metrics的简单介绍
metrics是一种性能指标工具，有很多开源工具使用之来来作为其性能监控，如Hadoop，Kafka，Spark，JStorm等。
metrics使用最主要有三个东西:
- Metric Registries
- Metrics 度量指标的类型
- Metrics Report 数据展示方案
metricsRegistry
MetricRegistry类是Metrics的核心，它是存放应用中所有metrics的容器。也是我们使用 Metrics 库的起点。
每一个 metric 都有它独一无二的名字，Metrics 中使用句点名字，如 com.example.Queue.size。当你在 com.example.Queue 下有两个 metric 实例，可以指定地更具体：com.example.Queue.requests.size 和 com.example.Queue.response.size 。使用MetricRegistry类，可以非常方便地生成名字。
五种Metrics类型
guages
最简单的度量指标，只有一个简单的返回值，或者叫瞬时状态，例如，我们想衡量一个待处理队列中任务的个数。
Counters
Counter 就是计数器，Counter 只是用 Gauge 封装了 AtomicLong 。
Meters
Meter度量一系列事件发生的速率(rate)，例如TPS。Meters会统计最近1分钟，5分钟，15分钟，还有全部时间的速率。
Histograms
Histogram统计数据的分布情况。比如最小值，最大值，中间值，还有中位数，75百分位, 90百分位, 95百分位, 98百分位, 99百分位, 和 99.9百分位的值(percentiles)。
Timers
Timer其实是 Histogram 和 Meter 的结合， histogram 某部分代码/调用的耗时， meter统计TPS。
怎么使用暂时不给出代码了，先来看看如何统计接口的tps
Metrics Report
metrics提供了丰富的Report，如JMX、Console、CSV、SLF4J以及图形、HTTP等等
统计接口tps
我采取的办法是使用spring的interceptor与Meters ，Report使用的是ConsoleReport，代码如下
package lew.bing.exp.spr;
import com.codahale.metrics.ConsoleReporter;
import com.codahale.metrics.Meter;
import com.codahale.metrics.Metric;
import com.codahale.metrics.MetricRegistry;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
/**
* Created by 刘国兵 on 2018/7/14.
*/
public class MetricsInterceptor implements HandlerInterceptor {
private Map<String,Meter> metricMap = new HashMap<>();
private MetricRegistry metrics = new MetricRegistry();
public MetricsInterceptor() {
metricMap.put("/",metrics.meter("/"));
ConsoleReporter reporter = ConsoleReporter.forRegistry(metrics)
.convertRatesTo(TimeUnit.SECONDS)
.convertDurationsTo(TimeUnit.MILLISECONDS)
.build();
reporter.start(1, TimeUnit.SECONDS);// 1s报道一次
}
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
String servletPath = request.getServletPath();
if (metricMap.containsKey(servletPath)) {
metricMap.get(servletPath).mark();// 统计tps
}
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
// 可以统计失败以及成功次数
}
}
连续点击浏览器请求接口，控制台打印如下:
18-7-14 18:36:08 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 3
mean rate = 0.60 events/second
1-minute rate = 0.60 events/second
5-minute rate = 0.60 events/second
15-minute rate = 0.60 events/second
18-7-14 18:36:09 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 10
mean rate = 1.67 events/second
1-minute rate = 0.60 events/second
5-minute rate = 0.60 events/second
15-minute rate = 0.60 events/second
18-7-14 18:36:10 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 15
mean rate = 2.14 events/second
1-minute rate = 0.60 events/second
5-minute rate = 0.60 events/second
15-minute rate = 0.60 events/second
18-7-14 18:36:11 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 21
mean rate = 2.62 events/second
1-minute rate = 0.60 events/second
5-minute rate = 0.60 events/second
15-minute rate = 0.60 events/second
18-7-14 18:36:12 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 27
mean rate = 3.00 events/second
1-minute rate = 0.60 events/second
5-minute rate = 0.60 events/second
15-minute rate = 0.60 events/second
18-7-14 18:36:13 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 33
mean rate = 3.30 events/second
1-minute rate = 1.03 events/second
5-minute rate = 0.69 events/second
15-minute rate = 0.63 events/second
18-7-14 18:36:14 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 38
mean rate = 3.45 events/second
1-minute rate = 1.03 events/second
5-minute rate = 0.69 events/second
15-minute rate = 0.63 events/second
18-7-14 18:36:15 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 44
mean rate = 3.66 events/second
1-minute rate = 1.03 events/second
5-minute rate = 0.69 events/second
15-minute rate = 0.63 events/second
18-7-14 18:36:16 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 50
mean rate = 3.84 events/second
1-minute rate = 1.03 events/second
5-minute rate = 0.69 events/second
15-minute rate = 0.63 events/second
18-7-14 18:36:17 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 55
mean rate = 3.93 events/second
1-minute rate = 1.03 events/second
5-minute rate = 0.69 events/second
15-minute rate = 0.63 events/second
18-7-14 18:36:18 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 61
mean rate = 4.06 events/second
1-minute rate = 1.40 events/second
5-minute rate = 0.77 events/second
15-minute rate = 0.66 events/second
18-7-14 18:36:19 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 67
mean rate = 4.19 events/second
1-minute rate = 1.40 events/second
5-minute rate = 0.77 events/second
15-minute rate = 0.66 events/second
18-7-14 18:36:20 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 72
mean rate = 4.23 events/second
1-minute rate = 1.40 events/second
5-minute rate = 0.77 events/second
15-minute rate = 0.66 events/second
18-7-14 18:36:21 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 78
mean rate = 4.33 events/second
1-minute rate = 1.40 events/second
5-minute rate = 0.77 events/second
15-minute rate = 0.66 events/second
18-7-14 18:36:22 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 83
mean rate = 4.37 events/second
1-minute rate = 1.40 events/second
5-minute rate = 0.77 events/second
15-minute rate = 0.66 events/second
18-7-14 18:36:23 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 89
mean rate = 4.45 events/second
1-minute rate = 1.73 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:24 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 4.38 events/second
1-minute rate = 1.73 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:25 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 4.18 events/second
1-minute rate = 1.73 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:26 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 4.00 events/second
1-minute rate = 1.73 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:27 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 3.83 events/second
1-minute rate = 1.73 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:28 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 3.68 events/second
1-minute rate = 1.64 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:29 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 3.54 events/second
1-minute rate = 1.64 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:30 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 3.41 events/second
1-minute rate = 1.64 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:31 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 3.29 events/second
1-minute rate = 1.64 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:32 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 3.17 events/second
1-minute rate = 1.64 events/second
5-minute rate = 0.85 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:33 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 3.07 events/second
1-minute rate = 1.51 events/second
5-minute rate = 0.83 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:34 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 2.97 events/second
1-minute rate = 1.51 events/second
5-minute rate = 0.83 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:35 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 2.87 events/second
1-minute rate = 1.51 events/second
5-minute rate = 0.83 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:36 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 2.79 events/second
1-minute rate = 1.51 events/second
5-minute rate = 0.83 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:37 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 2.71 events/second
1-minute rate = 1.51 events/second
5-minute rate = 0.83 events/second
15-minute rate = 0.68 events/second
18-7-14 18:36:38 ===============================================================
-- Meters ----------------------------------------------------------------------
/
count = 92
mean rate = 2.63 events/second
1-minute rate = 1.39 events/second
5-minute rate = 0.82 events/second
15-minute rate = 0.68 events/second
简单的使用metrics统计tps就介绍到这，metrics还有健康检查，可以用来检测连接数据库是否可用等，感兴趣的同学可以多了解了解。
作者：247609107a39
链接：https://www.jianshu.com/p/f9b911a651ff
来源：简书
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