Add the LogLevel OFF that can be used to turn off logging. See #2965

Conflicts:
	akka-actor/src/main/scala/akka/actor/ActorRefProvider.scala
	akka-docs/rst/java/logging.rst
	akka-docs/rst/scala/logging.rst

akka-actor-tests/src/test/scala/akka/event/LoggerSpec.scala

@@ -0,0 +1,62 @@
+/**
+ * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.event
+
+import akka.testkit.AkkaSpec
+import com.typesafe.config.{ Config, ConfigFactory }
+import org.scalatest.WordSpec
+import akka.actor.ActorSystem
+import org.scalatest.matchers.MustMatchers
+
+object LoggerSpec {
+
+  val defaultConfig = ConfigFactory.parseString("""
+      akka {
+        stdout-loglevel = WARNING
+        loglevel = DEBUG
+      }
+    """).withFallback(AkkaSpec.testConf)
+
+  val noLoggingConfig = ConfigFactory.parseString("""
+      akka {
+        stdout-loglevel = OFF
+        loglevel = OFF
+      }
+    """).withFallback(AkkaSpec.testConf)
+}
+
+@org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
+class LoggerSpec extends WordSpec with MustMatchers {
+
+  import LoggerSpec._
+
+  private def createSystemAndLogToBuffer(name: String, config: Config) = {
+    val out = new java.io.ByteArrayOutputStream()
+    Console.withOut(out) {
+      val system = ActorSystem(name, config)
+      try {
+        system.log.error("Danger! Danger!")
+      } finally {
+        system.shutdown()
+      }
+    }
+    out
+  }
+
+  "A normally configured actor system" must {
+
+    "log messages to standard output" in {
+      val out = createSystemAndLogToBuffer("defaultLogger", defaultConfig)
+      out.size must be > (0)
+    }
+  }
+
+  "An actor system configured with the logging turned off" must {
+
+    "not log messages to standard output" in {
+      val out = createSystemAndLogToBuffer("noLogging", noLoggingConfig)
+      out.size must be(0)
+    }
+  }
+}

akka-actor/src/main/resources/reference.conf

@@ -29,11 +29,11 @@ akka {
 
   # Log level used by the configured loggers (see "loggers") as soon
   # as they have been started; before that, see "stdout-loglevel"
-  # Options: ERROR, WARNING, INFO, DEBUG
+  # Options: OFF, ERROR, WARNING, INFO, DEBUG
   loglevel = "INFO"
 
   # Log level for the very basic logger activated during AkkaApplication startup
-  # Options: ERROR, WARNING, INFO, DEBUG
+  # Options: OFF, ERROR, WARNING, INFO, DEBUG
   stdout-loglevel = "WARNING"
 
   # Log the complete configuration at INFO level when the actor system is started.

akka-actor/src/main/scala/akka/actor/ActorRefProvider.scala

@@ -455,7 +455,7 @@ class LocalActorRefProvider private[akka] (
 
     def stopWhenAllTerminationHooksDone(): Unit =
       if (terminationHooks.isEmpty) {
-        eventStream.stopDefaultLoggers()
+        eventStream.stopDefaultLoggers(system)
         context.stop(self)
       }
 

akka-actor/src/main/scala/akka/event/Logging.scala

@@ -67,19 +67,23 @@ trait LoggingBus extends ActorEventBus {
     _logLevel = level
   }
 
-  /**
+  private def setUpStdoutLogger(config: Settings) {
-   * Internal Akka use only
-   */
-  private[akka] def startStdoutLogger(config: Settings) {
     val level = levelFor(config.StdoutLogLevel) getOrElse {
       StandardOutLogger.print(Error(new LoggerException, simpleName(this), this.getClass, "unknown akka.stdout-loglevel " + config.StdoutLogLevel))
       ErrorLevel
     }
     AllLogLevels filter (level >= _) foreach (l ⇒ subscribe(StandardOutLogger, classFor(l)))
     guard.withGuard {
-      loggers = Seq(StandardOutLogger)
+      loggers :+= StandardOutLogger
       _logLevel = level
     }
+  }
+
+  /**
+   * Internal Akka use only
+   */
+  private[akka] def startStdoutLogger(config: Settings) {
+    setUpStdoutLogger(config)
     publish(Debug(simpleName(this), this.getClass, "StandardOutLogger started"))
   }
 
@@ -145,10 +149,10 @@ trait LoggingBus extends ActorEventBus {
   /**
    * Internal Akka use only
    */
-  private[akka] def stopDefaultLoggers() {
+  private[akka] def stopDefaultLoggers(system: ActorSystem) {
     val level = _logLevel // volatile access before reading loggers
     if (!(loggers contains StandardOutLogger)) {
-      AllLogLevels filter (level >= _) foreach (l ⇒ subscribe(StandardOutLogger, classFor(l)))
+      setUpStdoutLogger(system.settings)
       publish(Debug(simpleName(this), this.getClass, "shutting down: StandardOutLogger started"))
     }
     for {
@@ -424,17 +428,26 @@ object Logging {
   final val InfoLevel = LogLevel(3)
   final val DebugLevel = LogLevel(4)
 
+  /**
+   * Internal Akka use only
+   *
+   * Don't include the OffLevel in the AllLogLevels since we should never subscribe
+   * to some kind of OffEvent.
+   */
+  private final val OffLevel = LogLevel(Int.MinValue)
+
   /**
    * Returns the LogLevel associated with the given string,
    * valid inputs are upper or lowercase (not mixed) versions of:
    * "error", "warning", "info" and "debug"
    */
-  def levelFor(s: String): Option[LogLevel] = s match {
+  def levelFor(s: String): Option[LogLevel] = s.toLowerCase match {
-    case "ERROR" | "error"     ⇒ Some(ErrorLevel)
+    case "off"     ⇒ Some(OffLevel)
-    case "WARNING" | "warning" ⇒ Some(WarningLevel)
+    case "error"   ⇒ Some(ErrorLevel)
-    case "INFO" | "info"       ⇒ Some(InfoLevel)
+    case "warning" ⇒ Some(WarningLevel)
-    case "DEBUG" | "debug"     ⇒ Some(DebugLevel)
+    case "info"    ⇒ Some(InfoLevel)
-    case unknown               ⇒ None
+    case "debug"   ⇒ Some(DebugLevel)
+    case unknown   ⇒ None
   }
 
   /**

akka-docs/rst/general/configuration.rst

@@ -95,11 +95,11 @@ A custom ``application.conf`` might look like this::
 
     # Log level used by the configured loggers (see "loggers") as soon
     # as they have been started; before that, see "stdout-loglevel"
-    # Options: ERROR, WARNING, INFO, DEBUG
+    # Options: OFF, ERROR, WARNING, INFO, DEBUG
     loglevel = DEBUG
 
     # Log level for the very basic logger activated during AkkaApplication startup
-    # Options: ERROR, WARNING, INFO, DEBUG
+    # Options: OFF, ERROR, WARNING, INFO, DEBUG
     stdout-loglevel = DEBUG
 
     actor {

akka-docs/rst/java/logging.rst

@@ -56,7 +56,7 @@ You almost definitely need to have logging set to DEBUG to use any of the option
 .. code-block:: ruby
 
     akka {
-      loglevel = DEBUG
+      loglevel = "DEBUG"
     }
 
 This config option is very good if you want to know what config settings are loaded by Akka:
@@ -153,6 +153,20 @@ If you want to see all messages that are received through remoting at DEBUG log
 
 Also see the logging options for TestKit: :ref:`actor.logging-java`.
 
+Turn Off Logging
+----------------
+
+To turn off logging you can configure the log levels to be ``OFF`` like this.
+
+.. code-block:: ruby
+
+  akka {
+    stdout-loglevel = "OFF"
+    loglevel = "OFF"
+  }
+
+The ``stdout-loglevel`` is only in effect during system startup and shutdown, and setting
+it to ``OFF`` as well, ensures that nothing gets logged during system startup or shutdown.
 
 Loggers
 =======
@@ -167,7 +181,7 @@ Here you can also define the log level.
     # Loggers to register at boot time (akka.event.Logging$DefaultLogger logs
     # to STDOUT)
     loggers = ["akka.event.Logging$DefaultLogger"]
-    # Options: ERROR, WARNING, INFO, DEBUG
+    # Options: OFF, ERROR, WARNING, INFO, DEBUG
     loglevel = "DEBUG"
   }
 

akka-docs/rst/scala/logging.rst

@@ -57,7 +57,7 @@ You almost definitely need to have logging set to DEBUG to use any of the option
 .. code-block:: ruby
 
     akka {
-      loglevel = DEBUG
+      loglevel = "DEBUG"
     }
 
 This config option is very good if you want to know what config settings are loaded by Akka:
@@ -196,6 +196,21 @@ purposes as it contains exactly the default behavior.
   to look up the logger instance to use instead of the class’ name), and you
   might want to do this also in case you implement your own logging adapter.
 
+Turn Off Logging
+----------------
+
+To turn off logging you can configure the log levels to be ``OFF`` like this.
+
+.. code-block:: ruby
+
+  akka {
+    stdout-loglevel = "OFF"
+    loglevel = "OFF"
+  }
+
+The ``stdout-loglevel`` is only in effect during system startup and shutdown, and setting
+it to ``OFF`` as well, ensures that nothing gets logged during system startup or shutdown.
+
 Loggers
 =======
 
@@ -210,7 +225,7 @@ also define the log level.
     # Loggers to register at boot time (akka.event.Logging$DefaultLogger logs
     # to STDOUT)
     loggers = ["akka.event.Logging$DefaultLogger"]
-    # Options: ERROR, WARNING, INFO, DEBUG
+    # Options: OFF, ERROR, WARNING, INFO, DEBUG
     loglevel = "DEBUG"
   }