SPARK-2035: Store call stack for stages, display it on the UI.

I'm not sure about the test -- I get a lot of unrelated failures for some reason. I'll try to sort it out. But hopefully the automation will test this for me if I send a pull request :).

I'll attach a demo HTML in [Jira](https://issues.apache.org/jira/browse/SPARK-2035).

Author: Daniel Darabos <darabos.daniel@gmail.com>
Author: Patrick Wendell <pwendell@gmail.com>

Closes #981 from darabos/darabos-call-stack and squashes the following commits:

f7c6bfa [Daniel Darabos] Fix bad merge. I undid 83c226d454 by Doris.
3d0a48d [Daniel Darabos] Merge remote-tracking branch 'upstream/master' into darabos-call-stack
b857849 [Daniel Darabos] Style: Break long line.
ecb5690 [Daniel Darabos] Include the last Spark method in the full stack trace. Otherwise it is not visible if the stage name is overridden.
d00a85b [Patrick Wendell] Make call sites for stages non-optional and well defined
b9eba24 [Daniel Darabos] Make StageInfo.details non-optional. Add JSON serialization code for the new field. Verify JSON backward compatibility.
4312828 [Daniel Darabos] Remove Mima excludes for CallSite. They should be unnecessary now, with SPARK-2070 fixed.
0920750 [Daniel Darabos] Merge remote-tracking branch 'upstream/master' into darabos-call-stack
a4b1faf [Daniel Darabos] Add Mima exclusions for the CallSite changes it has picked up. They are private methods/classes, so we ought to be safe.
932f810 [Daniel Darabos] Use empty CallSite instead of null in DAGSchedulerSuite. Outside of testing, this parameter always originates in SparkContext.scala, and will never be null.
ccd89d1 [Daniel Darabos] Fix long lines.
ac173e4 [Daniel Darabos] Hide "show details" if there are no details to show.
6182da6 [Daniel Darabos] Set a configurable limit on maximum call stack depth. It can be useful in memory-constrained situations with large numbers of stages.
8fe2e34 [Daniel Darabos] Store call stack for stages, display it on the UI.

4 files changed, 20 insertions, 7 deletions

diff --git a/core/src/test/scala/org/apache/spark/SparkContextInfoSuite.scala b/core/src/test/scala/org/apache/spark/SparkContextInfoSuite.scala
index cd3887dcc7..1fde4badda 100644
--- a/core/src/test/scala/org/apache/spark/SparkContextInfoSuite.scala
+++ b/core/src/test/scala/org/apache/spark/SparkContextInfoSuite.scala
@@ -70,7 +70,7 @@ package object testPackage extends Assertions {
   def runCallSiteTest(sc: SparkContext) {
     val rdd = sc.makeRDD(Array(1, 2, 3, 4), 2)
     val rddCreationSite = rdd.getCreationSite
-    val curCallSite = sc.getCallSite() // note: 2 lines after definition of "rdd"
+    val curCallSite = sc.getCallSite().short // note: 2 lines after definition of "rdd"
 
     val rddCreationLine = rddCreationSite match {
       case CALL_SITE_REGEX(func, file, line) => {
diff --git a/core/src/test/scala/org/apache/spark/scheduler/DAGSchedulerSuite.scala b/core/src/test/scala/org/apache/spark/scheduler/DAGSchedulerSuite.scala
index 7506d56d7e..4536832829 100644
--- a/core/src/test/scala/org/apache/spark/scheduler/DAGSchedulerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/scheduler/DAGSchedulerSuite.scala
@@ -29,6 +29,7 @@ import org.apache.spark._
 import org.apache.spark.rdd.RDD
 import org.apache.spark.scheduler.SchedulingMode.SchedulingMode
 import org.apache.spark.storage.{BlockId, BlockManagerId, BlockManagerMaster}
+import org.apache.spark.util.CallSite
 
 class BuggyDAGEventProcessActor extends Actor {
   val state = 0
@@ -211,7 +212,7 @@ class DAGSchedulerSuite extends TestKit(ActorSystem("DAGSchedulerSuite")) with F
       allowLocal: Boolean = false,
       listener: JobListener = jobListener): Int = {
     val jobId = scheduler.nextJobId.getAndIncrement()
-    runEvent(JobSubmitted(jobId, rdd, func, partitions, allowLocal, null, listener))
+    runEvent(JobSubmitted(jobId, rdd, func, partitions, allowLocal, CallSite("", ""), listener))
     jobId
   }
 
@@ -251,7 +252,7 @@ class DAGSchedulerSuite extends TestKit(ActorSystem("DAGSchedulerSuite")) with F
       override def toString = "DAGSchedulerSuite Local RDD"
     }
     val jobId = scheduler.nextJobId.getAndIncrement()
-    runEvent(JobSubmitted(jobId, rdd, jobComputeFunc, Array(0), true, null, jobListener))
+    runEvent(JobSubmitted(jobId, rdd, jobComputeFunc, Array(0), true, CallSite("", ""), jobListener))
     assert(results === Map(0 -> 42))
     assertDataStructuresEmpty
   }
@@ -265,7 +266,7 @@ class DAGSchedulerSuite extends TestKit(ActorSystem("DAGSchedulerSuite")) with F
       override def toString = "DAGSchedulerSuite Local RDD"
     }
     val jobId = scheduler.nextJobId.getAndIncrement()
-    runEvent(JobSubmitted(jobId, rdd, jobComputeFunc, Array(0), true, null, jobListener))
+    runEvent(JobSubmitted(jobId, rdd, jobComputeFunc, Array(0), true, CallSite("", ""), jobListener))
     assert(results.size == 0)
     assertDataStructuresEmpty
   }
diff --git a/core/src/test/scala/org/apache/spark/ui/jobs/JobProgressListenerSuite.scala b/core/src/test/scala/org/apache/spark/ui/jobs/JobProgressListenerSuite.scala
index 91b4c7b0dd..c3a14f48de 100644
--- a/core/src/test/scala/org/apache/spark/ui/jobs/JobProgressListenerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/ui/jobs/JobProgressListenerSuite.scala
@@ -32,12 +32,12 @@ class JobProgressListenerSuite extends FunSuite with LocalSparkContext with Matc
     val listener = new JobProgressListener(conf)
 
     def createStageStartEvent(stageId: Int) = {
-      val stageInfo = new StageInfo(stageId, stageId.toString, 0, null)
+      val stageInfo = new StageInfo(stageId, stageId.toString, 0, null, "")
       SparkListenerStageSubmitted(stageInfo)
     }
 
     def createStageEndEvent(stageId: Int) = {
-      val stageInfo = new StageInfo(stageId, stageId.toString, 0, null)
+      val stageInfo = new StageInfo(stageId, stageId.toString, 0, null, "")
       SparkListenerStageCompleted(stageInfo)
     }
 
diff --git a/core/src/test/scala/org/apache/spark/util/JsonProtocolSuite.scala b/core/src/test/scala/org/apache/spark/util/JsonProtocolSuite.scala
index 3031015256..f72389b6b3 100644
--- a/core/src/test/scala/org/apache/spark/util/JsonProtocolSuite.scala
+++ b/core/src/test/scala/org/apache/spark/util/JsonProtocolSuite.scala
@@ -117,6 +117,17 @@ class JsonProtocolSuite extends FunSuite {
     testBlockId(StreamBlockId(1, 2L))
   }
 
+  test("Backward compatibility") {
+    // StageInfo.details was added after 1.0.0.
+    val info = makeStageInfo(1, 2, 3, 4L, 5L)
+    assert(info.details.nonEmpty)
+    val newJson = JsonProtocol.stageInfoToJson(info)
+    val oldJson = newJson.removeField { case (field, _) => field == "Details" }
+    val newInfo = JsonProtocol.stageInfoFromJson(oldJson)
+    assert(info.name === newInfo.name)
+    assert("" === newInfo.details)
+  }
+
 
   /** -------------------------- *
    | Helper test running methods |
@@ -235,6 +246,7 @@ class JsonProtocolSuite extends FunSuite {
     (0 until info1.rddInfos.size).foreach { i =>
       assertEquals(info1.rddInfos(i), info2.rddInfos(i))
     }
+    assert(info1.details === info2.details)
   }
 
   private def assertEquals(info1: RDDInfo, info2: RDDInfo) {
@@ -438,7 +450,7 @@ class JsonProtocolSuite extends FunSuite {
 
   private def makeStageInfo(a: Int, b: Int, c: Int, d: Long, e: Long) = {
     val rddInfos = (1 to a % 5).map { i => makeRddInfo(a % i, b % i, c % i, d % i, e % i) }
-    new StageInfo(a, "greetings", b, rddInfos)
+    new StageInfo(a, "greetings", b, rddInfos, "details")
   }
 
   private def makeTaskInfo(a: Long, b: Int, c: Long) = {