| /** |
| * 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.hadoop.hdfs.protocol; |
| |
| import java.io.IOException; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.hdfs.DFSConfigKeys; |
| import org.apache.hadoop.hdfs.security.token.block.BlockTokenIdentifier; |
| import org.apache.hadoop.hdfs.security.token.block.BlockTokenSelector; |
| import org.apache.hadoop.ipc.VersionedProtocol; |
| import org.apache.hadoop.security.KerberosInfo; |
| import org.apache.hadoop.security.token.Token; |
| import org.apache.hadoop.security.token.TokenInfo; |
| |
| /** An client-datanode protocol for block recovery |
| */ |
| @KerberosInfo( |
| serverPrincipal = DFSConfigKeys.DFS_DATANODE_USER_NAME_KEY) |
| @TokenInfo(BlockTokenSelector.class) |
| public interface ClientDatanodeProtocol extends VersionedProtocol { |
| public static final Log LOG = LogFactory.getLog(ClientDatanodeProtocol.class); |
| |
| /** |
| * 4: never return null and always return a newly generated access token |
| */ |
| public static final long versionID = 4L; |
| |
| /** Start generation-stamp recovery for specified block |
| * @param block the specified block |
| * @param keepLength keep the block length |
| * @param targets the list of possible locations of specified block |
| * @return either a new generation stamp, or the original generation stamp. |
| * Regardless of whether a new generation stamp is returned, a newly |
| * generated access token is returned as part of the return value. |
| * @throws IOException |
| */ |
| LocatedBlock recoverBlock(Block block, boolean keepLength, |
| DatanodeInfo[] targets) throws IOException; |
| |
| /** Returns a block object that contains the specified block object |
| * from the specified Datanode. |
| * @param block the specified block |
| * @return the Block object from the specified Datanode |
| * @throws IOException if the block does not exist |
| */ |
| Block getBlockInfo(Block block) throws IOException; |
| |
| /** |
| * Retrieves the path names of the block file and metadata file stored on the |
| * local file system. |
| * |
| * In order for this method to work, one of the following should be satisfied: |
| * <ul> |
| * <li> |
| * The client user must be configured at the datanode to be able to use this |
| * method.</li> |
| * <li> |
| * When security is enabled, kerberos authentication must be used to connect |
| * to the datanode.</li> |
| * </ul> |
| * |
| * @param block |
| * the specified block on the local datanode |
| * @param token |
| * the block access token. |
| * @return the BlockLocalPathInfo of a block |
| * @throws IOException |
| * on error |
| */ |
| BlockLocalPathInfo getBlockLocalPathInfo(Block block, |
| Token<BlockTokenIdentifier> token) throws IOException; |
| } |