[SPARK-11929][CORE] Make the repl log4j configuration override the root logger.

In the default Spark distribution, there are currently two separate
log4j config files, with different default values for the root logger,
so that when running the shell you have a different default log level.
This makes the shell more usable, since the logs don't overwhelm the
output.

But if you install a custom log4j.properties, you lose that, because
then it's going to be used no matter whether you're running a regular
app or the shell.

With this change, the overriding of the log level is done differently;
the log level repl's main class (org.apache.spark.repl.Main) is used
to define the root logger's level when running the shell, defaulting
to WARN if it's not set explicitly.

On a somewhat related change, the shell output about the "sc" variable
was changed a bit to contain a little more useful information about
the application, since when the root logger's log level is WARN, that
information is never shown to the user.

Author: Marcelo Vanzin <[email protected]>

Closes #9816 from vanzin/shell-logging.

Author: Marcelo Vanzin

conf/log4j.properties.template

@@ -22,6 +22,11 @@ log4j.appender.console.target=System.err
 log4j.appender.console.layout=org.apache.log4j.PatternLayout
 log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss} %p %c{1}: %m%n
 
+# Set the default spark-shell log level to WARN. When running the spark-shell, the
+# log level for this class is used to overwrite the root logger's log level, so that
+# the user can have different defaults for the shell and regular Spark apps.
+log4j.logger.org.apache.spark.repl.Main=WARN
+
 # Settings to quiet third party logs that are too verbose
 log4j.logger.org.spark-project.jetty=WARN
 log4j.logger.org.spark-project.jetty.util.component.AbstractLifeCycle=ERROR

core/src/main/resources/org/apache/spark/log4j-defaults-repl.properties

@@ -22,6 +22,11 @@ log4j.appender.console.target=System.err
 log4j.appender.console.layout=org.apache.log4j.PatternLayout
 log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss} %p %c{1}: %m%n
 
+# Set the default spark-shell log level to WARN. When running the spark-shell, the
+# log level for this class is used to overwrite the root logger's log level, so that
+# the user can have different defaults for the shell and regular Spark apps.
+log4j.logger.org.apache.spark.repl.Main=WARN
+
 # Settings to quiet third party logs that are too verbose
 log4j.logger.org.spark-project.jetty=WARN
 log4j.logger.org.spark-project.jetty.util.component.AbstractLifeCycle=ERROR

core/src/main/resources/org/apache/spark/log4j-defaults.properties

@@ -17,7 +17,7 @@
 
 package org.apache.spark
 
-import org.apache.log4j.{LogManager, PropertyConfigurator}
+import org.apache.log4j.{Level, LogManager, PropertyConfigurator}
 import org.slf4j.{Logger, LoggerFactory}
 import org.slf4j.impl.StaticLoggerBinder
 
@@ -119,30 +119,31 @@ trait Logging {
     val usingLog4j12 = "org.slf4j.impl.Log4jLoggerFactory".equals(binderClass)
     if (usingLog4j12) {
       val log4j12Initialized = LogManager.getRootLogger.getAllAppenders.hasMoreElements
+      // scalastyle:off println
       if (!log4j12Initialized) {
-        // scalastyle:off println
-        if (Utils.isInInterpreter) {
-          val replDefaultLogProps = "org/apache/spark/log4j-defaults-repl.properties"
-          Option(Utils.getSparkClassLoader.getResource(replDefaultLogProps)) match {
-            case Some(url) =>
-              PropertyConfigurator.configure(url)
-              System.err.println(s"Using Spark's repl log4j profile: $replDefaultLogProps")
-              System.err.println("To adjust logging level use sc.setLogLevel(\"INFO\")")
-            case None =>
-              System.err.println(s"Spark was unable to load $replDefaultLogProps")
-          }
-        } else {
-          val defaultLogProps = "org/apache/spark/log4j-defaults.properties"
-          Option(Utils.getSparkClassLoader.getResource(defaultLogProps)) match {
-            case Some(url) =>
-              PropertyConfigurator.configure(url)
-              System.err.println(s"Using Spark's default log4j profile: $defaultLogProps")
-            case None =>
-              System.err.println(s"Spark was unable to load $defaultLogProps")
-          }
+        val defaultLogProps = "org/apache/spark/log4j-defaults.properties"
+        Option(Utils.getSparkClassLoader.getResource(defaultLogProps)) match {
+          case Some(url) =>
+            PropertyConfigurator.configure(url)
+            System.err.println(s"Using Spark's default log4j profile: $defaultLogProps")
+          case None =>
+            System.err.println(s"Spark was unable to load $defaultLogProps")
         }
-        // scalastyle:on println
       }
+
+      if (Utils.isInInterpreter) {
+        // Use the repl's main class to define the default log level when running the shell,
+        // overriding the root logger's config if they're different.
+        val rootLogger = LogManager.getRootLogger()
+        val replLogger = LogManager.getLogger("org.apache.spark.repl.Main")
+        val replLevel = Option(replLogger.getLevel()).getOrElse(Level.WARN)
+        if (replLevel != rootLogger.getEffectiveLevel()) {
+          System.err.printf("Setting default log level to \"%s\".\n", replLevel)
+          System.err.println("To adjust logging level use sc.setLogLevel(newLevel).")
+          rootLogger.setLevel(replLevel)
+        }
+      }
+      // scalastyle:on println
     }
     Logging.initialized = true
 

core/src/main/scala/org/apache/spark/Logging.scala

@@ -123,18 +123,19 @@ private[repl] trait SparkILoopInit {
   def initializeSpark() {
     intp.beQuietDuring {
       command("""
-         @transient val sc = {
-           val _sc = org.apache.spark.repl.Main.interp.createSparkContext()
-           println("Spark context available as sc.")
-           _sc
-         }
+        @transient val sc = {
+          val _sc = org.apache.spark.repl.Main.interp.createSparkContext()
+          println("Spark context available as sc " +
+            s"(master = ${_sc.master}, app id = ${_sc.applicationId}).")
+          _sc
+        }
         """)
       command("""
-         @transient val sqlContext = {
-           val _sqlContext = org.apache.spark.repl.Main.interp.createSQLContext()
-           println("SQL context available as sqlContext.")
-           _sqlContext
-         }
+        @transient val sqlContext = {
+          val _sqlContext = org.apache.spark.repl.Main.interp.createSQLContext()
+          println("SQL context available as sqlContext.")
+          _sqlContext
+        }
         """)
       command("import org.apache.spark.SparkContext._")
       command("import sqlContext.implicits._")

repl/scala-2.10/src/main/scala/org/apache/spark/repl/SparkILoopInit.scala

@@ -37,18 +37,19 @@ class SparkILoop(in0: Option[BufferedReader], out: JPrintWriter)
   def initializeSpark() {
     intp.beQuietDuring {
       processLine("""
-         @transient val sc = {
-           val _sc = org.apache.spark.repl.Main.createSparkContext()
-           println("Spark context available as sc.")
-           _sc
-         }
+        @transient val sc = {
+          val _sc = org.apache.spark.repl.Main.createSparkContext()
+          println("Spark context available as sc " +
+            s"(master = ${_sc.master}, app id = ${_sc.applicationId}).")
+          _sc
+        }
         """)
       processLine("""
-         @transient val sqlContext = {
-           val _sqlContext = org.apache.spark.repl.Main.createSQLContext()
-           println("SQL context available as sqlContext.")
-           _sqlContext
-         }
+        @transient val sqlContext = {
+          val _sqlContext = org.apache.spark.repl.Main.createSQLContext()
+          println("SQL context available as sqlContext.")
+          _sqlContext
+        }
         """)
       processLine("import org.apache.spark.SparkContext._")
       processLine("import sqlContext.implicits._")
@@ -85,7 +86,7 @@ class SparkILoop(in0: Option[BufferedReader], out: JPrintWriter)
   /** Available commands */
   override def commands: List[LoopCommand] = sparkStandardCommands
 
-  /** 
+  /**
    * We override `loadFiles` because we need to initialize Spark *before* the REPL
    * sees any files, so that the Spark context is visible in those files. This is a bit of a
    * hack, but there isn't another hook available to us at this point.
@@ -98,7 +99,7 @@ class SparkILoop(in0: Option[BufferedReader], out: JPrintWriter)
 
 object SparkILoop {
 
-  /** 
+  /**
    * Creates an interpreter loop with default settings and feeds
    * the given code to it as input.
    */