HDFS-4525. Provide an API for knowing that whether file is closed or not. Contributed by SreeHari.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1465434 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -390,6 +390,9 @@ Release 2.0.5-beta - UNRELEASED
 
     HDFS-4618. Default transaction interval for checkpoints is too low. (todd)
 
+    HDFS-4525. Provide an API for knowing that whether file is closed or not. 
+    (SreeHari via umamahesh)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -1545,6 +1545,21 @@ public class DFSClient implements java.io.Closeable {
     }
   }
   
+  /**
+   * Close status of a file
+   * @return true if file is already closed
+   */
+  public boolean isFileClosed(String src) throws IOException{
+    checkOpen();
+    try {
+      return namenode.isFileClosed(src);
+    } catch(RemoteException re) {
+      throw re.unwrapRemoteException(AccessControlException.class,
+                                     FileNotFoundException.class,
+                                     UnresolvedPathException.class);
+    }
+  }
+  
   /**
    * Get the file info for a specific file or directory. If src
    * refers to a symlink then the FileStatus of the link is returned.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -917,4 +917,17 @@ public class DistributedFileSystem extends FileSystem {
   public boolean isInSafeMode() throws IOException {
     return setSafeMode(SafeModeAction.SAFEMODE_GET, true);
   }
+ 
+  /**
+   * Get the close status of a file
+   * @param src The path to the file
+   *
+   * @return return true if file is closed
+   * @throws FileNotFoundException if the file does not exist.
+   * @throws IOException If an I/O error occurred     
+   */
+  public boolean isFileClosed(Path src) throws IOException {
+    return dfs.isFileClosed(getPathName(src));
+  }
+  
 }

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

@@ -758,6 +758,20 @@ public interface ClientProtocol {
   public HdfsFileStatus getFileInfo(String src) throws AccessControlException,
       FileNotFoundException, UnresolvedLinkException, IOException;
   
+  /**
+   * Get the close status of a file
+   * @param src The string representation of the path to the file
+   *
+   * @return return true if file is closed
+   * @throws AccessControlException permission denied
+   * @throws FileNotFoundException file <code>src</code> is not found
+   * @throws UnresolvedLinkException if the path contains a symlink.
+   * @throws IOException If an I/O error occurred     
+   */
+  @Idempotent
+  public boolean isFileClosed(String src) throws AccessControlException,
+      FileNotFoundException, UnresolvedLinkException, IOException;
+  
   /**
    * Get the file info for a specific file or directory. If the path 
    * refers to a symlink then the FileStatus of the symlink is returned.

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

@@ -76,6 +76,8 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetPre
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetPreferredBlockSizeResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetServerDefaultsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetServerDefaultsResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.IsFileClosedRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.IsFileClosedResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MetaSaveRequestProto;
@@ -864,4 +866,17 @@ public class ClientNamenodeProtocolServerSideTranslatorPB implements
       throw new ServiceException(e);
     }
   }
+
+  @Override
+  public IsFileClosedResponseProto isFileClosed(
+      RpcController controller, IsFileClosedRequestProto request) 
+      throws ServiceException {
+    try {
+      boolean result = server.isFileClosed(request.getSrc());
+      return IsFileClosedResponseProto.newBuilder().setResult(result).build();
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+  }
+  
 }

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

@@ -77,6 +77,7 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetLis
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetListingResponseProto;
 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.IsFileClosedRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MetaSaveRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MkdirsRequestProto;
@@ -851,6 +852,19 @@ public class ClientNamenodeProtocolTranslatorPB implements
     }
   }
   
+
+  @Override
+  public boolean isFileClosed(String src) throws AccessControlException,
+      FileNotFoundException, UnresolvedLinkException, IOException {
+    IsFileClosedRequestProto req = IsFileClosedRequestProto.newBuilder()
+        .setSrc(src).build();
+    try {
+      return rpcProxy.isFileClosed(null, req).getResult();
+    } catch (ServiceException e) {
+      throw ProtobufHelper.getRemoteException(e);
+    }
+  }
+
   @Override
   public Object getUnderlyingProxyObject() {
     return rpcProxy;

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

@@ -2974,6 +2974,33 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     return stat;
   }
   
+  /**
+   * Returns true if the file is closed
+   */
+  boolean isFileClosed(String src) 
+      throws AccessControlException, UnresolvedLinkException,
+      StandbyException, IOException {
+    FSPermissionChecker pc = getPermissionChecker();	
+    checkOperation(OperationCategory.READ);
+    readLock();
+    try {
+      checkOperation(OperationCategory.READ);
+      if (isPermissionEnabled) {
+        checkTraverse(pc, src);
+      }
+      return !INodeFile.valueOf(dir.getINode(src), src).isUnderConstruction();
+    } catch (AccessControlException e) {
+      if (isAuditEnabled() && isExternalInvocation()) {
+        logAuditEvent(false, UserGroupInformation.getCurrentUser(),
+                      getRemoteIp(),
+                      "isFileClosed", src, null, null);
+      }
+      throw e;
+    } finally {
+      readUnlock();
+    }
+  }
+
   /**
    * Create all the necessary directories
    */

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

@@ -691,6 +691,11 @@ class NameNodeRpcServer implements NamenodeProtocols {
     return namesystem.getFileInfo(src, true);
   }
   
+  @Override // ClientProtocol
+  public boolean isFileClosed(String src) throws IOException{
+    return namesystem.isFileClosed(src);
+  }
+  
   @Override // ClientProtocol
   public HdfsFileStatus getFileLinkInfo(String src) throws IOException { 
     metrics.incrFileInfoOps();

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

@@ -332,6 +332,14 @@ message GetFileInfoResponseProto {
   optional HdfsFileStatusProto fs = 1;
 }
 
+message IsFileClosedRequestProto {
+  required string src = 1;
+}
+
+message IsFileClosedResponseProto {
+  required bool result = 1;
+}
+
 message GetFileLinkInfoRequestProto {
   required string src = 1;
 }
@@ -498,4 +506,6 @@ service ClientNamenodeProtocol {
       returns(SetBalancerBandwidthResponseProto);
   rpc getDataEncryptionKey(GetDataEncryptionKeyRequestProto)
       returns(GetDataEncryptionKeyResponseProto);
+  rpc isFileClosed(IsFileClosedRequestProto)
+      returns(IsFileClosedResponseProto);
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDistributedFileSystem.java

@@ -762,4 +762,27 @@ public class TestDistributedFileSystem {
       }
     }
   }
+
+  @Test(timeout=60000)
+  public void testFileCloseStatus() throws IOException {
+    Configuration conf = new HdfsConfiguration();
+    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
+    DistributedFileSystem fs = cluster.getFileSystem();
+    try {
+      // create a new file.
+      Path file = new Path("/simpleFlush.dat");
+      FSDataOutputStream output = fs.create(file);
+      // write to file
+      output.writeBytes("Some test data");
+      output.flush();
+      assertFalse("File status should be open", fs.isFileClosed(file));
+      output.close();
+      assertTrue("File status should be closed", fs.isFileClosed(file));
+    } finally {
+      if (cluster != null) {
+        cluster.shutdown();
+      }
+    }
+  }
+  
 }