/// <exception cref="Org.Apache.Hadoop.Security.Token.SecretManager.InvalidToken"/>
private BlockReader GetBlockReaderLocal()
{
if (Log.IsTraceEnabled())
{
Log.Trace(this + ": trying to construct a BlockReaderLocal " + "for short-circuit reads."
);
}
if (pathInfo == null)
{
pathInfo = clientContext.GetDomainSocketFactory().GetPathInfo(inetSocketAddress,
conf);
}
if (!pathInfo.GetPathState().GetUsableForShortCircuit())
{
PerformanceAdvisory.Log.Debug(this + ": " + pathInfo + " is not " + "usable for short circuit; giving up on BlockReaderLocal."
);
return(null);
}
ShortCircuitCache cache = clientContext.GetShortCircuitCache();
ExtendedBlockId key = new ExtendedBlockId(block.GetBlockId(), block.GetBlockPoolId
());
ShortCircuitReplicaInfo info = cache.FetchOrCreate(key, this);
SecretManager.InvalidToken exc = info.GetInvalidTokenException();
if (exc != null)
{
if (Log.IsTraceEnabled())
{
Log.Trace(this + ": got InvalidToken exception while trying to " + "construct BlockReaderLocal via "
+ pathInfo.GetPath());
}
throw exc;
}
if (info.GetReplica() == null)
{
if (Log.IsTraceEnabled())
{
PerformanceAdvisory.Log.Debug(this + ": failed to get " + "ShortCircuitReplica. Cannot construct "
+ "BlockReaderLocal via " + pathInfo.GetPath());
}
return(null);
}
return(new BlockReaderLocal.Builder(conf).SetFilename(fileName).SetBlock(block).SetStartOffset
(startOffset).SetShortCircuitReplica(info.GetReplica()).SetVerifyChecksum(verifyChecksum
).SetCachingStrategy(cachingStrategy).SetStorageType(storageType).Build());
}
/// <summary>Fetch a pair of short-circuit block descriptors from a local DataNode.</summary>
/// <returns>
/// Null if we could not communicate with the datanode,
/// a new ShortCircuitReplicaInfo object otherwise.
/// ShortCircuitReplicaInfo objects may contain either an InvalidToken
/// exception, or a ShortCircuitReplica object ready to use.
/// </returns>
public virtual ShortCircuitReplicaInfo CreateShortCircuitReplicaInfo()
{
if (createShortCircuitReplicaInfoCallback != null)
{
ShortCircuitReplicaInfo info = createShortCircuitReplicaInfoCallback.CreateShortCircuitReplicaInfo
();
if (info != null)
{
return(info);
}
}
if (Log.IsTraceEnabled())
{
Log.Trace(this + ": trying to create ShortCircuitReplicaInfo.");
}
BlockReaderFactory.BlockReaderPeer curPeer;
while (true)
{
curPeer = NextDomainPeer();
if (curPeer == null)
{
break;
}
if (curPeer.fromCache)
{
remainingCacheTries--;
}
DomainPeer peer = (DomainPeer)curPeer.peer;
ShortCircuitShm.Slot slot = null;
ShortCircuitCache cache = clientContext.GetShortCircuitCache();
try
{
MutableBoolean usedPeer = new MutableBoolean(false);
slot = cache.AllocShmSlot(datanode, peer, usedPeer, new ExtendedBlockId(block.GetBlockId
(), block.GetBlockPoolId()), clientName);
if (usedPeer.BooleanValue())
{
if (Log.IsTraceEnabled())
{
Log.Trace(this + ": allocShmSlot used up our previous socket " + peer.GetDomainSocket
() + ". Allocating a new one...");
}
curPeer = NextDomainPeer();
if (curPeer == null)
{
break;
}
peer = (DomainPeer)curPeer.peer;
}
ShortCircuitReplicaInfo info = RequestFileDescriptors(peer, slot);
clientContext.GetPeerCache().Put(datanode, peer);
return(info);
}
catch (IOException e)
{
if (slot != null)
{
cache.FreeSlot(slot);
}
if (curPeer.fromCache)
{
// Handle an I/O error we got when using a cached socket.
// These are considered less serious, because the socket may be stale.
if (Log.IsDebugEnabled())
{
Log.Debug(this + ": closing stale domain peer " + peer, e);
}
IOUtils.Cleanup(Log, peer);
}
else
{
// Handle an I/O error we got when using a newly created socket.
// We temporarily disable the domain socket path for a few minutes in
// this case, to prevent wasting more time on it.
Log.Warn(this + ": I/O error requesting file descriptors. " + "Disabling domain socket "
+ peer.GetDomainSocket(), e);
IOUtils.Cleanup(Log, peer);
clientContext.GetDomainSocketFactory().DisableDomainSocketPath(pathInfo.GetPath()
);
return(null);
}
}
}
return(null);
}