SLF4J log level is only error in 1.0.0-RC3

steps

Execute a task that calls a slf4j logger (e.g. from a dependency or directly from the task)

  def testLoggingTask: Def.Initialize[Task[Unit]] = Def.task {
    val log: Logger = streams.value.log

    log.info("sbt streams")

    val logger = LoggerFactory.getLogger("SLF4J logger")
    logger.info("slf4j logger")
    logger.warn("slf4j logger")
    logger.error("slf4j logger")
  }

problem

With sbt 1.0.0-RC3 logging output is different than in sbt 0.13.16. Only errors is logged.

[info] Set current project to root (in build file:/C:/Users/-/AppData/Local/Temp/sbt_c768fa02/testLogging/)
[info] sbt streams
[pool-5-thread-1] ERROR SLF4J logger - slf4j logger

expectation

Logging output is reported for all log levels that are configured, e.g. logLevel := Level.Debug where info is the default if not configured.

[info] Set current project to root (in build file:/C:/Users/-/AppData/Local/Temp/sbt_b9e14e18/testLogging/)
[info] sbt streams
[pool-4-thread-1] INFO SLF4J logger - slf4j logger
[pool-4-thread-1] WARN SLF4J logger - slf4j logger
[pool-4-thread-1] ERROR SLF4J logger - slf4j logger

notes

The possibility to set the log-level for specific packages/classes used in plugins via a system property is not working with 1.0.0-RC3 neither. Should mention that I have slf4j-simple and slf4-api in the classpath when running with sbt 0.13.16.

initialize ~= { _ =>
	sys.props += (("org.slf4j.simpleLogger.log.my.package", "info"))
}

sbt version: 1.0.0-RC3

[albuch]

@eed3si9n could you point in any direction where to start looking? This is getting more and more annoying without even having a workaround.

[anilkumarmyla]

I could get the testLoggingTask working by passing -Dlog4j2.level=debug to sbt.

Ref https://logging.apache.org/log4j/2.0/manual/configuration.html#SystemProperties

The crux of the problem appears to be log4j2 not setting root logging level to the level defined in sbt (logLevel) . You can pass -Dlog4j2.debug to sbt and you can see this in motion

WARN StatusLogger No Root logger was configured, creating default ERROR-level Root logger with Console appender