Example usage for org.apache.hadoop.hdfs DFSClientFaultInjector get

Introduction

In this page you can find the example usage for org.apache.hadoop.hdfs DFSClientFaultInjector get.

Prototype

public static DFSClientFaultInjector get() 

Source Link

Usage

From source file:com.mellanox.r4h.DFSInputStream.java

License:Apache License

private void actualGetFromOneDataNode(final DNAddrPair datanode, LocatedBlock block, final long start,
        final long end, byte[] buf, int offset, Map<ExtendedBlock, Set<DatanodeInfo>> corruptedBlockMap)
        throws IOException {
    DFSClientFaultInjector.get().startFetchFromDatanode();
    int refetchToken = 1; // only need to get a new access token once
    int refetchEncryptionKey = 1; // only need to get a new encryption key once

    while (true) {
        // cached block locations may have been updated by chooseDataNode()
        // or fetchBlockAt(). Always get the latest list of locations at the
        // start of the loop.
        CachingStrategy curCachingStrategy;
        boolean allowShortCircuitLocalReads;
        block = getBlockAt(block.getStartOffset());
        synchronized (infoLock) {
            curCachingStrategy = cachingStrategy;
            allowShortCircuitLocalReads = !shortCircuitForbidden();
        }/*from  w w w. j  a  v  a  2s.co  m*/
        DatanodeInfo chosenNode = datanode.info;
        InetSocketAddress targetAddr = datanode.addr;
        StorageType storageType = datanode.storageType;
        BlockReader reader = null;

        try {
            DFSClientFaultInjector.get().fetchFromDatanodeException();
            Token<BlockTokenIdentifier> blockToken = block.getBlockToken();
            int len = (int) (end - start + 1);
            reader = new BlockReaderFactory(dfsClient.getConf()).setInetSocketAddress(targetAddr)
                    .setRemotePeerFactory(dfsClient).setDatanodeInfo(chosenNode).setStorageType(storageType)
                    .setFileName(src).setBlock(block.getBlock()).setBlockToken(blockToken).setStartOffset(start)
                    .setVerifyChecksum(verifyChecksum).setClientName(dfsClient.clientName).setLength(len)
                    .setCachingStrategy(curCachingStrategy)
                    .setAllowShortCircuitLocalReads(allowShortCircuitLocalReads)
                    .setClientCacheContext(dfsClient.getClientContext()).setUserGroupInformation(dfsClient.ugi)
                    .setConfiguration(dfsClient.getConfiguration()).build();
            int nread = reader.readAll(buf, offset, len);
            updateReadStatistics(readStatistics, nread, reader);

            if (nread != len) {
                throw new IOException(
                        "truncated return from reader.read(): " + "excpected " + len + ", got " + nread);
            }
            DFSClientFaultInjector.get().readFromDatanodeDelay();
            return;
        } catch (ChecksumException e) {
            String msg = "fetchBlockByteRange(). Got a checksum exception for " + src + " at "
                    + block.getBlock() + ":" + e.getPos() + " from " + chosenNode;
            DFSClient.LOG.warn(msg);
            // we want to remember what we have tried
            addIntoCorruptedBlockMap(block.getBlock(), chosenNode, corruptedBlockMap);
            addToDeadNodes(chosenNode);
            throw new IOException(msg);
        } catch (IOException e) {
            if (e instanceof InvalidEncryptionKeyException && refetchEncryptionKey > 0) {
                DFSClient.LOG.info("Will fetch a new encryption key and retry, "
                        + "encryption key was invalid when connecting to " + targetAddr + " : " + e);
                // The encryption key used is invalid.
                refetchEncryptionKey--;
                dfsClient.clearDataEncryptionKey();
                continue;
            } else if (refetchToken > 0 && tokenRefetchNeeded(e, targetAddr)) {
                refetchToken--;
                try {
                    fetchBlockAt(block.getStartOffset());
                } catch (IOException fbae) {
                    // ignore IOE, since we can retry it later in a loop
                }
                continue;
            } else {
                String msg = "Failed to connect to " + targetAddr + " for file " + src + " for block "
                        + block.getBlock() + ":" + e;
                DFSClient.LOG.warn("Connection failure: " + msg, e);
                addToDeadNodes(chosenNode);
                throw new IOException(msg);
            }
        } finally {
            if (reader != null) {
                reader.close();
            }
        }
    }
}

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