HDFS-4087. Protocol changes for listSnapshots functionality. Contributed by Brandon Li.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2802@1400698 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-2802.txt

@@ -11,3 +11,6 @@ Branch-2802 Snapshot (Unreleased)
   HDFS-4083. Protocol changes for snapshots. (suresh)
 
   HDFS-4077. Add support for Snapshottable Directory. (Nicholas via suresh)
+
+  HDFS-4087. Protocol changes for listSnapshots functionality.
+  (Brandon Li via suresh)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/ClientProtocol.java

@@ -965,4 +965,12 @@ public void createSnapshot(String snapshotName, String snapshotRoot)
    */
   public void deleteSnapshot(String snapshotName, String snapshotRoot)
       throws IOException;
+
+  /**
+   * List snapshots of one directory
+   * @param snapshotRoot the path where the snapshot exists
+   */
+  public SnapshotInfo[] listSnapshots(String snapshotRoot)
+      throws IOException;
 }
+

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/SnapshotInfo.java

@@ -0,0 +1,82 @@
+/**
+ * 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 org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.FsPermissionProto;
+
+/**
+ * Interface that represents the over the wire information for a file.
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Evolving
+public class SnapshotInfo {
+  private final String snapshotName;
+  private final String snapshotRoot;
+  private final String createTime;
+  private final FsPermissionProto permission;
+  private final String owner;
+  private final String group;
+
+  public SnapshotInfo(String sname, String sroot, String ctime,
+      FsPermissionProto permission, String owner, String group) {
+    this.snapshotName = sname;
+    this.snapshotRoot = sroot;
+    this.createTime = ctime;
+    this.permission = permission;
+    this.owner = owner;
+    this.group = group;
+  }
+
+  final public String getSnapshotName() {
+    return snapshotName;
+  }
+
+  final public String getSnapshotRoot() {
+    return snapshotRoot;
+  }
+
+  final public String getCreateTime() {
+    return createTime;
+  }
+  
+  final public FsPermissionProto getPermission() {
+    return permission;
+  }
+  
+  final public String getOwner() {
+    return owner;
+  }
+  
+  final public String getGroup() {
+    return group;
+  }
+  
+  @Override
+  public String toString() {
+    return getClass().getSimpleName()
+        + "{snapshotName=" + snapshotName
+        + "; snapshotRoot=" + snapshotRoot
+        + "; createTime=" + createTime
+        + "; permission=" + permission
+        + "; owner=" + owner
+        + "; group=" + group
+        + "}";
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolServerSideTranslatorPB.java

@@ -32,6 +32,7 @@
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
+import org.apache.hadoop.hdfs.protocol.SnapshotInfo;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AbandonBlockRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AbandonBlockResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddBlockRequestProto;
@@ -135,6 +136,7 @@
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.DatanodeIDProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.DatanodeInfoProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.LocatedBlockProto;
+import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.SnapshotInfoProto;
 import org.apache.hadoop.hdfs.security.token.block.DataEncryptionKey;
 import org.apache.hadoop.io.Text;
 
@@ -881,7 +883,25 @@ public DeleteSnapshotResponseProto deleteSnapshot(RpcController controller,
   @Override
   public ListSnapshotsResponseProto listSnapshots(RpcController controller,
       ListSnapshotsRequestProto request) throws ServiceException {
-    // TODO Auto-generated method stub
+    SnapshotInfo[] result;
-    return null;
+
+    try {
+      result = server.listSnapshots(request.getSnapshotRoot());
+      ListSnapshotsResponseProto.Builder builder = ListSnapshotsResponseProto
+          .newBuilder();
+      for (SnapshotInfo si : result) {
+        SnapshotInfoProto.Builder infobuilder = SnapshotInfoProto.newBuilder();
+        infobuilder.setSnapshotName(si.getSnapshotName());
+        infobuilder.setSnapshotRoot(si.getSnapshotRoot());
+        infobuilder.setCreateTime(si.getCreateTime());
+        infobuilder.setPermission(si.getPermission());
+        infobuilder.setOwner(si.getOwner());
+        infobuilder.setGroup(si.getGroup());
+        builder.addSnapshots(infobuilder);
+      }
+      return builder.build();
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolTranslatorPB.java

@@ -42,6 +42,7 @@
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
+import org.apache.hadoop.hdfs.protocol.SnapshotInfo;
 import org.apache.hadoop.ipc.ProtocolTranslator;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
@@ -79,6 +80,8 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetPreferredBlockSizeRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetServerDefaultsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListSnapshotsRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListSnapshotsResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MetaSaveRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MkdirsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RecoverLeaseRequestProto;
@@ -101,6 +104,7 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SetTimesRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.UpdateBlockForPipelineRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.UpdatePipelineRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.SnapshotInfoProto;
 import org.apache.hadoop.hdfs.security.token.block.DataEncryptionKey;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
 import org.apache.hadoop.hdfs.server.namenode.NotReplicatedYetException;
@@ -852,6 +856,27 @@ public void deleteSnapshot(String snapshotName, String snapshotRoot)
     } catch (ServiceException e) {
       throw ProtobufHelper.getRemoteException(e);
     }
+  }
 
+  @Override
+  public SnapshotInfo[] listSnapshots(String snapshotRoot) throws IOException {
+    SnapshotInfo[] sinfo = null;
+    ListSnapshotsRequestProto req = null;
+
+    req = ListSnapshotsRequestProto.newBuilder().setSnapshotRoot(snapshotRoot)
+        .build();
+    try {
+      ListSnapshotsResponseProto resp = rpcProxy.listSnapshots(null, req);
+      sinfo = new SnapshotInfo[resp.getSnapshotsCount()];
+      for (int i = 0; i < resp.getSnapshotsCount(); i++) {
+        SnapshotInfoProto siProto = resp.getSnapshots(i);
+        sinfo[i] = new SnapshotInfo(siProto.getSnapshotName(), resp
+            .getSnapshots(i).getSnapshotRoot(), siProto.getCreateTime(),
+            siProto.getPermission(), siProto.getOwner(), siProto.getGroup());
+      }
+      return sinfo;
+    } catch (ServiceException e) {
+      throw ProtobufHelper.getRemoteException(e);
+    }
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNodeRpcServer.java

@@ -62,6 +62,7 @@
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
+import org.apache.hadoop.hdfs.protocol.SnapshotInfo;
 import org.apache.hadoop.hdfs.protocol.UnregisteredNodeException;
 import org.apache.hadoop.hdfs.protocol.UnresolvedPathException;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ClientNamenodeProtocol;
@@ -1084,4 +1085,12 @@ public void deleteSnapshot(String snapshotName, String snapshotRoot)
       throws IOException {
     // TODO Auto-generated method stub
   }
+
+  @Override
+  public SnapshotInfo[] listSnapshots(String snapshotRoot) throws IOException {
+    // TODO Auto-generated method stub  
+    SnapshotInfo[] si = new SnapshotInfo[1];
+    si[0] = new SnapshotInfo(null, null, null, null, null, null);
+    return si;
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/hdfs.proto

@@ -381,9 +381,11 @@ message VersionResponseProto {
  */
 message SnapshotInfoProto {
   required string snapshotName = 1;
-  required FsPermissionProto permission = 2;
+  required string snapshotRoot = 2;
-  required string owner = 3;
+  required FsPermissionProto permission = 3;
-  required string group = 4;
+  required string owner = 4;
+  required string group = 5;
+  required string createTime = 6;
   // TODO: do we need access time?
 }