Metrics-Scala

Capturing JVM- and application-level metrics. So you know what's going on.

This is the Scala API for Coda Hale's Metrics library.

Initially this project started out as a line for line copy of the Metrics-scala module, released for multiple scala versions. Metrics dropped the scala module in version 3.0.0 and this project continued separately with the help of @scullxbones.

Contents

• Usage
• Manual
• Manual (version 2.x)
• Features
• Available versions
• Download
• Support
• License

Usage

Metrics-scala provides an easy way to create metrics and health checks in Scala. Metrics-core requires an application wide MetricRegistry. Create an Instrumented trait that refers to that registry and extends the InstrumentedBuilder trait.

object YourApplication {
  /** The application wide metrics registry. */
  val metricRegistry = new com.codahale.metrics.MetricRegistry()
}
trait Instrumented extends nl.grons.metrics.scala.InstrumentedBuilder {
  val metricRegistry = YourApplication.metricRegistry
}

Now you can create metrics by using the metrics metrics builder.

class Example(db: Database) extends Instrumented {
  private[this] val loading = metrics.timer("loading")

  def loadStuff(): Seq[Row] = loading.time {
    db.fetchRows()
  }
}

For more detailed information see the manual. For more information on Metrics-core 3.x, please see the documentation.

See the change log for API changes compared to the 2.x versions.

Features

• Easy creation of all metrics types.
• Easy creation of Health Checks.
• Almost invisible syntax for using timers (see example above).
• Scala specific methods on metrics (e.g. += on counters).
• Derives proper metrics names for Scala objects and closures.
• Actor support (Scala 2.10 only).
• Future support (Scala 2.10 only).

Available versions

Please consult the table below to see which versions of metrics-scala are available for which scala versions.

Note that only the versions 2.1.4 and 2.1.5 support OSGI.

Metrics- scala version	Metrics- core version	Scala version
		2.9.1	2.9.1-1	2.9.2	2.9.3	2.10.x
2.1.2	same	✓	✓	✓
2.1.3	same	✓	✓	✓
2.1.4	same	✓	✓	✓
2.1.5	same	✓	✓	✓		✓
2.2.0	same	✓	✓	✓	✓	✓
3.0.0	same	✓	✓	✓	✓	✓
3.0.1	same	✓	✓	✓	✓	✓
3.0.2	3.0.1	✓	✓	✓	✓	✓
3.0.3 (Akka 2.2.0)	3.0.1	✓	✓	✓	✓	✓
3.0.3_a2.1.0 (Akka 2.1.0)	3.0.1					✓

If you need another version mix please open an issue, or sent an email to the metrics mailing list.

Download

SBT:

libraryDependencies += "nl.grons" %% "metrics-scala" % "3.0.3"

Maven:

<properties>
    <scala.version>2.10.0</scala.version>
    <scala.dep.version>2.10</scala.dep.version>
</properties>
<dependency>
    <groupId>nl.grons</groupId>
    <artifactId>metrics-scala_${scala.dep.version}</artifactId>
    <version>3.0.3</version>
</dependency>

Note: For scala versions before 2.10, you need to use the full scala version in the artifact name; e.g. metrics-scala_2.9.1-1.

Note: If you depend on JMX: 2.2.0 has a small bug that makes it inconvenient to use JMX.

Support

If you found a bug, please open an issue, better yet: send a pull request. For questions, please sent an email to the metrics mailing list.

License

Copyright (c) 2010-2012 Coda Hale, Yammer.com (before 3.0.0)

Copyright (c) 2013 Erik van Oosten (3.0.0 and later)

Published under Apache Software License 2.0, see LICENSE