Metrics Aspect

This project provides a way of generating Dropwizard metrics based on Spring AOP. The below usage shows on how to use different types of metric annotations. Th example module shows you how to use the metric-aspect library with Spring Boot.

Usage

Timed Annotation

@Timed annotation is used to generate timer metrics. A timer aggregates timing durations and provides duration and throughput statistics. A @Timed annotation can be used at class or method level.

package com.example;

@Timed
private class MyClass {
    public String myMethod(String name) {
        return "Hello " + name;
    }
    
}

package com.example;

private class MyClass {
    @Timed
    public String myMethod(String name) {
        return "Hello " + name;
   }
}

It will generate metrics having the following name when method myMethod is executed:

timer.com.example.MyClass.myMethod

You can customize the name of your metric in couple of different ways by providing values for name and absolute parameters of @Timed annotation. It allows you to aggregate metrics from different methods of a class or classes.

package com.example;

private class MyClass {
    @Timed(name="myMetric")
    public String myMethod(String name) {
        return "Hello " + name;
   }
}

It will generate metrics having the following name when method myMethod is executed:

timer.com.example.MyClass.myMetric

You can also make the absolute attribute to be true (default is false).

package com.example;

private class MyClass {
    @Timed(name="myMetric", absolute=true)
    public String myMethod(String name) {
        return "Hello " + name;
   }
}

It will generate metrics having the following name when method myMethod is executed:

timer.myMetric

Metered Annotation

@Metered annotation is used to generate meter metrics. A meter provides throughput statistics. Like @Timed annotation, a @Metered annotation can be used at class or method level. Similarly you can use name and absolute parameters of @Metered annotation to customize metric names.

@Metered annotation will generate metrics having the following name when method myMethod is executed:

meter.com.example.MyClass.myMetric

Similary, the customize metrics will have the following format:

meter.com.example.MyClass.myMetric
meter.myMetric

Exception Metered Annotation

@ExceptionMetered annotation is used to generate meter metrics when exception occurs. A @ExceptionMetered annotation can be used at class or method level. Similarly you can use name and absolute parameters of @Metered annotation to customize metric names. You can also specify the exception type to report a specific exception.

package com.example;

private class MyClass {
    @ExceptionMetered(cause =IllegalArgumentException.class)
    public String myMethod(String name) {
        return "Hello " + name;
   }
}

@ExceptionMetered annotation will generate metrics having the following name when method myMethod is executed:

exception.com.example.MyClass.myMetric

Similary, the customize metrics will have the following format:

exception.com.example.MyClass.myMetric
exception.myMetric

Custom JMX Metrics

There are cases where Dropwizard do not provide metrics you're interested. Some of this metrics are published as JMX MBeans such as Jetty or Tomcat thread pools. This project includes a custom JMXGaugeSet class which provides the ability to publish a JMX MBean as Dropwizard metrics.

Here's an example of publishing the Tomcat threadpool JMX MBean having ObjectName of Tomcat:type=ThreadPool,name="http-nio-8080", as Dropwizard metrics:

@Configuration
public class MyConfiguration {

    @Autowired
    private MetricRegistry registry;

    @PostConstruct
    public void init() {
        registry.register(
                MetricRegistry.name("tomcat", "threadpool", "http-nio-8080"),
                new JmxGaugeSet("Tomcat:type=ThreadPool,name=\"http-nio-8080\""));
    }
}

Metric Fiter

There may be cases when you want to filter metrics based on name. In order to filter metrics add a YAML configuration file either in classpath or file system and specify the name of the file in property metrics.filter.

metrics:
  filter: metric-filter.yml

Metrics you would like to show up as JMX MBeans are specified in a YAML file, named metric-filter.yml (same names as specified in the metrics.filter property.

filter:
  properties:
    "[jvm.memory.pools]":
      type: memory
    "[jvm.memory.heap]":
      type: memory
    "[timer.org.basaki.example.book.controller.BookController.read]":
      type: gauge