SPARK-1111: URL Validation Throws Error for HDFS URL's

Fixes an error where HDFS URL's cause an exception. Should be merged into master and 0.9.

Author: Patrick Wendell <pwendell@gmail.com>

Closes apache#625 from pwendell/url-validation and squashes the following commits:

d14bfe3 [Patrick Wendell] SPARK-1111: URL Validation Throws Error for HDFS URL's

(cherry picked from commit 45b15e2)
Signed-off-by: Aaron Davidson <aaron@databricks.com>

core/src/main/scala/org/apache/spark/deploy/ClientArguments.scala

@@ -17,8 +17,6 @@
 
 package org.apache.spark.deploy
 
-import java.net.URL
-
 import scala.collection.mutable.ListBuffer
 
 import org.apache.log4j.Level
@@ -71,13 +69,10 @@ private[spark] class ClientArguments(args: Array[String]) {
     case "launch" :: _master :: _jarUrl :: _mainClass :: tail =>
       cmd = "launch"
 
-      try {
-        new URL(_jarUrl)
-      } catch {
-        case e: Exception =>
-          println(s"Jar url '${_jarUrl}' is not a valid URL.")
-          println(s"Jar must be in URL format (e.g. hdfs://XX, file://XX)")
-          printUsageAndExit(-1)
+      if (!ClientArguments.isValidJarUrl(_jarUrl)) {
+        println(s"Jar url '${_jarUrl}' is not in valid format.")
+        println(s"Must be a jar file path in URL format (e.g. hdfs://XX.jar, file://XX.jar)")
+        printUsageAndExit(-1)
       }
 
       jarUrl = _jarUrl
@@ -115,3 +110,7 @@ private[spark] class ClientArguments(args: Array[String]) {
     System.exit(exitCode)
   }
 }
+
+object ClientArguments {
+  def isValidJarUrl(s: String) = s.matches("(.+):(.+)jar")
+}

core/src/test/scala/org/apache/spark/deploy/ClientSuite.scala

@@ -0,0 +1,34 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.deploy
+
+import org.scalatest.FunSuite
+import org.scalatest.matchers.ShouldMatchers
+
+class ClientSuite extends FunSuite with ShouldMatchers {
+  test("correctly validates driver jar URL's") {
+    ClientArguments.isValidJarUrl("http://someHost:8080/foo.jar") should be (true)
+    ClientArguments.isValidJarUrl("file://some/path/to/a/jarFile.jar") should be (true)
+    ClientArguments.isValidJarUrl("hdfs://someHost:1234/foo.jar") should be (true)
+
+    ClientArguments.isValidJarUrl("hdfs://someHost:1234/foo") should be (false)
+    ClientArguments.isValidJarUrl("/missing/a/protocol/jarfile.jar") should be (false)
+    ClientArguments.isValidJarUrl("not-even-a-path.jar") should be (false)
+  }
+
+}