[SPARK-23820][CORE] Enable use of long form of callsite in logs

This adds an option to event logging to include the long form of the callsite instead of the short form.

Author: Michael Mior <mmior@uwaterloo.ca>

Closes #21433 from michaelmior/long-callsite.

core/src/main/scala/org/apache/spark/internal/config/package.scala

@@ -72,6 +72,9 @@ package object config {
   private[spark] val EVENT_LOG_OVERWRITE =
     ConfigBuilder("spark.eventLog.overwrite").booleanConf.createWithDefault(false)
 
+  private[spark] val EVENT_LOG_CALLSITE_FORM =
+    ConfigBuilder("spark.eventLog.callsite").stringConf.createWithDefault("short")
+
   private[spark] val EXECUTOR_CLASS_PATH =
     ConfigBuilder(SparkLauncher.EXECUTOR_EXTRA_CLASSPATH).stringConf.createOptional
 

core/src/main/scala/org/apache/spark/storage/RDDInfo.scala

@@ -17,7 +17,9 @@
 
 package org.apache.spark.storage
 
+import org.apache.spark.SparkEnv
 import org.apache.spark.annotation.DeveloperApi
+import org.apache.spark.internal.config._
 import org.apache.spark.rdd.{RDD, RDDOperationScope}
 import org.apache.spark.util.Utils
 
@@ -53,10 +55,16 @@ class RDDInfo(
 }
 
 private[spark] object RDDInfo {
+  private val callsiteForm = SparkEnv.get.conf.get(EVENT_LOG_CALLSITE_FORM)
+
   def fromRdd(rdd: RDD[_]): RDDInfo = {
     val rddName = Option(rdd.name).getOrElse(Utils.getFormattedClassName(rdd))
     val parentIds = rdd.dependencies.map(_.rdd.id)
+    val callSite = callsiteForm match {
+      case "short" => rdd.creationSite.shortForm
+      case "long" => rdd.creationSite.longForm
+    }
     new RDDInfo(rdd.id, rddName, rdd.partitions.length,
-      rdd.getStorageLevel, parentIds, rdd.creationSite.shortForm, rdd.scope)
+      rdd.getStorageLevel, parentIds, callSite, rdd.scope)
   }
 }