This module provides some support for @codahale Metrics library in a Play2 application (Scala)

Play Version: 2.7.0, Metrics Version: 4.0.5, Scala Versions: 2.12.8

1. Default Metrics Registry
2. Metrics Servlet
3. Filter to instrument http requests

Add metrics-play dependency:

    val appDependencies = Seq(
    ...
    "com.kenshoo" %% "metrics-play" % "2.7.3_0.8.2"
    )

To enable the module:

add to application.conf the following line

 play.modules.enabled+="com.kenshoo.play.metrics.PlayModule"

To add a custom metrics, you can use defaultRegistry which returns an instance of MetricRegistry.

     import com.kenshoo.play.metrics.Metrics
     import com.codahale.metrics.Counter

     class SomeController @Inject() (metrics: Metrics) {
         val counter = metrics.defaultRegistry.counter("name")
         counter.inc()
     }

An implementation of the metrics-servlet as a play2 controller.

It exports all registered metrics as a json document.

To enable the controller add a mapping to conf/routes file

 GET     /admin/metrics              com.kenshoo.play.metrics.MetricsController.metrics

Some configuration is supported through the default configuration file:

metrics.rateUnit - (default is SECONDS)

metrics.durationUnit (default is SECONDS)

metrics.showSamples [true/false] (default is false)

metrics.jvm - [true/false] (default is true) controls reporting jvm metrics

metrics.logback - [true/false] (default is true) controls reporing logback metrics

An implementation of the Metrics' instrumenting filter for Play2. It records requests duration, number of active requests and counts each return code

    import com.kenshoo.play.metrics.MetricsFilter
    import play.api.mvc._

    class Filters @Inject() (metricsFilter: MetricsFilter) extends HttpFilters {
        val filters = Seq(metricsFilter)
    }

By default, metrics are prefixed with "com.kenshoo.play.metrics.MetricsFilter".

"com.kenshoo.play.metrics.MetricsFilter.200" : {
   "count" : 1584456,
   "m15_rate" : 1.6800220918042639,
   "m1_rate" : 1.9015104460758263,
   "m5_rate" : 1.8138545372237085,
   "mean_rate" : 3.20162010446889,
   "units" : "events/second"
},

You can change the prefix by extending MetricsFilterImpl.

package myapp

import javax.inject.Inject

import com.kenshoo.play.metrics.{MetricsImpl, MetricsFilter, Metrics, MetricsFilterImpl}
import play.api.http.Status
import play.api.inject.Module
import play.api.{Configuration, Environment}

class MyMetricsFilter @Inject() (metrics: Metrics) extends MetricsFilterImpl(metrics) {

  // configure metrics prefix
  override def labelPrefix: String = "foobar"

  // configure status codes to be monitored. other status codes are labeled as "other"
  override def knownStatuses = Seq(Status.OK)
}

class MyMetricsModule extends Module {
  def bindings(environment: Environment, configuration: Configuration) = {
    Seq(
      bind[MetricsFilter].to[MyMetricsFilter].eagerly,
      bind[Metrics].to[MetricsImpl].eagerly
    )
  }
}

and add the following line to application.conf

play.modules.enabled+="myapp.MyMetricsModule"

• 2.7.3_0.8.2 - Minor compatability fix for Play 2.8
• 2.7.3_0.8.1 - Upgrade to play 2.7.3 and support Scala version 2.12.8 / 2.13.0 with dropwizard 4.0.5
• 2.7.0_0.8.0 - Upgrade to play 2.7.0 and Scala 2.12.8 and dropwizard 4.0.5
• 2.6.19_0.7.0 - Upgrade to play 2.6.19 and Scala 2.12.6 and dropwizard 4.0.3
• 2.6.2_0.6.1 - Upgrade to play 2.6 and Scala 2.12. Migration: If you get errors like "No configuration setting found ..." when building fat JARs, check your merge strategy for reference.conf.
• 2.4.0_0.4.0 - Re-implement as Play Module
• 2.4.0_0.3.0 - Upgrade to play 2.4, metrics 3.1.2
• 2.3.0_0.2.1 - Breaking Change! prefix jvm metric names to standardize with dropwizard
• 2.3.0_0.2.0 - Meter uncaught exceptions as 500 Internal Server Error
• 2.3.0_0.1.9 - Add extra http codes, support configurable metrics names for requests filter
• 2.3.0_0.1.8 - Support default registry in play java. Replace MetricsRegistry.default with MetricsRegistry.defaultRegistry (to support java where default is a reserved keyword)

This code is released under the Apache Public License 2.0.