMI%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">父类AbstractTimer的Histogram走<strong style="color: blue;">TimeWindowPercentileHistogram</strong>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/d0c21bc7dfd9438d8f57645788fb1b94~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=M8tA1%2BkTBXiWUZp0Hspa2B%2BVftg%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">自己的Histogram走<strong style="color: blue;">PrometheusHistogram</strong>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/bd13831e11d24d2ab006c07f84c7fae4~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=xh7PI1jyLakpv5Cy39rnk1aw%2BiY%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">PrometheusHistogram</strong>底层是micrometer的<strong style="color: blue;">TimeWindowFixedBoundaryHistogram</strong>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/52b21673ae9d4e21baa7989e74671487~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=RCIg1eeqP36hv1crIB2f1Uc58lw%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">全部</span>Histogram<span style="color: black;">触及</span>到的继承关系如下，一点一点来看吧。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/871d9b91f4514387aad908a897e41653~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=covUHzlR8QtHzhqHVxBqyukGW8M%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">Histogram</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Histogram<span style="color: black;">自己</span>具备takeSnapshot能力，<span style="color: black;">因此</span><span style="color: black;">通常</span>Timer和Summary都会委派底层Histogram生成快照。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">除此以外，record<span style="color: black;">办法</span>记录埋点值。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ee9f03e843964faba763ad59a35b0c75~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=5evImrRerFKwkxqynOqGoKPr5sI%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">AbstractTimeWindowHistogram</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">和TimeWindowMax类似，<span style="color: black;">经过</span>一个环形数组存储埋点值。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">只<span style="color: black;">不外</span>数组元素是泛型T，即AbstractTimeWindowHistogram<span style="color: black;">能够</span>理解为<strong style="color: blue;">存储了x个时间窗口内的T</strong>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">相较于TimeWindowMax多了<span style="color: black;">有些</span>Histogram专属的属性，泛型U是一个<strong style="color: blue;">累积Histogram</strong>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">这个累计Histogram大概是啥意思，后面再看。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8c74c279af084b3ea1e0abd2715fca9f~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=U%2BoX9%2Bzu2WIGMR%2F0dFQ0ebhV0IU%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">记录采集值和TimeWindowMax<span style="color: black;">规律</span>类似，recordLong记录bucket需要子类实现。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/74441a1bfddd481e9ac405d792a942e6~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=zDpr9ySAkMInhHpKvCkKS9HGCTQ%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">AbstractTimeWindowHistogram#takeSnapshot：获取HistogramSnapshot的骨架<span style="color: black;">办法</span>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ac64bd45f1384a97b5f2ccc5397a9122~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=huM45jHQSe7KDP4CeW3gzzN9jVA%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">子类需要实现三个抽象<span style="color: black;">办法</span>用于获取HistogramSnapshot：</p>accumulate：累计Histogram，后面再看；valueAtPercentile：获取分位数对应的值，<span style="color: black;">例如</span>P95对应2秒；countAtValue：获取某个桶中的采样总数，<span style="color: black;">例如</span>传入1秒，得到0.5-1秒总共有5个请求；<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/733a7563f9e34ea08c8e9aa48fcfe9ce~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=xBsHveS16RGXstTxaK6hfkwR3Ps%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">TimeWindowPercentileHistogram</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在PrometheusTimer中，仅用于获取分位数值，<span style="color: black;">例如</span>P95=2秒。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">DoubleRecorder</strong>即泛型T，是底层环形数组中的元素，用于记录<span style="color: black;">每一个</span>时间窗口内的采样值；</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">DoubleHistogram</strong>即泛型U，是底层定义的累计Histogram，当takeSnapshot会将当前窗口的采样值T累计到U；</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">这两个类都不是micrometer自己的，是HdrHistogram<span style="color: black;">供给</span>的，<span style="color: black;">无</span>其他任何依赖，当jdk用<span style="color: black;">就可</span>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ed34f599485848c8bde8633bbb5dffa0~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=JbvF14ScA6bnCh11lt5zVHR0%2FTw%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在记录采样值时，调用HdrHistogram记录。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p26-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/f601beb316564de1bfd6bd6005e5ce25~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=eoDXmS7PYiz8K%2BNlOniEp4aRsGk%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在创建snapshot时，将当前窗口的DoubleRecorder灌入DoubleHistogram。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/edf912ad688641ac911675821b052649~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=LDBndB4%2Be%2FJ0zP8nTH9%2FAxEAdqQ%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">由于</span>Prometheus只用<span style="color: black;">这儿</span>的分位数值，<span style="color: black;">因此</span>只用看valueAtPercentile，调用DoubleHistogram#getValueAtPercentile这个api<span style="color: black;">就可</span>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/54463ecadfda4a7e8adffe55cf8ac38d~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=stZzF3CwxZcHUeEp6OXSZcbLXgQ%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">因此</span><span style="color: black;">根据</span>这个<span style="color: black;">规律</span>，<span style="color: black;">是不是</span>能采集到分位数值其实和采集频率<span style="color: black;">相关</span>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">倘若</span>在一个时间窗口（1分钟）内不来采集，<span style="color: black;">那样</span>就不会调用累积Histogram<span style="color: black;">办法</span>，<span style="color: black;">那样</span>这个时间窗口的数据就会随着底层环形数组滚动而丢失。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">另外</span>，HdrHistogram统计Pxx总归是有误差的，不会把所有采样值都放到内存中。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/7786e03506ad481fb20bbcebd246f79f~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=4Ny0Lkc7moZvzc4snuUTX01Kq30%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">能够</span><span style="color: black;">经过</span><span style="color: black;">调节</span>DistributionStatisticConfig#<strong style="color: blue;">percentilePrecision</strong>来<span style="color: black;">提高</span>精度，<span style="color: black;">然则</span>耗费内存会更多。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">默认精度是1，<span style="color: black;">详细</span><span style="color: black;">规律</span>我<span style="color: black;">亦</span>不深究了。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/fed7af6ea9454b4fbdd032c6f12c7938~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=u0MiQ88SrV%2FY0fM%2FtXKHOuxksX0%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">TimeWindowFixedBoundaryHistogram</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在Prometheus场景下，TimeWindowFixedBoundaryHistogram仅用于<strong style="color: blue;">统计<span style="color: black;">每一个</span>桶中的采样数量</strong>。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">特点是PrometheusHistogram在构造父类时，写死了两个参数：</p><strong style="color: blue;">expiry</strong>：1825天，<span style="color: black;">寓意</span>着底层的环形数组永远不滚动；<strong style="color: blue;">bufferLength</strong>：1，<span style="color: black;">寓意</span>着底层的环形数组<span style="color: black;">仅有</span>一个元素；<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/60ea9eb27ca648bb9349b763c2380ae5~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=FVA7R8Kr0ccUcVNfadXZQiL2Zj4%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">从TimeWindowFixedBoundaryHistogram的泛型参数来看：</p>T：底层环形数组元素，是内部类TimeWindowFixedBoundaryHistogram.FixedBoundaryHistogram；U：Void，<span style="color: black;">因此</span>不支持累计Histogram；<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/2b7ca9768cd446e8a7eb073c2ca4e6e1~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=4scJKKhYFrF3H3YJS4guvqzhrdo%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">从成员变量来看，<span style="color: black;">重点</span>是有一组buckets。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">例如</span>案例会划分为57个bucket，<span style="color: black;">每一个</span>bucket的元素是一个时间值，从1毫秒到5秒。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/89866ce9211a4b009cb83445b799b85d~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=aPHorNwBp3NWJHbPxY%2Fa3WBiUTI%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">TimeWindowFixedBoundaryHistogram记录采样值：</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/0cfb6a2e5fb9435695751bb1fe9ce93e~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=JzvjwHQ7KoxZRBrb2%2BBTsd2Ckpk%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">TimeWindowFixedBoundaryHistogram获取桶内的采样数量，走cumulativeBucketCounts=true：</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/655f2befa0e1492f8474776aefa5ee6c~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=bVuna66pFrwsBxdDSmFkNZLeCEU%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">FixedBoundaryHistogram</strong><span style="color: black;">守护</span>了一个和bucket长度一致的原子长整型数组values。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/a9b45435d55c42508a1b5a1aaa07a0fd~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=dcooUomFdBtaV9cr8%2F3hvLDb8lY%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">FixedBoundaryHistogram#record<span style="color: black;">办法</span>：</p>从bucket数组中，找到最大的<span style="color: black;">少于</span>等于采样值的bucket下标（算法题二分<span style="color: black;">查询</span>变形）；values对应下标元素自增，即统计采样值到某个bucket中；<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/6139f5eda80e41f79a445a48f51d04b6~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=K60vG69bVE%2BUp%2B7Q5MTpUlc4ras%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">FixedBoundaryHistogram#countAtValueCumulative：</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">获取桶内数量的时候，Prometheus需要把该桶之前的数据累加。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">即0-1秒有1个请求，1-2秒有1个请求，入参2秒获取的数据<span style="color: black;">实质</span>是2个，和案例中一致。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/45b86593ed4146c0ab885b6788edda2f~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=J3VvGdysGtVNRndf7PK38K6bHhk%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">PrometheusHistogram</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">PrometheusHistogram<span style="color: black;">守护</span>了一组和父类<span style="color: black;">同样</span>的buckets数组，一组死值。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">特点在于PrometheusHistogram支持记录<span style="color: black;">每一个</span>bucket对应的Exemplar。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/2b5f6b663f7d441aa8606a3a9496f5fe~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=vO%2B5TW7w7qg7fRLmyF90BhKNAF4%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">每次采集数据，找到采样值所属bucket（二分），并记录Exemplar，<span style="color: black;">规律</span>和PrometheusCounter类似。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/4ff4c2c1c51640458ad0e74d63341ea8~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=PT04%2Bm7c9fxTKivxUIl4grrgZjo%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">关于业务埋点</h1>
<h1 style="color: black; text-align: left; margin-bottom: 10px;"><span style="color: black;">怎样</span>定义业务Meter</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">1、固定tag的Meter</strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">其实大部分Meter的tag都是可穷举可预知的。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">为了减少内存和cpu的浪费，不必在运行时去注册Meter到MeterRegistry，虽然MeterRegistry#getOrCreateMeter支持判断同一个Meter仅注册一次。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">例如</span>：Jvm内存分堆和非堆，<span style="color: black;">那样</span><span style="color: black;">运用</span>MeterBinder在ioc容器<span style="color: black;">起步</span><span style="color: black;">周期</span>就<span style="color: black;">能够</span>注册Meter了。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/f357bad34c5b48fb9e6882ee4ddd63ca~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=MciK5PCXi27Np4cL2bkGx52ATEI%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">例如</span>我要统计<span style="color: black;">区别</span>订单的下单数量的走势，<span style="color: black;">按照</span>订单类型枚举OrderType直接在ioc容器<span style="color: black;">起步</span><span style="color: black;">周期</span>注册Counter<span style="color: black;">就可</span>，运行时只需要调用increment api，而不需要再去走getOrCreateMeter。</p>typescript复制代码@Component
public class OrderMetrics implements MeterBinder {

private static final Map<OrderType, Counter> ORDER_COUNT = new HashMap<>();

@Override
public void bindTo(MeterRegistry meterRegistry) {
for (OrderType orderType : OrderType.values()) {
Counter counter = meterRegistry.counter("order.count", "order.type", orderType.getCode());
ORDER_COUNT.put(orderType, counter);
}
}

public void orderIncr(OrderType orderType) {
ORDER_COUNT.get(orderType).increment();
}
}<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">2、非固定tag的Meter</strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">有些<span style="color: black;">状况</span>，tag纬度<span style="color: black;">非常多</span>，且tag不太能穷举，只能在运行<span style="color: black;">周期</span>注册Meter到MeterRegistry</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">如DefaultMeterObservationHandler（springboot2不是这个），统计http请求耗时，默认tag纬度很多（uri+status+exception+method+outcome）不可能<span style="color: black;">起步</span><span style="color: black;">周期</span>穷举。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ca88b1d97bd14033a657ebb00f209c1c~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=98rVNrsUmF4sdYFPkfInMNb6FtI%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">举个不<span style="color: black;">必定</span>很恰当的例子，订单取消订单<span style="color: black;">原由</span>类型，<span style="color: black;">能够</span>无限扩充，仅用于放在看板上分析，不需要每次新增<span style="color: black;">原由</span>类型，就修改后端服务。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/88cec36b59fa4a598f695517994270ab~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=ynNwOhaVBjzYpqPEmzwI2Jk1LjQ%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">当然了，<span style="color: black;">运用</span>Prometheus采集metrics<span style="color: black;">咱们</span>应该避免<span style="color: black;">出现</span>高基数问题。</p>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">开箱即用的Meter</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">SpringBoot<span style="color: black;">供给</span>了<span style="color: black;">非常多</span>开箱即用的Meter，举几个<span style="color: black;">初期</span>版本不<span style="color: black;">必定</span>有的例子。</p>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">ThreadPoolTaskExecutor/ThreadPoolTaskScheduler</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">这两个类都是Spring<span style="color: black;">供给</span>的，包装了普通的jdk的线程池，<span style="color: black;">供给</span>了<span style="color: black;">非常多</span>在Spring里的<span style="color: black;">加强</span>功能。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">针对</span>这两类bean，SpringBoot会暴露线程池的<span style="color: black;">关联</span>meter，对业务<span style="color: black;">亦</span>比较有<span style="color: black;">帮忙</span>。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/bbd901d09815431b837b3c37c16372fb~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=xkyiIlaN5txU2O8kK2L8HUZoRa8%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">除了executor_completed是Counter之外，其他都是Guage。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ce161fd619c54c889199c391d469807c~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=aqBSW7OvW4SZvo1y61T%2Fgsietss%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">DefaultMeterObservationHandler</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在springboot<span style="color: black;">初期</span>版本，<span style="color: black;">运用</span>自己写的WebMvcMetricsFilter来记录http.server.requests指标。</p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">在新版本中，<span style="color: black;">运用</span>micrometer<span style="color: black;">供给</span>了DefaultMeterObservationHandler。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/3002ba29410b4802a391bcf534f9ecbb~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=iLvLoO1V3f3pjgcIMsN4DJ0jgcU%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">区别在于DefaultMeterObservationHandler不仅采集普通Timer的，还采集了LongTaskTimer，即<span style="color: black;">能够</span>看到正在处理（in-flight）的请求metrics。</p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/42cbeb40214b480a8937ea721d61dbbb~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728815862&x-signature=jdGoNlC2FW2WzrOq7gDZzwcCMYg%3D" style="width: 50%; margin-bottom: 20px;"></div>
<h1 style="color: black; text-align: left; margin-bottom: 10px;">总结</h1>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Mircometer的核心模型就两个：</p>Meter：<span style="color: black;">包括</span>一组瞬时Measurement度量，用一个<span style="color: black;">独一</span>标识Id（name+Tags）来标识这组度量；MeterRegistry：存储Meter的<span style="color: black;">地区</span>，getOrCreateMeter<span style="color: black;">办法</span><span style="color: black;">掌控</span>同一个Id的Meter只注册一个Meter实例；<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">注册Meter<span style="color: black;">通常</span>有两种方式：</p>实现MeterBinder接口，由ioc容器回调bindTo<span style="color: black;">办法</span>，注册Meter；运行时构造Meter实例，<span style="color: black;">经过</span>MeterRegistry#register API注册Meter；<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">五种Meter模型：</p>Counter：只<span style="color: black;">包括</span>一个只增不减的double类型度量，支持Exemplar；Gauge：只<span style="color: black;">包括</span>一个可增可减的double类型度量，不支持Exemplar；Timer：用于跟踪<span style="color: black;">海量</span><span style="color: black;">短期</span>运行事件的计时器，<span style="color: black;">包括</span>三个度量count总数、totalTime总耗时、max最长耗时。其中max默认统计的是3分钟内的最大值，基于环形数组实现，数组容量bufferLength=3，<span style="color: black;">每一个</span>元素<span style="color: black;">表率</span>时长expiry=1分钟。支持Histogram，依托Histogram支持Exemplar；LongTaskTimer：用于度量正在执行（in-flight）的任务，<span style="color: black;">包括</span>active_count正在执行任务数、duration正在执行任务总时长、max正在执行任务的最大时长，支持Histogram，依托Histogram支持Exemplar；DistributionSummary：和Timer的实现几乎一致，区别在于DistributionSummary用于统计非时间的任意值，支持Histogram，依托Histogram支持Exemplar；<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">关于Histogram：</p>桶计数：percentileHistogram=true开启桶计数，桶数量由minimumExpectedValue和maximumExpectedValue确定。在Prometheus场景下，桶计数需要累计<span style="color: black;">全部</span>进程生命周期中的所有计数，底层TimeWindowFixedBoundaryHistogram<span style="color: black;">守护</span>了一个永远不滚动的1容量的环形数组；分位数值：percentiles非空开启分位数值记录，分位数值数量由percentiles确定。收集时会将当前时间窗口内的计数，灌入累积Histogram，底层<span style="color: black;">运用</span>三方工具HdrHistogram实现；支持Exemplar：对于<span style="color: black;">每一个</span>桶，支持记录Exemplar；

nqkk58 发表于 2024-10-21 18:19:26

你的见解真是独到，让我受益良多。

m5k1umn 发表于 2024-10-24 18:19:15

对于这个问题，我有不同的看法...

b1gc8v 发表于 2024-10-26 20:33:33

期待你更多的精彩评论，一起交流学习。

4lqedz 发表于 2024-11-10 07:53:48

论坛的成功是建立在我们诚恳、务实、高效、创新和团结合作基础上，我们要把这种精神传递下去。

1fy07h 发表于 3 天前

谷歌外贸网站优化技术。

b1gc8v 发表于昨天 23:02

认真阅读了楼主的帖子，非常有益。

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Micrometer源码分析