Merge pull request #68 from eed3si9n/topic/logging

Reimplement multi-logger using log4j2

build.sbt

@@ -2,7 +2,7 @@ import Dependencies._
 import Util._
 import com.typesafe.tools.mima.core._, ProblemFilters._
 
-def baseVersion: String = "0.1.0-M16"
+def baseVersion: String = "1.0.0-M18"
 def internalPath   = file("internal")
 
 def commonSettings: Seq[Setting[_]] = Seq(
@@ -98,12 +98,14 @@ lazy val utilComplete = (project in internalPath / "util-complete").
 
 // logging
 lazy val utilLogging = (project in internalPath / "util-logging").
+  enablePlugins(ContrabandPlugin, JsonCodecPlugin).
   dependsOn(utilInterface, utilTesting % Test).
   settings(
     commonSettings,
     crossScalaVersions := Seq(scala210, scala211, scala212),
     name := "Util Logging",
-    libraryDependencies += jline
+    libraryDependencies ++= Seq(jline, log4jApi, log4jCore, disruptor, sjsonnewScalaJson),
+    sourceManaged in (Compile, generateContrabands) := baseDirectory.value / "src" / "main" / "contraband-scala"
   )
 
 // Relation
@@ -150,7 +152,8 @@ lazy val utilTesting = (project in internalPath / "util-testing").
     crossScalaVersions := Seq(scala210, scala211, scala212),
     name := "Util Testing",
     libraryDependencies ++= Seq(scalaCheck, scalatest)
-  )
+  ).
+  configure(addSbtIO)
 
 lazy val utilScripted = (project in internalPath / "util-scripted").
   dependsOn(utilLogging).

internal/util-logging/src/main/contraband-scala/sbt/internal/util/AbstractEntry.scala

@@ -0,0 +1,27 @@
+/**
+ * This code is generated using sbt-datatype.
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.util
+abstract class AbstractEntry(
+  val channelName: Option[String],
+  val execId: Option[String]) extends Serializable {
+  
+  
+  
+  
+  override def equals(o: Any): Boolean = o match {
+    case x: AbstractEntry => (this.channelName == x.channelName) && (this.execId == x.execId)
+    case _ => false
+  }
+  override def hashCode: Int = {
+    37 * (37 * (17 + channelName.##) + execId.##)
+  }
+  override def toString: String = {
+    "AbstractEntry(" + channelName + ", " + execId + ")"
+  }
+}
+object AbstractEntry {
+  
+}

internal/util-logging/src/main/contraband-scala/sbt/internal/util/ChannelLogEntry.scala

@@ -0,0 +1,51 @@
+/**
+ * This code is generated using sbt-datatype.
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.util
+final class ChannelLogEntry private (
+  val level: String,
+  val message: String,
+  channelName: Option[String],
+  execId: Option[String]) extends sbt.internal.util.AbstractEntry(channelName, execId) with Serializable {
+  
+  
+  
+  override def equals(o: Any): Boolean = o match {
+    case x: ChannelLogEntry => (this.level == x.level) && (this.message == x.message) && (this.channelName == x.channelName) && (this.execId == x.execId)
+    case _ => false
+  }
+  override def hashCode: Int = {
+    37 * (37 * (37 * (37 * (17 + level.##) + message.##) + channelName.##) + execId.##)
+  }
+  override def toString: String = {
+    "ChannelLogEntry(" + level + ", " + message + ", " + channelName + ", " + execId + ")"
+  }
+  protected[this] def copy(level: String = level, message: String = message, channelName: Option[String] = channelName, execId: Option[String] = execId): ChannelLogEntry = {
+    new ChannelLogEntry(level, message, channelName, execId)
+  }
+  def withLevel(level: String): ChannelLogEntry = {
+    copy(level = level)
+  }
+  def withMessage(message: String): ChannelLogEntry = {
+    copy(message = message)
+  }
+  def withChannelName(channelName: Option[String]): ChannelLogEntry = {
+    copy(channelName = channelName)
+  }
+  def withChannelName(channelName: String): ChannelLogEntry = {
+    copy(channelName = Option(channelName))
+  }
+  def withExecId(execId: Option[String]): ChannelLogEntry = {
+    copy(execId = execId)
+  }
+  def withExecId(execId: String): ChannelLogEntry = {
+    copy(execId = Option(execId))
+  }
+}
+object ChannelLogEntry {
+  
+  def apply(level: String, message: String, channelName: Option[String], execId: Option[String]): ChannelLogEntry = new ChannelLogEntry(level, message, channelName, execId)
+  def apply(level: String, message: String, channelName: String, execId: String): ChannelLogEntry = new ChannelLogEntry(level, message, Option(channelName), Option(execId))
+}

internal/util-logging/src/main/contraband-scala/sbt/internal/util/codec/AbstractEntryFormats.scala

@@ -0,0 +1,10 @@
+/**
+ * This code is generated using sbt-datatype.
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.util.codec
+import _root_.sjsonnew.{ deserializationError, serializationError, Builder, JsonFormat, Unbuilder }
+trait AbstractEntryFormats { self: sjsonnew.BasicJsonProtocol with sbt.internal.util.codec.ChannelLogEntryFormats =>
+implicit lazy val AbstractEntryFormat: JsonFormat[sbt.internal.util.AbstractEntry] = flatUnionFormat1[sbt.internal.util.AbstractEntry, sbt.internal.util.ChannelLogEntry]("type")
+}

internal/util-logging/src/main/contraband-scala/sbt/internal/util/codec/ChannelLogEntryFormats.scala

@@ -0,0 +1,33 @@
+/**
+ * This code is generated using sbt-datatype.
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.util.codec
+import _root_.sjsonnew.{ deserializationError, serializationError, Builder, JsonFormat, Unbuilder }
+trait ChannelLogEntryFormats { self: sjsonnew.BasicJsonProtocol =>
+implicit lazy val ChannelLogEntryFormat: JsonFormat[sbt.internal.util.ChannelLogEntry] = new JsonFormat[sbt.internal.util.ChannelLogEntry] {
+  override def read[J](jsOpt: Option[J], unbuilder: Unbuilder[J]): sbt.internal.util.ChannelLogEntry = {
+    jsOpt match {
+      case Some(js) =>
+      unbuilder.beginObject(js)
+      val level = unbuilder.readField[String]("level")
+      val message = unbuilder.readField[String]("message")
+      val channelName = unbuilder.readField[Option[String]]("channelName")
+      val execId = unbuilder.readField[Option[String]]("execId")
+      unbuilder.endObject()
+      sbt.internal.util.ChannelLogEntry(level, message, channelName, execId)
+      case None =>
+      deserializationError("Expected JsObject but found None")
+    }
+  }
+  override def write[J](obj: sbt.internal.util.ChannelLogEntry, builder: Builder[J]): Unit = {
+    builder.beginObject()
+    builder.addField("level", obj.level)
+    builder.addField("message", obj.message)
+    builder.addField("channelName", obj.channelName)
+    builder.addField("execId", obj.execId)
+    builder.endObject()
+  }
+}
+}

internal/util-logging/src/main/contraband-scala/sbt/internal/util/codec/JsonProtocol.scala

@@ -0,0 +1,10 @@
+/**
+ * This code is generated using sbt-datatype.
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.util.codec
+trait JsonProtocol extends sjsonnew.BasicJsonProtocol
+  with sbt.internal.util.codec.ChannelLogEntryFormats
+  with sbt.internal.util.codec.AbstractEntryFormats
+object JsonProtocol extends JsonProtocol

internal/util-logging/src/main/contraband/logging.contra

@@ -0,0 +1,16 @@
+package sbt.internal.util
+@target(Scala)
+@codecPackage("sbt.internal.util.codec")
+@fullCodec("JsonProtocol")
+
+interface AbstractEntry {
+  channelName: String
+  execId: String
+}
+
+type ChannelLogEntry implements sbt.internal.util.AbstractEntry {
+  level: String!
+  message: String!
+  channelName: String
+  execId: String
+}

internal/util-logging/src/main/scala/sbt/internal/util/ConsoleAppender.scala

@@ -1,13 +1,69 @@
-/* sbt -- Simple Build Tool
- * Copyright 2008, 2009, 2010, 2011 Mark Harrah
- */
 package sbt.internal.util
 
 import sbt.util._
 import java.io.{ PrintStream, PrintWriter }
 import java.util.Locale
+import java.util.concurrent.atomic.AtomicInteger
+import org.apache.logging.log4j.{ Level => XLevel }
+import org.apache.logging.log4j.message.{ Message, ParameterizedMessage, ObjectMessage }
+import org.apache.logging.log4j.core.{ LogEvent => XLogEvent }
+import org.apache.logging.log4j.core.appender.AbstractAppender
+import org.apache.logging.log4j.core.layout.PatternLayout
+import org.apache.logging.log4j.core.async.RingBufferLogEvent
+
+import ConsoleAppender._
 
 object ConsoleLogger {
+  // These are provided so other modules do not break immediately.
+  @deprecated("Use ConsoleAppender.", "0.13.x")
+  final val ESC = ConsoleAppender.ESC
+  @deprecated("Use ConsoleAppender.", "0.13.x")
+  private[sbt] def isEscapeTerminator(c: Char): Boolean = ConsoleAppender.isEscapeTerminator(c)
+  @deprecated("Use ConsoleAppender.", "0.13.x")
+  def hasEscapeSequence(s: String): Boolean = ConsoleAppender.hasEscapeSequence(s)
+  @deprecated("Use ConsoleAppender.", "0.13.x")
+  def removeEscapeSequences(s: String): String = ConsoleAppender.removeEscapeSequences(s)
+  @deprecated("Use ConsoleAppender.", "0.13.x")
+  val formatEnabled = ConsoleAppender.formatEnabled
+  @deprecated("Use ConsoleAppender.", "0.13.x")
+  val noSuppressedMessage = ConsoleAppender.noSuppressedMessage
+
+  def apply(out: PrintStream): ConsoleLogger = apply(ConsoleOut.printStreamOut(out))
+  def apply(out: PrintWriter): ConsoleLogger = apply(ConsoleOut.printWriterOut(out))
+  def apply(out: ConsoleOut = ConsoleOut.systemOut, ansiCodesSupported: Boolean = ConsoleAppender.formatEnabled,
+    useColor: Boolean = ConsoleAppender.formatEnabled, suppressedMessage: SuppressedTraceContext => Option[String] = ConsoleAppender.noSuppressedMessage): ConsoleLogger =
+    new ConsoleLogger(out, ansiCodesSupported, useColor, suppressedMessage)
+}
+
+/**
+ * A logger that logs to the console.  On supported systems, the level labels are
+ * colored.
+ */
+class ConsoleLogger private[ConsoleLogger] (val out: ConsoleOut, override val ansiCodesSupported: Boolean, val useColor: Boolean, val suppressedMessage: SuppressedTraceContext => Option[String]) extends BasicLogger {
+  private[sbt] val appender = ConsoleAppender(generateName, out, ansiCodesSupported, useColor, suppressedMessage)
+
+  override def control(event: ControlEvent.Value, message: => String): Unit =
+    appender.control(event, message)
+  override def log(level: Level.Value, message: => String): Unit =
+    {
+      if (atLevel(level)) {
+        appender.appendLog(level, message)
+      }
+    }
+
+  override def success(message: => String): Unit =
+    {
+      if (successEnabled) {
+        appender.success(message)
+      }
+    }
+  override def trace(t: => Throwable): Unit =
+    appender.trace(t, getTrace)
+
+  override def logAll(events: Seq[LogEvent]) = out.lockObject.synchronized { events.foreach(log) }
+}
+
+object ConsoleAppender {
   /** Escape character, used to introduce an escape sequence. */
   final val ESC = '\u001B'
 
@@ -122,25 +178,83 @@ object ConsoleLogger {
   private[this] def os = System.getProperty("os.name")
   private[this] def isWindows = os.toLowerCase(Locale.ENGLISH).indexOf("windows") >= 0
 
-  def apply(out: PrintStream): ConsoleLogger = apply(ConsoleOut.printStreamOut(out))
-  def apply(out: PrintWriter): ConsoleLogger = apply(ConsoleOut.printWriterOut(out))
-  def apply(out: ConsoleOut = ConsoleOut.systemOut, ansiCodesSupported: Boolean = formatEnabled,
-    useColor: Boolean = formatEnabled, suppressedMessage: SuppressedTraceContext => Option[String] = noSuppressedMessage): ConsoleLogger =
-    new ConsoleLogger(out, ansiCodesSupported, useColor, suppressedMessage)
+  def apply(out: PrintStream): ConsoleAppender = apply(generateName, ConsoleOut.printStreamOut(out))
+  def apply(out: PrintWriter): ConsoleAppender = apply(generateName, ConsoleOut.printWriterOut(out))
+  def apply(name: String = generateName, out: ConsoleOut = ConsoleOut.systemOut, ansiCodesSupported: Boolean = formatEnabled,
+    useColor: Boolean = formatEnabled, suppressedMessage: SuppressedTraceContext => Option[String] = noSuppressedMessage): ConsoleAppender =
+    {
+      val appender = new ConsoleAppender(name, out, ansiCodesSupported, useColor, suppressedMessage)
+      appender.start
+      appender
+    }
+  def generateName: String =
+    "out-" + generateId.incrementAndGet
+  private val generateId: AtomicInteger = new AtomicInteger
 
   private[this] val EscapeSequence = (27.toChar + "[^@-~]*[@-~]").r
   def stripEscapeSequences(s: String): String =
     EscapeSequence.pattern.matcher(s).replaceAll("")
+
+  def toLevel(level: XLevel): Level.Value =
+    level match {
+      case XLevel.OFF   => Level.Debug
+      case XLevel.FATAL => Level.Error
+      case XLevel.ERROR => Level.Error
+      case XLevel.WARN  => Level.Warn
+      case XLevel.INFO  => Level.Info
+      case XLevel.DEBUG => Level.Debug
+      case _            => Level.Debug
+    }
+  def toXLevel(level: Level.Value): XLevel =
+    level match {
+      case Level.Error => XLevel.ERROR
+      case Level.Warn  => XLevel.WARN
+      case Level.Info  => XLevel.INFO
+      case Level.Debug => XLevel.DEBUG
+    }
 }
 
+// See http://stackoverflow.com/questions/24205093/how-to-create-a-custom-appender-in-log4j2
+// for custom appender using Java.
+// http://logging.apache.org/log4j/2.x/manual/customconfig.html
+// https://logging.apache.org/log4j/2.x/log4j-core/apidocs/index.html
+
 /**
  * A logger that logs to the console.  On supported systems, the level labels are
  * colored.
  *
  * This logger is not thread-safe.
  */
-class ConsoleLogger private[ConsoleLogger] (val out: ConsoleOut, override val ansiCodesSupported: Boolean, val useColor: Boolean, val suppressedMessage: SuppressedTraceContext => Option[String]) extends BasicLogger {
+class ConsoleAppender private[ConsoleAppender] (
+  val name: String,
+  val out: ConsoleOut,
+  val ansiCodesSupported: Boolean,
+  val useColor: Boolean,
+  val suppressedMessage: SuppressedTraceContext => Option[String]
+) extends AbstractAppender(name, null, PatternLayout.createDefaultLayout(), true) {
   import scala.Console.{ BLUE, GREEN, RED, RESET, YELLOW }
+
+  def append(event: XLogEvent): Unit =
+    {
+      val level = ConsoleAppender.toLevel(event.getLevel)
+      val message = event.getMessage
+      val str = messageToString(message)
+      appendLog(level, str)
+    }
+
+  def messageToString(msg: Message): String =
+    msg match {
+      case p: ParameterizedMessage => p.getFormattedMessage
+      case r: RingBufferLogEvent   => r.getFormattedMessage
+      case o: ObjectMessage        => objectToString(o.getParameter)
+      case _                       => msg.toString
+    }
+  def objectToString(o: AnyRef): String =
+    o match {
+      case x: ChannelLogEntry => x.message
+      case _                  => o.toString
+    }
+
   def messageColor(level: Level.Value) = RESET
   def labelColor(level: Level.Value) =
     level match {
@@ -148,24 +262,29 @@ class ConsoleLogger private[ConsoleLogger] (val out: ConsoleOut, override val an
       case Level.Warn  => YELLOW
       case _           => RESET
     }
-  def successLabelColor = GREEN
-  def successMessageColor = RESET
-  override def success(message: => String): Unit = {
-    if (successEnabled)
-      log(successLabelColor, Level.SuccessLabel, successMessageColor, message)
+
+  // success is called by ConsoleLogger.
+  // This should turn into an event.
+  private[sbt] def success(message: => String): Unit = {
+    appendLog(successLabelColor, Level.SuccessLabel, successMessageColor, message)
   }
-  def trace(t: => Throwable): Unit =
+  private[sbt] def successLabelColor = GREEN
+  private[sbt] def successMessageColor = RESET
+
+  def trace(t: => Throwable, traceLevel: Int): Unit =
     out.lockObject.synchronized {
-      val traceLevel = getTrace
       if (traceLevel >= 0)
         out.print(StackTrace.trimmed(t, traceLevel))
       if (traceLevel <= 2)
         for (msg <- suppressedMessage(new SuppressedTraceContext(traceLevel, ansiCodesSupported && useColor)))
           printLabeledLine(labelColor(Level.Error), "trace", messageColor(Level.Error), msg)
     }
-  def log(level: Level.Value, message: => String): Unit = {
-    if (atLevel(level))
-      log(labelColor(level), level.toString, messageColor(level), message)
+
+  def control(event: ControlEvent.Value, message: => String): Unit =
+    appendLog(labelColor(Level.Info), Level.Info.toString, BLUE, message)
+
+  def appendLog(level: Level.Value, message: => String): Unit = {
+    appendLog(labelColor(level), level.toString, messageColor(level), message)
   }
   private def reset(): Unit = setColor(RESET)
 
@@ -173,7 +292,7 @@ class ConsoleLogger private[ConsoleLogger] (val out: ConsoleOut, override val an
     if (ansiCodesSupported && useColor)
       out.lockObject.synchronized { out.print(color) }
   }
-  private def log(labelColor: String, label: String, messageColor: String, message: String): Unit =
+  private def appendLog(labelColor: String, label: String, messageColor: String, message: String): Unit =
     out.lockObject.synchronized {
       for (line <- message.split("""\n"""))
         printLabeledLine(labelColor, label, messageColor, line)
@@ -189,10 +308,9 @@ class ConsoleLogger private[ConsoleLogger] (val out: ConsoleOut, override val an
       setColor(messageColor)
       out.print(line)
       reset()
+      out.print(s" ($name)")
       out.println()
     }
-
-  def logAll(events: Seq[LogEvent]) = out.lockObject.synchronized { events.foreach(log) }
-  def control(event: ControlEvent.Value, message: => String): Unit = log(labelColor(Level.Info), Level.Info.toString, BLUE, message)
 }
+
 final class SuppressedTraceContext(val traceLevel: Int, val useColor: Boolean)

internal/util-logging/src/main/scala/sbt/internal/util/ConsoleOut.scala

@@ -33,7 +33,7 @@ object ConsoleOut {
     def println(s: String): Unit = synchronized { current.append(s); println() }
     def println(): Unit = synchronized {
       val s = current.toString
-      if (ConsoleLogger.formatEnabled && last.exists(lmsg => f(s, lmsg)))
+      if (ConsoleAppender.formatEnabled && last.exists(lmsg => f(s, lmsg)))
         lockObject.print(OverwriteLine)
       lockObject.println(s)
       last = Some(s)

internal/util-logging/src/main/scala/sbt/internal/util/GlobalLogging.scala

@@ -5,6 +5,7 @@ package sbt.internal.util
 
 import sbt.util._
 import java.io.{ File, PrintWriter }
+import org.apache.logging.log4j.core.Appender
 
 /**
  * Provides the current global logging configuration.
@@ -15,7 +16,10 @@ import java.io.{ File, PrintWriter }
  * `backing` tracks the files that persist the global logging.
  * `newLogger` creates a new global logging configuration from a sink and backing configuration.
  */
-final case class GlobalLogging(full: Logger, console: ConsoleOut, backed: AbstractLogger, backing: GlobalLogBacking, newLogger: (PrintWriter, GlobalLogBacking) => GlobalLogging)
+final case class GlobalLogging(full: ManagedLogger, console: ConsoleOut, backed: Appender,
+  backing: GlobalLogBacking, newAppender: (ManagedLogger, PrintWriter, GlobalLogBacking) => GlobalLogging)
+
+final case class GlobalLogging1(full: Logger, console: ConsoleOut, backed: AbstractLogger, backing: GlobalLogBacking, newLogger: (PrintWriter, GlobalLogBacking) => GlobalLogging1)
 
 /**
  * Tracks the files that persist the global logging.
@@ -38,10 +42,28 @@ final case class GlobalLogBacking(file: File, last: Option[File], newBackingFile
 object GlobalLogBacking {
   def apply(newBackingFile: => File): GlobalLogBacking = GlobalLogBacking(newBackingFile, None, newBackingFile _)
 }
+
 object GlobalLogging {
-  def initial(newLogger: (PrintWriter, GlobalLogBacking) => GlobalLogging, newBackingFile: => File, console: ConsoleOut): GlobalLogging =
+  import java.util.concurrent.atomic.AtomicInteger
+  private def generateName: String =
+    "GlobalLogging" + generateId.incrementAndGet
+  private val generateId: AtomicInteger = new AtomicInteger
+
+  def initial1(newLogger: (PrintWriter, GlobalLogBacking) => GlobalLogging1, newBackingFile: => File, console: ConsoleOut): GlobalLogging1 =
     {
       val log = ConsoleLogger(console)
-      GlobalLogging(log, console, log, GlobalLogBacking(newBackingFile), newLogger)
+      GlobalLogging1(log, console, log, GlobalLogBacking(newBackingFile), newLogger)
     }
-}
+
+  def initial(newAppender: (ManagedLogger, PrintWriter, GlobalLogBacking) => GlobalLogging, newBackingFile: => File, console: ConsoleOut): GlobalLogging =
+    {
+      val loggerName = generateName
+      val log = LogExchange.logger(loggerName)
+      val appender = ConsoleAppender(ConsoleAppender.generateName, console)
+      LogExchange.bindLoggerAppenders(
+        loggerName, List(appender -> Level.Info)
+      )
+      GlobalLogging(log, console, appender, GlobalLogBacking(newBackingFile), newAppender)
+    }
+}
+

internal/util-logging/src/main/scala/sbt/internal/util/MainLogging.scala

@@ -2,42 +2,65 @@ package sbt.internal.util
 
 import sbt.util._
 import java.io.PrintWriter
+import org.apache.logging.log4j.core.Appender
 
-object MainLogging {
-  def multiLogger(config: MultiLoggerConfig): Logger =
+object MainAppender {
+  import java.util.concurrent.atomic.AtomicInteger
+  private def generateGlobalBackingName: String =
+    "GlobalBacking" + generateId.incrementAndGet
+  private val generateId: AtomicInteger = new AtomicInteger
+
+  def multiLogger(log: ManagedLogger, config: MainAppenderConfig): ManagedLogger =
     {
       import config._
-      val multi = new MultiLogger(console :: backed :: extra)
-      // sets multi to the most verbose for clients that inspect the current level
-      multi setLevel Level.unionAll(backingLevel :: screenLevel :: extra.map(_.getLevel))
-      // set the specific levels
-      console setLevel screenLevel
-      backed setLevel backingLevel
-      console setTrace screenTrace
-      backed setTrace backingTrace
-      multi: Logger
+      // TODO
+      // console setTrace screenTrace
+      // backed setTrace backingTrace
+      // multi: Logger
+
+      // val log = LogExchange.logger(loggerName)
+      LogExchange.unbindLoggerAppenders(log.name)
+      LogExchange.bindLoggerAppenders(
+        log.name,
+        (consoleOpt.toList map { _ -> screenLevel }) :::
+          List(backed -> backingLevel) :::
+          (extra map { x => (x -> Level.Info) })
+      )
+      log
     }
 
-  def globalDefault(console: ConsoleOut): (PrintWriter, GlobalLogBacking) => GlobalLogging =
+  def globalDefault(console: ConsoleOut): (ManagedLogger, PrintWriter, GlobalLogBacking) => GlobalLogging =
     {
-      lazy val f: (PrintWriter, GlobalLogBacking) => GlobalLogging = (writer, backing) => {
-        val backed = defaultBacked()(writer)
-        val full = multiLogger(defaultMultiConfig(console, backed))
-        GlobalLogging(full, console, backed, backing, f)
+      lazy val newAppender: (ManagedLogger, PrintWriter, GlobalLogBacking) => GlobalLogging = (log, writer, backing) => {
+        val backed: Appender = defaultBacked(generateGlobalBackingName)(writer)
+        val full = multiLogger(log, defaultMultiConfig(Option(console), backed, Nil))
+        GlobalLogging(full, console, backed, backing, newAppender)
       }
-      f
+      newAppender
     }
 
-  def defaultMultiConfig(console: ConsoleOut, backing: AbstractLogger): MultiLoggerConfig =
-    new MultiLoggerConfig(defaultScreen(console, ConsoleLogger.noSuppressedMessage), backing, Nil, Level.Info, Level.Debug, -1, Int.MaxValue)
+  def defaultMultiConfig(consoleOpt: Option[ConsoleOut], backing: Appender, extra: List[Appender]): MainAppenderConfig =
+    MainAppenderConfig(consoleOpt map { defaultScreen(_, ConsoleAppender.noSuppressedMessage) }, backing, extra,
+      Level.Info, Level.Debug, -1, Int.MaxValue)
+  def defaultScreen(console: ConsoleOut): Appender = ConsoleAppender(ConsoleAppender.generateName, console)
+  def defaultScreen(console: ConsoleOut, suppressedMessage: SuppressedTraceContext => Option[String]): Appender =
+    ConsoleAppender(ConsoleAppender.generateName, console, suppressedMessage = suppressedMessage)
+  def defaultScreen(name: String, console: ConsoleOut, suppressedMessage: SuppressedTraceContext => Option[String]): Appender =
+    ConsoleAppender(name, console, suppressedMessage = suppressedMessage)
 
-  def defaultScreen(console: ConsoleOut): AbstractLogger = ConsoleLogger(console)
-  def defaultScreen(console: ConsoleOut, suppressedMessage: SuppressedTraceContext => Option[String]): AbstractLogger =
-    ConsoleLogger(console, suppressedMessage = suppressedMessage)
+  def defaultBacked(
+    loggerName: String = generateGlobalBackingName,
+    useColor: Boolean = ConsoleAppender.formatEnabled
+  ): PrintWriter => Appender =
+    to => {
+      ConsoleAppender(
+        ConsoleAppender.generateName,
+        ConsoleOut.printWriterOut(to), useColor = useColor
+      )
+    }
 
-  def defaultBacked(useColor: Boolean = ConsoleLogger.formatEnabled): PrintWriter => ConsoleLogger =
-    to => ConsoleLogger(ConsoleOut.printWriterOut(to), useColor = useColor)
+  final case class MainAppenderConfig(
+    consoleOpt: Option[Appender], backed: Appender, extra: List[Appender],
+    screenLevel: Level.Value, backingLevel: Level.Value, screenTrace: Int, backingTrace: Int
+  )
 }
-
-final case class MultiLoggerConfig(console: AbstractLogger, backed: AbstractLogger, extra: List[AbstractLogger],
-  screenLevel: Level.Value, backingLevel: Level.Value, screenTrace: Int, backingTrace: Int)

internal/util-logging/src/main/scala/sbt/internal/util/ManagedLogger.scala

@@ -0,0 +1,25 @@
+package sbt.internal.util
+
+import sbt.util._
+import org.apache.logging.log4j.{ Logger => XLogger }
+import org.apache.logging.log4j.message.ObjectMessage
+
+/**
+ * Delegates log events to the associated LogExchange.
+ */
+class ManagedLogger(
+  val name: String,
+  val channelName: Option[String],
+  val execId: Option[String],
+  xlogger: XLogger
+) extends Logger {
+  override def trace(t: => Throwable): Unit = () // exchange.appendLog(new Trace(t))
+  override def log(level: Level.Value, message: => String): Unit =
+    {
+      xlogger.log(
+        ConsoleAppender.toXLevel(level),
+        new ObjectMessage(ChannelLogEntry(level.toString, message, channelName, execId))
+      )
+    }
+  override def success(message: => String): Unit = xlogger.info(message)
+}

internal/util-logging/src/main/scala/sbt/internal/util/MultiLogger.scala

@@ -41,7 +41,7 @@ class MultiLogger(delegates: List[AbstractLogger]) extends BasicLogger {
 
   private[this] def removeEscapes(event: LogEvent): LogEvent =
     {
-      import ConsoleLogger.{ removeEscapeSequences => rm }
+      import ConsoleAppender.{ removeEscapeSequences => rm }
       event match {
         case s: Success => new Success(rm(s.msg))
         case l: Log => new Log(l.level, rm(l.msg))

internal/util-logging/src/main/scala/sbt/util/LogExchange.scala

@@ -0,0 +1,75 @@
+package sbt.util
+
+import sbt.internal.util._
+import org.apache.logging.log4j.{ LogManager => XLogManager, Level => XLevel }
+import org.apache.logging.log4j.core._
+import org.apache.logging.log4j.core.appender.AsyncAppender
+import org.apache.logging.log4j.core.config.{ AppenderRef, LoggerConfig }
+import scala.collection.JavaConverters._
+
+// http://logging.apache.org/log4j/2.x/manual/customconfig.html
+// https://logging.apache.org/log4j/2.x/log4j-core/apidocs/index.html
+
+sealed abstract class LogExchange {
+  private[sbt] lazy val context: LoggerContext = init()
+  private[sbt] lazy val asyncStdout: AsyncAppender = buildAsyncStdout
+
+  def logger(name: String): ManagedLogger = logger(name, None, None)
+  def logger(name: String, channelName: Option[String], execId: Option[String]): ManagedLogger = {
+    val _ = context
+    val ctx = XLogManager.getContext(false) match { case x: LoggerContext => x }
+    val config = ctx.getConfiguration
+    val loggerConfig = LoggerConfig.createLogger(false, XLevel.DEBUG, name,
+      "true", Array[AppenderRef](), null, config, null)
+    config.addLogger(name, loggerConfig)
+    ctx.updateLoggers
+    val logger = ctx.getLogger(name)
+    new ManagedLogger(name, channelName, execId, logger)
+  }
+  def unbindLoggerAppenders(loggerName: String): Unit = {
+    val lc = loggerConfig(loggerName)
+    lc.getAppenders.asScala foreach {
+      case (k, v) => lc.removeAppender(k)
+    }
+  }
+  def bindLoggerAppenders(loggerName: String, appenders: List[(Appender, Level.Value)]): Unit = {
+    val lc = loggerConfig(loggerName)
+    appenders foreach {
+      case (x, lv) => lc.addAppender(x, ConsoleAppender.toXLevel(lv), null)
+    }
+  }
+  def loggerConfig(loggerName: String): LoggerConfig = {
+    val ctx = XLogManager.getContext(false) match { case x: LoggerContext => x }
+    val config = ctx.getConfiguration
+    config.getLoggerConfig(loggerName)
+  }
+  private[sbt] def buildAsyncStdout: AsyncAppender = {
+    val ctx = XLogManager.getContext(false) match { case x: LoggerContext => x }
+    val config = ctx.getConfiguration
+    // val layout = PatternLayout.newBuilder
+    //   .withPattern(PatternLayout.SIMPLE_CONVERSION_PATTERN)
+    //   .build
+    val appender = ConsoleAppender("Stdout")
+    // CustomConsoleAppenderImpl.createAppender("Stdout", layout, null, null)
+    appender.start
+    config.addAppender(appender)
+    val asyncAppender: AsyncAppender = (AsyncAppender.newBuilder(): AsyncAppender.Builder)
+      .setName("AsyncStdout")
+      .setAppenderRefs(Array(AppenderRef.createAppenderRef("Stdout", XLevel.DEBUG, null)))
+      .setBlocking(false)
+      .setConfiguration(config)
+      .build
+    asyncAppender.start
+    config.addAppender(asyncAppender)
+    asyncAppender
+  }
+  private[sbt] def init(): LoggerContext = {
+    import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory
+    import org.apache.logging.log4j.core.config.Configurator
+    val builder = ConfigurationBuilderFactory.newConfigurationBuilder
+    builder.setConfigurationName("sbt.util.logging")
+    val ctx = Configurator.initialize(builder.build())
+    ctx match { case x: LoggerContext => x }
+  }
+}
+object LogExchange extends LogExchange

internal/util-logging/src/test/resources/log4j2.component.properties

@@ -0,0 +1 @@
+Log4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector

internal/util-logging/src/test/scala/Escapes.scala

@@ -4,7 +4,7 @@ import org.scalacheck._
 import Prop._
 import Gen.{ listOf, oneOf }
 
-import ConsoleLogger.{ ESC, hasEscapeSequence, isEscapeTerminator, removeEscapeSequences }
+import ConsoleAppender.{ ESC, hasEscapeSequence, isEscapeTerminator, removeEscapeSequences }
 
 object Escapes extends Properties("Escapes") {
   property("genTerminator only generates terminators") =

internal/util-logging/src/test/scala/ManagedLoggerSpec.scala

@@ -0,0 +1,52 @@
+package sbt.internal.util
+
+import org.scalatest._
+import sbt.util._
+import java.io.{ File, PrintWriter }
+import sbt.io.Using
+
+class ManagedLoggerSpec extends FlatSpec with Matchers {
+  "ManagedLogger" should "log to console" in {
+    val log = LogExchange.logger("foo")
+    LogExchange.bindLoggerAppenders("foo", List(LogExchange.asyncStdout -> Level.Info))
+    log.info("test")
+    log.debug("test")
+  }
+
+  "global logging" should "log immediately after initialization" in {
+    // this is passed into State normally
+    val global0 = initialGlobalLogging
+    val full = global0.full
+    (1 to 3).toList foreach { x => full.info(s"test$x") }
+  }
+
+  // This is done in Mainloop.scala
+  it should "create a new backing with newAppender" in {
+    val global0 = initialGlobalLogging
+    val logBacking0 = global0.backing
+    val global1 = Using.fileWriter(append = true)(logBacking0.file) { writer =>
+      val out = new PrintWriter(writer)
+      val g = global0.newAppender(global0.full, out, logBacking0)
+      val full = g.full
+      (1 to 3).toList foreach { x => full.info(s"newAppender $x") }
+      assert(logBacking0.file.exists)
+      g
+    }
+    val logBacking1 = global1.backing
+    Using.fileWriter(append = true)(logBacking1.file) { writer =>
+      val out = new PrintWriter(writer)
+      val g = global1.newAppender(global1.full, out, logBacking1)
+      val full = g.full
+      (1 to 3).toList foreach { x => full.info(s"newAppender $x") }
+      // println(logBacking.file)
+      // print("Press enter to continue. ")
+      // System.console.readLine
+      assert(logBacking1.file.exists)
+    }
+  }
+
+  val console = ConsoleOut.systemOut
+  def initialGlobalLogging: GlobalLogging = GlobalLogging.initial(
+    MainAppender.globalDefault(console), File.createTempFile("sbt", ".log"), console
+  )
+}

project/Dependencies.scala

@@ -35,10 +35,15 @@ object Dependencies {
 
   val scalaCheck = "org.scalacheck" %% "scalacheck" % "1.13.4"
   val scalatest = "org.scalatest" %% "scalatest" % "3.0.1"
-
   val parserCombinator211 = "org.scala-lang.modules" %% "scala-parser-combinators" % "1.0.4"
 
   val sjsonnewVersion = "0.7.0"
   val sjsonnew = "com.eed3si9n" %% "sjson-new-core" % sjsonnewVersion
   val sjsonnewScalaJson = "com.eed3si9n" %% "sjson-new-scalajson" % sjsonnewVersion
+
+  def log4jVersion = "2.7"
+  val log4jApi = "org.apache.logging.log4j" % "log4j-api" % log4jVersion
+  val log4jCore = "org.apache.logging.log4j" % "log4j-core" % log4jVersion
+  val log4jSlf4jImpl = "org.apache.logging.log4j" % "log4j-slf4j-impl" % log4jVersion
+  val disruptor = "com.lmax" % "disruptor" % "3.3.6"
 }

project/contraband.sbt

@@ -0,0 +1 @@
+addSbtPlugin("org.scala-sbt" % "sbt-contraband" % "0.3.0-M3")