[HOTFIX][Streaming][MLlib] use temp folder for checkpoint

or Jenkins will complain about no Apache header in checkpoint files. tdas rxin

Author: Xiangrui Meng <meng@databricks.com>

Closes #2046 from mengxr/tmp-checkpoint and squashes the following commits:

0d3ec73 [Xiangrui Meng] remove ssc.stop
9797843 [Xiangrui Meng] change checkpointDir to lazy val
89964ab [Xiangrui Meng] use temp folder for checkpoint

(cherry picked from commit fce5c0f)
Signed-off-by: Xiangrui Meng <meng@databricks.com>

Author: mengxr

mllib/src/test/scala/org/apache/spark/mllib/regression/StreamingLinearRegressionSuite.scala

@@ -49,7 +49,6 @@ class StreamingLinearRegressionSuite extends FunSuite with TestSuiteBase {
 
   // Test if we can accurately learn Y = 10*X1 + 10*X2 on streaming data
   test("parameter accuracy") {
-
     // create model
     val model = new StreamingLinearRegressionWithSGD()
       .setInitialWeights(Vectors.dense(0.0, 0.0))
@@ -82,7 +81,6 @@ class StreamingLinearRegressionSuite extends FunSuite with TestSuiteBase {
 
   // Test that parameter estimates improve when learning Y = 10*X1 on streaming data
   test("parameter convergence") {
-
     // create model
     val model = new StreamingLinearRegressionWithSGD()
       .setInitialWeights(Vectors.dense(0.0))
@@ -113,12 +111,10 @@ class StreamingLinearRegressionSuite extends FunSuite with TestSuiteBase {
     assert(deltas.forall(x => (x._1 - x._2) <= 0.1))
     // check that error shrunk on at least 2 batches
     assert(deltas.map(x => if ((x._1 - x._2) < 0) 1 else 0).sum > 1)
-
   }
 
   // Test predictions on a stream
   test("predictions") {
-
     // create model initialized with true weights
     val model = new StreamingLinearRegressionWithSGD()
       .setInitialWeights(Vectors.dense(10.0, 10.0))
@@ -142,7 +138,5 @@ class StreamingLinearRegressionSuite extends FunSuite with TestSuiteBase {
     // compute the mean absolute error and check that it's always less than 0.1
     val errors = output.map(batch => batch.map(p => math.abs(p._1 - p._2)).sum / nPoints)
     assert(errors.forall(x => x <= 0.1))
-
   }
-
 }

streaming/src/test/scala/org/apache/spark/streaming/TestSuiteBase.scala

@@ -17,18 +17,18 @@
 
 package org.apache.spark.streaming
 
-import org.apache.spark.streaming.dstream.{DStream, InputDStream, ForEachDStream}
-import org.apache.spark.streaming.util.ManualClock
+import java.io.{ObjectInputStream, IOException}
 
 import scala.collection.mutable.ArrayBuffer
 import scala.collection.mutable.SynchronizedBuffer
 import scala.reflect.ClassTag
 
-import java.io.{ObjectInputStream, IOException}
-
 import org.scalatest.{BeforeAndAfter, FunSuite}
+import com.google.common.io.Files
 
-import org.apache.spark.{SparkContext, SparkConf, Logging}
+import org.apache.spark.streaming.dstream.{DStream, InputDStream, ForEachDStream}
+import org.apache.spark.streaming.util.ManualClock
+import org.apache.spark.{SparkConf, Logging}
 import org.apache.spark.rdd.RDD
 
 /**
@@ -119,7 +119,12 @@ trait TestSuiteBase extends FunSuite with BeforeAndAfter with Logging {
   def batchDuration = Seconds(1)
 
   // Directory where the checkpoint data will be saved
-  def checkpointDir = "checkpoint"
+  lazy val checkpointDir = {
+    val dir = Files.createTempDir()
+    logDebug(s"checkpointDir: $dir")
+    dir.deleteOnExit()
+    dir.toString
+  }
 
   // Number of partitions of the input parallel collections created for testing
   def numInputPartitions = 2