Added options for using an external HTTP server with LocalFileShuffle

src/scala/spark/HttpServer.scala

@@ -61,18 +61,7 @@ class HttpServer(resourceBase: File) extends Logging {
     if (server == null) {
       throw new ServerStateException("Server is not started")
     } else {
-      return "http://" + getLocalIpAddress + ":" + port
+      return "http://" + Utils.localIpAddress + ":" + port
     }
   }
-
-  /**
-   * Get the local host's IP address in dotted-quad format (e.g. 1.2.3.4)
-   */
-  private def getLocalIpAddress: String = {
-    // Get local IP as an array of four bytes
-    val bytes = InetAddress.getLocalHost().getAddress()
-    // Convert the bytes to ints (keeping in mind that they may be negative)
-    // and join them into a string
-    return bytes.map(b => (b.toInt + 256) % 256).mkString(".")
-  }
 }

src/scala/spark/LocalFileShuffle.scala

@@ -97,19 +97,24 @@ object LocalFileShuffle extends Logging {
   private var nextShuffleId = new AtomicLong(0)
 
   // Variables initialized by initializeIfNeeded()
-  private var localDir: File = null
+  private var shuffleDir: File = null
   private var server: HttpServer = null
   private var serverUri: String = null
 
   private def initializeIfNeeded() = synchronized {
     if (!initialized) {
+      // TODO: localDir should be created by some mechanism common to Spark
+      // so that it can be shared among shuffle, broadcast, etc
       val localDirRoot = System.getProperty("spark.local.dir", "/tmp")
       var tries = 0
       var foundLocalDir = false
+      var localDir: File = null
+      var localDirUuid: UUID = null
       while (!foundLocalDir && tries < 10) {
         tries += 1
         try {
-          localDir = new File(localDirRoot, "spark-local-" + UUID.randomUUID())
+          localDirUuid = UUID.randomUUID()
+          localDir = new File(localDirRoot, "spark-local-" + localDirUuid)
           if (!localDir.exists()) {
             localDir.mkdirs()
             foundLocalDir = true
@@ -123,17 +128,33 @@ object LocalFileShuffle extends Logging {
         logError("Failed 10 attempts to create local dir in " + localDirRoot)
         System.exit(1)
       }
-      logInfo("Local dir: " + localDir)
+      shuffleDir = new File(localDir, "shuffle")
+      shuffleDir.mkdirs()
+      logInfo("Shuffle dir: " + shuffleDir)
+      val extServerPort = System.getProperty(
+        "spark.localFileShuffle.external.server.port", "-1").toInt
+      if (extServerPort != -1) {
+        // We're using an external HTTP server; set URI relative to its root
+        var extServerPath = System.getProperty(
+          "spark.localFileShuffle.external.server.path", "")
+        if (extServerPath != "" && !extServerPath.endsWith("/")) {
+          extServerPath += "/"
+        }
+        serverUri = "http://%s:%d/%s/spark-local-%s".format(
+          Utils.localIpAddress, extServerPort, extServerPath, localDirUuid)
+      } else {
+        // Create our own server
         server = new HttpServer(localDir)
         server.start()
         serverUri = server.uri
+      }
       initialized = true
     }
   }
 
   def getOutputFile(shuffleId: Long, inputId: Int, outputId: Int): File = {
     initializeIfNeeded()
-    val dir = new File(localDir, "shuffle/" + shuffleId + "/" + inputId)
+    val dir = new File(shuffleDir, shuffleId + "/" + inputId)
     dir.mkdirs()
     val file = new File(dir, "" + outputId)
     return file

src/scala/spark/Utils.scala

@@ -1,6 +1,7 @@
 package spark
 
 import java.io._
+import java.net.InetAddress
 import java.util.UUID
 
 import scala.collection.mutable.ArrayBuffer
@@ -112,4 +113,15 @@ object Utils {
     }
     buf
   }
+
+  /**
+   * Get the local host's IP address in dotted-quad format (e.g. 1.2.3.4)
+   */
+  def localIpAddress(): String = {
+    // Get local IP as an array of four bytes
+    val bytes = InetAddress.getLocalHost().getAddress()
+    // Convert the bytes to ints (keeping in mind that they may be negative)
+    // and join them into a string
+    return bytes.map(b => (b.toInt + 256) % 256).mkString(".")
+  }
 }