Play's logging API

Play exposes the logging API through play.api.Logger. Let's have a look at the class and object definition of it:

class Logger(val logger: Slf4jLogger) extends LoggerLike

object Logger extends LoggerLike {

  ...
  val logger = LoggerFactory.getLogger("application")

  def apply(name: String): Logger = new Logger(LoggerFactory.getLogger(name))

  def apply[T](clazz: Class[T]): Logger = new Logger(LoggerFactory.getLogger(clazz))

  ...

}

The LoggerLike trait is just a wrapper over Slf4jLogger. By default, all application logs are mapped to Logger with the application name and the Play-related logs are mapped to Logger with the Play name.

After importing play.api.Logger, we can use the default logger or define a custom one in these ways:

• By using a default logger:

  import play.api.Logger
  object Task{
    def delete(id:Long) = {
      logger.debug(s"deleting task with id $id")
      ...
    }
  }

• By using a logger with its class name:

  import play.api.Logger
  object Task{
    private lazy val...