/// <summary>Test assumes that the file has a single block</summary>
/// <exception cref="System.IO.IOException"/>
private FilePath GetBlockForFile(Path path, bool exists)
{
LocatedBlocks blocks = nn.GetRpcServer().GetBlockLocations(path.ToString(), 0, long.MaxValue
);
NUnit.Framework.Assert.AreEqual("The test helper functions assume that each file has a single block"
, 1, blocks.GetLocatedBlocks().Count);
ExtendedBlock block = blocks.GetLocatedBlocks()[0].GetBlock();
BlockLocalPathInfo bInfo = dn0.GetFSDataset().GetBlockLocalPathInfo(block);
FilePath blockFile = new FilePath(bInfo.GetBlockPath());
NUnit.Framework.Assert.AreEqual(exists, blockFile.Exists());
return(blockFile);
}
// Multiple datanodes could be running on the local machine. Store proxies in
// a map keyed by the ipc port of the datanode.
// reader for the data file
// reader for the checksum file
/// <summary>The only way this object can be instantiated.</summary>
/// <exception cref="System.IO.IOException"/>
internal static BlockReaderLocalLegacy NewBlockReader(DFSClient.Conf conf, UserGroupInformation
userGroupInformation, Configuration configuration, string file, ExtendedBlock blk
, Org.Apache.Hadoop.Security.Token.Token <BlockTokenIdentifier> token, DatanodeInfo
node, long startOffset, long length, StorageType storageType)
{
BlockReaderLocalLegacy.LocalDatanodeInfo localDatanodeInfo = GetLocalDatanodeInfo
(node.GetIpcPort());
// check the cache first
BlockLocalPathInfo pathinfo = localDatanodeInfo.GetBlockLocalPathInfo(blk);
if (pathinfo == null)
{
if (userGroupInformation == null)
{
userGroupInformation = UserGroupInformation.GetCurrentUser();
}
pathinfo = GetBlockPathInfo(userGroupInformation, blk, node, configuration, conf.
socketTimeout, token, conf.connectToDnViaHostname, storageType);
}
// check to see if the file exists. It may so happen that the
// HDFS file has been deleted and this block-lookup is occurring
// on behalf of a new HDFS file. This time, the block file could
// be residing in a different portion of the fs.data.dir directory.
// In this case, we remove this entry from the cache. The next
// call to this method will re-populate the cache.
FileInputStream dataIn = null;
FileInputStream checksumIn = null;
BlockReaderLocalLegacy localBlockReader = null;
bool skipChecksumCheck = conf.skipShortCircuitChecksums || storageType.IsTransient
();
try
{
// get a local file system
FilePath blkfile = new FilePath(pathinfo.GetBlockPath());
dataIn = new FileInputStream(blkfile);
if (Log.IsDebugEnabled())
{
Log.Debug("New BlockReaderLocalLegacy for file " + blkfile + " of size " + blkfile
.Length() + " startOffset " + startOffset + " length " + length + " short circuit checksum "
+ !skipChecksumCheck);
}
if (!skipChecksumCheck)
{
// get the metadata file
FilePath metafile = new FilePath(pathinfo.GetMetaPath());
checksumIn = new FileInputStream(metafile);
DataChecksum checksum = BlockMetadataHeader.ReadDataChecksum(new DataInputStream(
checksumIn), blk);
long firstChunkOffset = startOffset - (startOffset % checksum.GetBytesPerChecksum
());
localBlockReader = new BlockReaderLocalLegacy(conf, file, blk, token, startOffset
, length, pathinfo, checksum, true, dataIn, firstChunkOffset, checksumIn);
}
else
{
localBlockReader = new BlockReaderLocalLegacy(conf, file, blk, token, startOffset
, length, pathinfo, dataIn);
}
}
catch (IOException e)
{
// remove from cache
localDatanodeInfo.RemoveBlockLocalPathInfo(blk);
DFSClient.Log.Warn("BlockReaderLocalLegacy: Removing " + blk + " from cache because local file "
+ pathinfo.GetBlockPath() + " could not be opened.");
throw;
}
finally
{
if (localBlockReader == null)
{
if (dataIn != null)
{
dataIn.Close();
}
if (checksumIn != null)
{
checksumIn.Close();
}
}
}
return(localBlockReader);
}