Scala Logging

Scala Logging is a convenient and performant logging library wrapping logging libraries like SLF4J and potentially others.

It's convenient, because you can simply call log methods without checking whether the respective log level is enabled:

logger.debug(s"Some $expensive message!")

It's performant, because thanks to Scala macros the check-enabled-idiom is applied, just like writing this more involved code:

if (logger.isDebugEnabled) logger.debug(s"Some $expensive message!")

Prerequisites

Java 6 or higher
Scala 2.11 or Scala 2.10
Logging backend compatible with SLF4J, e.g. Logback

Getting Scala Logging

Scala Logging is published to Sonatype OSS and Maven Central:

Group id / organization: com.typesafe.scala-logging
Module (artifact id / name): scala-logging-slf4j for the SLF4J-backed implementation
Latest release version is 2.1.2

The following example shows how to add a dependency to the latest version of Scala Logging to your sbt build definition:

libraryDependencies += "com.typesafe.scala-logging" %% "scala-logging-slf4j" % "2.1.2"

Using Scala Logging

The com.typesafe.scalalogging.slf4j package contains the following members:

The Logger class wraps an underlying SLF4J logger and provides methods like error, info, etc. In order to create a Logger, you have to pass a SLF4J logger to the apply factory method defined in the Logger companion object:

val logger = Logger(LoggerFactory getLogger "name")

The Logging trait declares the logger member of type Logger, i.e. requires the class, into which this trait is mixed, to define a Logger.

The LazyLogging and StrictLogging traits implement the Logging. They define the logger member as a lazy or strict value respectively. In both cases the underlying SLF4J logger is named like the class into which these traits are mixed:

class MyClass extends LazyLogging {
  logger.debug("This is very convenient ;-)")
}

Contribution policy

Contributions via GitHub pull requests are gladly accepted from their original author. Before we can accept pull requests, you will need to agree to the Typesafe Contributor License Agreement online, using your GitHub account.

License