Add CredentialsSerializer

core/src/main/scala/org/apache/spark/deploy/security/CredentialsSerializer.scala

@@ -0,0 +1,40 @@
+/*
+ * 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.security
+
+import java.io.{ByteArrayOutputStream, DataOutputStream}
+
+import org.apache.hadoop.security.Credentials
+
+class CredentialsSerializer {
+  def serialize(creds: Credentials): Array[Byte] = {
+    val byteStream = new ByteArrayOutputStream
+    val dataStream = new DataOutputStream(byteStream)
+    creds.writeTokenStorageToStream(dataStream)
+    byteStream.toByteArray
+  }
+
+  def deserialize(tokenBytes: Array[Byte]): Credentials = {
+    val tokensBuf = new java.io.ByteArrayInputStream(tokenBytes)
+
+    val creds = new Credentials()
+    creds.readTokenStorageStream(new java.io.DataInputStream(tokensBuf))
+    creds
+  }
+}
+