Merge pull request #490 from woggling/conn-death

Detect when SendingConnections disconnect even if we aren't sending to them

core/src/main/scala/spark/network/Connection.scala

@@ -198,7 +198,7 @@ extends Connection(SocketChannel.open, selector_, remoteId_) {
     outbox.synchronized {
       outbox.addMessage(message)
       if (channel.isConnected) {
-        changeConnectionKeyInterest(SelectionKey.OP_WRITE)
+        changeConnectionKeyInterest(SelectionKey.OP_WRITE | SelectionKey.OP_READ)
       }
     }
   }
@@ -219,7 +219,7 @@ extends Connection(SocketChannel.open, selector_, remoteId_) {
   def finishConnect() {
     try {
       channel.finishConnect
-      changeConnectionKeyInterest(SelectionKey.OP_WRITE)
+      changeConnectionKeyInterest(SelectionKey.OP_WRITE | SelectionKey.OP_READ)
       logInfo("Connected to [" + address + "], " + outbox.messages.size + " messages pending")
     } catch {
       case e: Exception => {
@@ -239,8 +239,7 @@ extends Connection(SocketChannel.open, selector_, remoteId_) {
                 currentBuffers ++= chunk.buffers 
               }
               case None => {
-                changeConnectionKeyInterest(0)
-                /*key.interestOps(0)*/
+                changeConnectionKeyInterest(SelectionKey.OP_READ)
                 return
               }
             }
@@ -267,6 +266,23 @@ extends Connection(SocketChannel.open, selector_, remoteId_) {
       }
     }
   }
+
+  override def read() {
+    // We don't expect the other side to send anything; so, we just read to detect an error or EOF.
+    try {
+      val length = channel.read(ByteBuffer.allocate(1))
+      if (length == -1) { // EOF
+        close()
+      } else if (length > 0) {
+        logWarning("Unexpected data read from SendingConnection to " + remoteConnectionManagerId)
+      }
+    } catch {
+      case e: Exception =>
+        logError("Exception while reading SendingConnection to " + remoteConnectionManagerId, e)
+        callOnExceptionCallback(e)
+        close()
+    }
+  }
 }
 
 

core/src/test/scala/spark/DistributedSuite.scala

@@ -217,6 +217,27 @@ class DistributedSuite extends FunSuite with ShouldMatchers with BeforeAndAfter
       assert(grouped.collect.size === 1)
     }
   }
+
+  test("recover from node failures with replication") {
+    import DistributedSuite.{markNodeIfIdentity, failOnMarkedIdentity}
+    DistributedSuite.amMaster = true
+    // Using more than two nodes so we don't have a symmetric communication pattern and might
+    // cache a partially correct list of peers.
+    sc = new SparkContext("local-cluster[3,1,512]", "test")
+    for (i <- 1 to 3) {
+      val data = sc.parallelize(Seq(true, false, false, false), 4)
+      data.persist(StorageLevel.MEMORY_ONLY_2)
+
+      assert(data.count === 4)
+      assert(data.map(markNodeIfIdentity).collect.size === 4)
+      assert(data.map(failOnMarkedIdentity).collect.size === 4)
+
+      // Create a new replicated RDD to make sure that cached peer information doesn't cause
+      // problems.
+      val data2 = sc.parallelize(Seq(true, true), 2).persist(StorageLevel.MEMORY_ONLY_2)
+      assert(data2.count === 2)
+    }
+  }
 }
 
 object DistributedSuite {