| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.contrib.bkjournal; |
| |
| import java.io.BufferedInputStream; |
| import java.io.DataInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.Enumeration; |
| |
| import org.apache.hadoop.hdfs.server.namenode.EditLogInputStream; |
| import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp; |
| import org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader; |
| import org.apache.bookkeeper.client.LedgerHandle; |
| import org.apache.bookkeeper.client.LedgerEntry; |
| import org.apache.bookkeeper.client.BKException; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /** |
| * Input stream which reads from a BookKeeper ledger. |
| */ |
| class BookKeeperEditLogInputStream extends EditLogInputStream { |
| static final Log LOG = LogFactory.getLog(BookKeeperEditLogInputStream.class); |
| |
| private final long firstTxId; |
| private final long lastTxId; |
| private final int logVersion; |
| private final boolean inProgress; |
| private final LedgerHandle lh; |
| |
| private final FSEditLogOp.Reader reader; |
| private final FSEditLogLoader.PositionTrackingInputStream tracker; |
| |
| /** |
| * Construct BookKeeper edit log input stream. |
| * Starts reading from the first entry of the ledger. |
| */ |
| BookKeeperEditLogInputStream(final LedgerHandle lh, |
| final EditLogLedgerMetadata metadata) |
| throws IOException { |
| this(lh, metadata, 0); |
| } |
| |
| /** |
| * Construct BookKeeper edit log input stream. |
| * Starts reading from firstBookKeeperEntry. This allows the stream |
| * to take a shortcut during recovery, as it doesn't have to read |
| * every edit log transaction to find out what the last one is. |
| */ |
| BookKeeperEditLogInputStream(LedgerHandle lh, EditLogLedgerMetadata metadata, |
| long firstBookKeeperEntry) |
| throws IOException { |
| this.lh = lh; |
| this.firstTxId = metadata.getFirstTxId(); |
| this.lastTxId = metadata.getLastTxId(); |
| this.logVersion = metadata.getDataLayoutVersion(); |
| this.inProgress = metadata.isInProgress(); |
| |
| if (firstBookKeeperEntry < 0 |
| || firstBookKeeperEntry > lh.getLastAddConfirmed()) { |
| throw new IOException("Invalid first bk entry to read: " |
| + firstBookKeeperEntry + ", LAC: " + lh.getLastAddConfirmed()); |
| } |
| BufferedInputStream bin = new BufferedInputStream( |
| new LedgerInputStream(lh, firstBookKeeperEntry)); |
| tracker = new FSEditLogLoader.PositionTrackingInputStream(bin); |
| DataInputStream in = new DataInputStream(tracker); |
| |
| reader = FSEditLogOp.Reader.create(in, tracker, logVersion); |
| } |
| |
| @Override |
| public long getFirstTxId() { |
| return firstTxId; |
| } |
| |
| @Override |
| public long getLastTxId() { |
| return lastTxId; |
| } |
| |
| @Override |
| public int getVersion(boolean verifyVersion) throws IOException { |
| return logVersion; |
| } |
| |
| @Override |
| protected FSEditLogOp nextOp() throws IOException { |
| return reader.readOp(false); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| try { |
| lh.close(); |
| } catch (BKException e) { |
| throw new IOException("Exception closing ledger", e); |
| } catch (InterruptedException e) { |
| throw new IOException("Interrupted closing ledger", e); |
| } |
| } |
| |
| @Override |
| public long getPosition() { |
| return tracker.getPos(); |
| } |
| |
| @Override |
| public long length() throws IOException { |
| return lh.getLength(); |
| } |
| |
| @Override |
| public String getName() { |
| return String.format( |
| "BookKeeperLedger[ledgerId=%d,firstTxId=%d,lastTxId=%d]", lh.getId(), |
| firstTxId, lastTxId); |
| } |
| |
| @Override |
| public boolean isInProgress() { |
| return inProgress; |
| } |
| |
| /** |
| * Skip forward to specified transaction id. |
| * Currently we do this by just iterating forward. |
| * If this proves to be too expensive, this can be reimplemented |
| * with a binary search over bk entries |
| */ |
| public void skipTo(long txId) throws IOException { |
| long numToSkip = getFirstTxId() - txId; |
| |
| FSEditLogOp op = null; |
| for (long i = 0; i < numToSkip; i++) { |
| op = readOp(); |
| } |
| if (op != null && op.getTransactionId() != txId-1) { |
| throw new IOException("Corrupt stream, expected txid " |
| + (txId-1) + ", got " + op.getTransactionId()); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return ("BookKeeperEditLogInputStream {" + this.getName() + "}"); |
| } |
| |
| @Override |
| public void setMaxOpSize(int maxOpSize) { |
| reader.setMaxOpSize(maxOpSize); |
| } |
| |
| @Override |
| public boolean isLocalLog() { |
| return false; |
| } |
| |
| /** |
| * Input stream implementation which can be used by |
| * FSEditLogOp.Reader |
| */ |
| private static class LedgerInputStream extends InputStream { |
| private long readEntries; |
| private InputStream entryStream = null; |
| private final LedgerHandle lh; |
| private final long maxEntry; |
| |
| /** |
| * Construct ledger input stream |
| * @param lh the ledger handle to read from |
| * @param firstBookKeeperEntry ledger entry to start reading from |
| */ |
| LedgerInputStream(LedgerHandle lh, long firstBookKeeperEntry) |
| throws IOException { |
| this.lh = lh; |
| readEntries = firstBookKeeperEntry; |
| |
| maxEntry = lh.getLastAddConfirmed(); |
| } |
| |
| /** |
| * Get input stream representing next entry in the |
| * ledger. |
| * @return input stream, or null if no more entries |
| */ |
| private InputStream nextStream() throws IOException { |
| try { |
| if (readEntries > maxEntry) { |
| return null; |
| } |
| Enumeration<LedgerEntry> entries |
| = lh.readEntries(readEntries, readEntries); |
| readEntries++; |
| if (entries.hasMoreElements()) { |
| LedgerEntry e = entries.nextElement(); |
| assert !entries.hasMoreElements(); |
| return e.getEntryInputStream(); |
| } |
| } catch (BKException e) { |
| throw new IOException("Error reading entries from bookkeeper", e); |
| } catch (InterruptedException e) { |
| throw new IOException("Interrupted reading entries from bookkeeper", e); |
| } |
| return null; |
| } |
| |
| @Override |
| public int read() throws IOException { |
| byte[] b = new byte[1]; |
| if (read(b, 0, 1) != 1) { |
| return -1; |
| } else { |
| return b[0]; |
| } |
| } |
| |
| @Override |
| public int read(byte[] b, int off, int len) throws IOException { |
| try { |
| int read = 0; |
| if (entryStream == null) { |
| entryStream = nextStream(); |
| if (entryStream == null) { |
| return read; |
| } |
| } |
| |
| while (read < len) { |
| int thisread = entryStream.read(b, off+read, (len-read)); |
| if (thisread == -1) { |
| entryStream = nextStream(); |
| if (entryStream == null) { |
| return read; |
| } |
| } else { |
| read += thisread; |
| } |
| } |
| return read; |
| } catch (IOException e) { |
| throw e; |
| } |
| |
| } |
| } |
| } |