/// <summary>
/// Server side handler of the WriteDataBlock RPC. DataNode writes block to a file and then returns success status of write.
/// </summary>
/// <param name="requestStream">Stream of bytes</param>
/// <param name="context">Context of call. Contains metadata containing blockid and list of addresses</param>
/// <returns>Status of task</returns>
public override async Task <ClientProto.StatusResponse> WriteBlock(Grpc.Core.IAsyncStreamReader <ClientProto.BlockData> requestStream, ServerCallContext context)
{
List <Metadata.Entry> metaData = context.RequestHeaders.ToList();
// Get blockID
Guid blockId = Util.GetBlockID(metaData);
int blockSize = Util.GetBlockSize(metaData);
string filePath = BlockStorage.Instance.CreateFile(blockId);
Channel channel = ConnectionManager.Instance.GetChannel(blockId);
ClientProto.StatusResponse response = new ClientProto.StatusResponse {
Type = ClientProto.StatusResponse.Types.StatusType.Success
};
// No channel found means last datanode in pipe
if (channel != null)
{
response = await WriteAndForwardBlock(requestStream, context, channel, filePath, blockId, blockSize);
}
else // Just write to file
{
response = await WriteBlock(requestStream, filePath, blockId, blockSize);
}
if (response.Type == ClientProto.StatusResponse.Types.StatusType.Success)
{
Console.WriteLine("Done writing block: " + blockId.ToString());
// Send block report to NameNode
var client = new DataNodeProto.DataNodeProto.DataNodeProtoClient(ConnectionManager.Instance.NameNodeConnection);
BlockReport.SendSingleBlockReport(client);
}
return(response);
}
/// <summary>
/// Sends block report in loop
/// </summary>
/// <param name="client">Datanode grpc client</param>
public static async Task SendBlockReport(DataNodeProto.DataNodeProto.DataNodeProtoClient client)
{
while (true)
{
SendSingleBlockReport(client);
await Task.Delay(Constants.BlockReportInterval);
}
}
/// <summary>
/// Sends a single block report
/// </summary>
/// <param name="client">Connection to NameNode</param>
public static void SendSingleBlockReport(DataNodeProto.DataNodeProto.DataNodeProtoClient client)
{
try
{
DataNodeProto.BlockReportRequest blockReport = CreateBlockReport();
DataNodeProto.StatusResponse response = client.SendBlockReport(blockReport);
}
catch (RpcException e)
{
Console.WriteLine("Blockreport failed: " + e.Message);
}
}
/// <summary>
/// Server side handler of the WriteDataBlock RPC. DataNode writes block to a file and then returns success status of write.
/// </summary>
/// <param name="requestStream">Data of block</param>
/// <param name="context">Call Context</param>
/// <returns>Status of task</returns>
public override async Task <DataNodeProto.StatusResponse> WriteDataBlock(Grpc.Core.IAsyncStreamReader <DataNodeProto.BlockData> requestStream, ServerCallContext context)
{
List <Metadata.Entry> metaData = context.RequestHeaders.ToList();
Guid blockId = Util.GetBlockID(metaData);
int blockSize = Util.GetBlockSize(metaData);
string filePath = BlockStorage.Instance.CreateFile(blockId);
bool writeSuccess = true;
try
{
// Write block to file system
using (var writerStream = new FileStream(filePath, FileMode.Append, FileAccess.Write))
{
while (await requestStream.MoveNext())
{
try
{
var bytes = requestStream.Current.Data.ToByteArray();
writerStream.Write(bytes, 0, bytes.Length);
}
catch
{
writeSuccess = false;
}
}
}
}
catch (Exception e)
{
Console.WriteLine("Writing block that was forwarded failed: " + e.Message);
}
if (BlockStorage.Instance.ValidateBlock(blockId, filePath, blockSize) && writeSuccess)
{
// Send block report to NameNode
var client = new DataNodeProto.DataNodeProto.DataNodeProtoClient(ConnectionManager.Instance.NameNodeConnection);
BlockReport.SendSingleBlockReport(client);
return(new DataNodeProto.StatusResponse {
Type = DataNodeProto.StatusResponse.Types.StatusType.Success
});
}
else
{
return(new DataNodeProto.StatusResponse {
Type = DataNodeProto.StatusResponse.Types.StatusType.Fail
});
}
}
static void Main(string[] args)
{
Console.WriteLine("Initializing DataNode");
string nameNodeIp = args[0];
int port = Convert.ToInt32(args[1]);
// Use ec2 instance manager to get the private ip address of this data node
EC2InstanceManager.InstanceManager instanceManager = EC2InstanceManager.InstanceManager.Instance;
ipAddress = instanceManager.GetPrivateIpAddress();
#if DEBUG
if (ipAddress == null)
{
ipAddress = "localhost";
}
#endif
Server server = new Server
{
Services = { DataNodeProto.DataNodeProto.BindService(new DataNodeHandler()),
ClientProto.ClientProto.BindService(new ClientHandler()) },
//Ports = { new ServerPort(ipAddress, Constants.Port, ServerCredentials.Insecure) }
Ports = { new ServerPort(ipAddress, port, ServerCredentials.Insecure) }
};
Console.WriteLine("Done initializing");
server.Start();
Console.WriteLine("Trying to connect to: " + nameNodeIp);
Channel channel = new Channel(nameNodeIp + ":" + Constants.Port, ChannelCredentials.Insecure);
ConnectionManager.Instance.NameNodeConnection = channel;
var client = new DataNodeProto.DataNodeProto.DataNodeProtoClient(channel);
// Send initial heartbeat to initialize datanode in namenode
var response = client.SendHeartBeat(HeartBeat.CreateHeartBeatRequest(), new CallOptions().WithWaitForReady(true));
Console.WriteLine("Successfully connected to namenode");
// Initialize blockstorage
BlockStorage mBlockStorage = BlockStorage.Instance;
Task heartBeatTask = HeartBeat.SendHeartBeat(client);
Task blockReportTask = BlockReport.SendBlockReport(client);
while (true)
{
}
}
/// <summary>
/// Send blockreport
/// </summary>
/// <param name="client">Datanode grpc client</param>
public static async Task SendHeartBeat(DataNodeProto.DataNodeProto.DataNodeProtoClient client)
{
while (true)
{
DataNodeProto.HeartBeatRequest heartBeatRequest = CreateHeartBeatRequest();
try
{
DataNodeProto.HeartBeatResponse response = client.SendHeartBeat(heartBeatRequest);
DataNodeProto.BlockCommand nameNodeCommands = response.Commands;
switch (nameNodeCommands.Action)
{
case DataNodeProto.BlockCommand.Types.Action.Transfer:
foreach (var block in nameNodeCommands.DataBlock.ToList())
{
// Get block data
byte[] blockData = BlockStorage.Instance.ReadBlock(Guid.Parse(block.BlockId.Value));
if (blockData != null)
{
Metadata metaData = new Metadata {
new Metadata.Entry("blockid", block.BlockId.Value),
new Metadata.Entry("blocksize", blockData.Length.ToString())
};
// Send data to each block
foreach (var dataNode in block.DataNodes)
{
Task task = ForwardBlock(dataNode, blockData, metaData);
}
}
}
break;
case DataNodeProto.BlockCommand.Types.Action.Delete:
InvalidateBlocks(nameNodeCommands.BlockList);
break;
}
}
catch (RpcException e)
{
Console.WriteLine("HeartBeat failed: " + e.Message);
}
await Task.Delay(Constants.HeartBeatInterval); // This is an HDFS default
}
}
public static async Task ForwardBlock(DataNodeProto.DataNode dataNode, byte[] blockData, Metadata metadata)
{
try
{
Console.WriteLine("Fowarding block to " + dataNode.IpAddress);
Channel channel = new Channel(dataNode.IpAddress + ":" + Constants.Port, ChannelCredentials.Insecure);
var nodeClient = new DataNodeProto.DataNodeProto.DataNodeProtoClient(channel);
using (var call = nodeClient.WriteDataBlock(metadata))
{
int remaining = blockData.Length;
while (remaining > 0)
{
var copyLength = Math.Min(Constants.StreamChunkSize, remaining);
byte[] streamBuffer = new byte[copyLength];
Buffer.BlockCopy(
blockData,
blockData.Length - remaining,
streamBuffer, 0,
copyLength);
await call.RequestStream.WriteAsync(new DataNodeProto.BlockData {
Data = Google.Protobuf.ByteString.CopyFrom(streamBuffer)
});
remaining -= copyLength;
}
await call.RequestStream.CompleteAsync();
var resp = await call.ResponseAsync;
}
}
catch (Exception e)
{
Console.WriteLine("Problem forwarding block to node," + e);
}
}