alluxio源碼解析-rpc調用概述-client和worker之間的block模塊的通信架構(netty版本)(3)

(1.8版本)client和worker之間的block模塊的通信架構

block做爲alluxio文件讀取或者存儲的最小基本單位,都是經過BlockOutStream和BlockInputtream實現的

其中具體的數據包傳輸有Short circuit和netty兩種實現:

• Short circuit:經過本地的ramdisk傳輸和netty傳輸
• tcp傳輸:只經過netty傳輸

輸入流代碼中,關於兩種實現的選擇邏輯:

 1 public static BlockInStream create(FileSystemContext context, BlockInfo info,
 2  WorkerNetAddress dataSource, BlockInStreamSource dataSourceType, InStreamOptions options) 3 throws IOException { 4 URIStatus status = options.getStatus(); 5 OpenFileOptions readOptions = options.getOptions(); 6 7 boolean promote = readOptions.getReadType().isPromote(); 8 9 long blockId = info.getBlockId(); 10 long blockSize = info.getLength(); 11 12 // Construct the partial read request 13 Protocol.ReadRequest.Builder builder = 14  Protocol.ReadRequest.newBuilder().setBlockId(blockId).setPromote(promote); 15 // Add UFS fallback options 16  builder.setOpenUfsBlockOptions(options.getOpenUfsBlockOptions(blockId)); 17 18 boolean shortCircuit = Configuration.getBoolean(PropertyKey.USER_SHORT_CIRCUIT_ENABLED); 19 boolean sourceSupportsDomainSocket = NettyUtils.isDomainSocketSupported(dataSource); 20 boolean sourceIsLocal = dataSourceType == BlockInStreamSource.LOCAL; 21 22 // Short circuit 23 if (sourceIsLocal && shortCircuit && !sourceSupportsDomainSocket) { 24 LOG.debug("Creating short circuit input stream for block {} @ {}", blockId, dataSource); 25 try { 26 return createLocalBlockInStream(context, dataSource, blockId, blockSize, options); 27 } catch (NotFoundException e) { 28 // Failed to do short circuit read because the block is not available in Alluxio. 29 // We will try to read via netty. So this exception is ignored. 30 LOG.warn("Failed to create short circuit input stream for block {} @ {}. Falling back to " 31 + "network transfer", blockId, dataSource); 32  } 33  } 34 35 // Netty 36 LOG.debug("Creating netty input stream for block {} @ {} from client {} reading through {}", 37  blockId, dataSource, NetworkAddressUtils.getClientHostName(), dataSource); 38 return createNettyBlockInStream(context, dataSource, dataSourceType, builder.buildPartial(), 39  blockSize, options); 40 }

輸出流代碼中,關於兩種實現的選擇邏輯:

 1 /**
 2      * @param context the file system context
 3      * @param blockId the block ID
 4      * @param blockSize the block size in bytes
 5      * @param address the Alluxio worker address
 6      * @param options the out stream options
 7      * @return the {@link PacketWriter} instance
 8      */
 9     public static PacketWriter create(FileSystemContext context, long blockId, long blockSize,
10         WorkerNetAddress address, OutStreamOptions options) throws IOException { 11 if (CommonUtils.isLocalHost(address) && Configuration 12 .getBoolean(PropertyKey.USER_SHORT_CIRCUIT_ENABLED) && !NettyUtils 13  .isDomainSocketSupported(address)) { 14 LOG.debug("Creating short circuit output stream for block {} @ {}", blockId, address); 15 return LocalFilePacketWriter.create(context, address, blockId, options); 16 } else { 17 LOG.debug("Creating netty output stream for block {} @ {} from client {}", blockId, address, 18  NetworkAddressUtils.getClientHostName()); 19 return NettyPacketWriter 20  .create(context, address, blockId, blockSize, Protocol.RequestType.ALLUXIO_BLOCK, 21  options); 22  } 23 }

 

 

short-circuit策略

針對block的的建立/摧毀,經過netty進行網絡通信

針對block的實際內容,直接經過ramdisk寫到本地,避免了使用netty進行網絡通信,

short-circuit通信-客戶端:

 

下圖是Netty版本的客戶端+LocalFileBlockWriter+LocalFileBlockReader調用過程

 

short-circuit通信-服務端:

下圖是Netty版本的服務端調用

非short-circuit

非short-circuit通信-客戶端:

下圖是Netty版本的客戶端調用過程

 

非short-circuit通信-服務端:

下圖是Netty版本的服務端調用

 

 

下一篇將介紹BlockWorker相關的功能