Merge pull request #210 from haitaoyao/http-timeout

add http timeout for httpbroadcast

While pulling task bytecode from HttpBroadcast server, there's no timeout value set. This may cause spark executor code hang and other task in the same executor process wait for the lock. I have encountered the issue in my cluster. Here's the stacktrace I captured  : https://gist.github.com/haitaoyao/7655830

So add a time out value to ensure the task fail fast.

core/src/main/scala/org/apache/spark/broadcast/HttpBroadcast.scala

@@ -19,6 +19,7 @@ package org.apache.spark.broadcast
 
 import java.io.{File, FileOutputStream, ObjectInputStream, OutputStream}
 import java.net.URL
+import java.util.concurrent.TimeUnit
 
 import it.unimi.dsi.fastutil.io.FastBufferedInputStream
 import it.unimi.dsi.fastutil.io.FastBufferedOutputStream
@@ -83,6 +84,8 @@ private object HttpBroadcast extends Logging {
   private val files = new TimeStampedHashSet[String]
   private val cleaner = new MetadataCleaner(MetadataCleanerType.HTTP_BROADCAST, cleanup)
 
+  private val httpReadTimeout = TimeUnit.MILLISECONDS.convert(5,TimeUnit.MINUTES).toInt
+
   private lazy val compressionCodec = CompressionCodec.createCodec()
 
   def initialize(isDriver: Boolean) {
@@ -138,10 +141,13 @@ private object HttpBroadcast extends Logging {
   def read[T](id: Long): T = {
     val url = serverUri + "/" + BroadcastBlockId(id).name
     val in = {
+      val httpConnection = new URL(url).openConnection()
+      httpConnection.setReadTimeout(httpReadTimeout)
+      val inputStream = httpConnection.getInputStream()
       if (compress) {
-        compressionCodec.compressedInputStream(new URL(url).openStream())
+        compressionCodec.compressedInputStream(inputStream)
       } else {
-        new FastBufferedInputStream(new URL(url).openStream(), bufferSize)
+        new FastBufferedInputStream(inputStream, bufferSize)
       }
     }
     val ser = SparkEnv.get.serializer.newInstance()