opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/AbstractReplicatedLogImpl.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.cluster.raft;
   9
  10 import com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.Preconditions;
  12 import java.util.ArrayList;
  13 import java.util.Collections;
  14 import java.util.List;
  15 import org.slf4j.Logger;
  16 import org.slf4j.LoggerFactory;
  17
  18 /**
  19  * Abstract class handling the mapping of
  20  * logical LogEntry Index and the physical list index.
  21  */
  22 public abstract class AbstractReplicatedLogImpl implements ReplicatedLog {
  23     private static final Logger LOG = LoggerFactory.getLogger(AbstractReplicatedLogImpl.class);
  24
  25     private final String logContext;
  26
  27     // We define this as ArrayList so we can use ensureCapacity.
  28     private ArrayList<ReplicatedLogEntry> journal;
  29
  30     private long snapshotIndex = -1;
  31     private long snapshotTerm = -1;
  32
  33     // to be used for rollback during save snapshot failure
  34     private ArrayList<ReplicatedLogEntry> snapshottedJournal;
  35     private long previousSnapshotIndex = -1;
  36     private long previousSnapshotTerm = -1;
  37     private int dataSize = 0;
  38
  39     public AbstractReplicatedLogImpl(long snapshotIndex,
  40         long snapshotTerm, List<ReplicatedLogEntry> unAppliedEntries, String logContext) {
  41         this.snapshotIndex = snapshotIndex;
  42         this.snapshotTerm = snapshotTerm;
  43         this.logContext = logContext;
  44
  45         this.journal = new ArrayList<>(unAppliedEntries.size());
  46         for(ReplicatedLogEntry entry: unAppliedEntries) {
  47             append(entry);
  48         }
  49     }
  50
  51     public AbstractReplicatedLogImpl() {
  52         this(-1L, -1L, Collections.<ReplicatedLogEntry>emptyList(), "");
  53     }
  54
  55     protected int adjustedIndex(long logEntryIndex) {
  56         if (snapshotIndex < 0) {
  57             return (int) logEntryIndex;
  58         }
  59         return (int) (logEntryIndex - (snapshotIndex + 1));
  60     }
  61
  62     @Override
  63     public ReplicatedLogEntry get(long logEntryIndex) {
  64         int adjustedIndex = adjustedIndex(logEntryIndex);
  65
  66         if (adjustedIndex < 0 || adjustedIndex >= journal.size()) {
  67             // physical index should be less than list size and >= 0
  68             return null;
  69         }
  70
  71         return journal.get(adjustedIndex);
  72     }
  73
  74     @Override
  75     public ReplicatedLogEntry last() {
  76         if (journal.isEmpty()) {
  77             return null;
  78         }
  79         // get the last entry directly from the physical index
  80         return journal.get(journal.size() - 1);
  81     }
  82
  83     @Override
  84     public long lastIndex() {
  85         if (journal.isEmpty()) {
  86             // it can happen that after snapshot, all the entries of the
  87             // journal are trimmed till lastApplied, so lastIndex = snapshotIndex
  88             return snapshotIndex;
  89         }
  90         return last().getIndex();
  91     }
  92
  93     @Override
  94     public long lastTerm() {
  95         if (journal.isEmpty()) {
  96             // it can happen that after snapshot, all the entries of the
  97             // journal are trimmed till lastApplied, so lastTerm = snapshotTerm
  98             return snapshotTerm;
  99         }
 100         return last().getTerm();
 101     }
 102
 103     @Override
 104     public long removeFrom(long logEntryIndex) {
 105         int adjustedIndex = adjustedIndex(logEntryIndex);
 106         if (adjustedIndex < 0 || adjustedIndex >= journal.size()) {
 107             // physical index should be less than list size and >= 0
 108             return -1;
 109         }
 110
 111         for(int i = adjustedIndex; i < journal.size(); i++) {
 112             dataSize -= journal.get(i).size();
 113         }
 114
 115         journal.subList(adjustedIndex , journal.size()).clear();
 116
 117         return adjustedIndex;
 118     }
 119
 120     @Override
 121     public boolean append(ReplicatedLogEntry replicatedLogEntry) {
 122         if(replicatedLogEntry.getIndex() > lastIndex()) {
 123             journal.add(replicatedLogEntry);
 124             dataSize += replicatedLogEntry.size();
 125             return true;
 126         } else {
 127             LOG.warn("{}: Cannot append new entry - new index {} is not greater than the last index {}",
 128                     logContext, replicatedLogEntry.getIndex(), lastIndex(), new Exception("stack trace"));
 129             return false;
 130         }
 131     }
 132
 133     @Override
 134     public void increaseJournalLogCapacity(int amount) {
 135         journal.ensureCapacity(journal.size() + amount);
 136     }
 137
 138     @Override
 139     public List<ReplicatedLogEntry> getFrom(long logEntryIndex) {
 140         return getFrom(logEntryIndex, journal.size(), NO_MAX_SIZE);
 141     }
 142
 143     @Override
 144     public List<ReplicatedLogEntry> getFrom(long logEntryIndex, int maxEntries, long maxDataSize) {
 145         int adjustedIndex = adjustedIndex(logEntryIndex);
 146         int size = journal.size();
 147         if (adjustedIndex >= 0 && adjustedIndex < size) {
 148             // physical index should be less than list size and >= 0
 149             int maxIndex = adjustedIndex + maxEntries;
 150             if(maxIndex > size){
 151                 maxIndex = size;
 152             }
 153
 154             if(maxDataSize == NO_MAX_SIZE) {
 155                 return new ArrayList<>(journal.subList(adjustedIndex, maxIndex));
 156             } else {
 157                 List<ReplicatedLogEntry> retList = new ArrayList<>(maxIndex - adjustedIndex);
 158                 long totalSize = 0;
 159                 for(int i = adjustedIndex; i < maxIndex; i++) {
 160                     ReplicatedLogEntry entry = journal.get(i);
 161                     totalSize += entry.size();
 162                     if(totalSize <= maxDataSize) {
 163                         retList.add(entry);
 164                     } else {
 165                         if(retList.isEmpty()) {
 166                             // Edge case - the first entry's size exceeds the threshold. We need to return
 167                             // at least the first entry so add it here.
 168                             retList.add(entry);
 169                         }
 170
 171                         break;
 172                     }
 173                 }
 174
 175                 return retList;
 176             }
 177         } else {
 178             return Collections.emptyList();
 179         }
 180     }
 181
 182     @Override
 183     public long size() {
 184        return journal.size();
 185     }
 186
 187     @Override
 188     public int dataSize() {
 189         return dataSize;
 190     }
 191
 192     @Override
 193     public boolean isPresent(long logEntryIndex) {
 194         if (logEntryIndex > lastIndex()) {
 195             // if the request logical index is less than the last present in the list
 196             return false;
 197         }
 198         int adjustedIndex = adjustedIndex(logEntryIndex);
 199         return (adjustedIndex >= 0);
 200     }
 201
 202     @Override
 203     public boolean isInSnapshot(long logEntryIndex) {
 204         return logEntryIndex <= snapshotIndex && snapshotIndex != -1;
 205     }
 206
 207     @Override
 208     public long getSnapshotIndex() {
 209         return snapshotIndex;
 210     }
 211
 212     @Override
 213     public long getSnapshotTerm() {
 214         return snapshotTerm;
 215     }
 216
 217     @Override
 218     public void setSnapshotIndex(long snapshotIndex) {
 219         this.snapshotIndex = snapshotIndex;
 220     }
 221
 222     @Override
 223     public void setSnapshotTerm(long snapshotTerm) {
 224         this.snapshotTerm = snapshotTerm;
 225     }
 226
 227     @Override
 228     public void clear(int startIndex, int endIndex) {
 229         journal.subList(startIndex, endIndex).clear();
 230     }
 231
 232     @Override
 233     public void snapshotPreCommit(long snapshotCapturedIndex, long snapshotCapturedTerm) {
 234         Preconditions.checkArgument(snapshotCapturedIndex >= snapshotIndex,
 235                 "snapshotCapturedIndex must be greater than or equal to snapshotIndex");
 236
 237         snapshottedJournal = new ArrayList<>(journal.size());
 238
 239         List<ReplicatedLogEntry> snapshotJournalEntries = journal.subList(0, (int) (snapshotCapturedIndex - snapshotIndex));
 240
 241         snapshottedJournal.addAll(snapshotJournalEntries);
 242         snapshotJournalEntries.clear();
 243
 244         previousSnapshotIndex = snapshotIndex;
 245         setSnapshotIndex(snapshotCapturedIndex);
 246
 247         previousSnapshotTerm = snapshotTerm;
 248         setSnapshotTerm(snapshotCapturedTerm);
 249     }
 250
 251     @Override
 252     public void snapshotCommit() {
 253         snapshottedJournal = null;
 254         previousSnapshotIndex = -1;
 255         previousSnapshotTerm = -1;
 256         dataSize = 0;
 257         // need to recalc the datasize based on the entries left after precommit.
 258         for(ReplicatedLogEntry logEntry : journal) {
 259             dataSize += logEntry.size();
 260         }
 261
 262     }
 263
 264     @Override
 265     public void snapshotRollback() {
 266         snapshottedJournal.addAll(journal);
 267         journal = snapshottedJournal;
 268         snapshottedJournal = null;
 269
 270         snapshotIndex = previousSnapshotIndex;
 271         previousSnapshotIndex = -1;
 272
 273         snapshotTerm = previousSnapshotTerm;
 274         previousSnapshotTerm = -1;
 275     }
 276
 277     @VisibleForTesting
 278     ReplicatedLogEntry getAtPhysicalIndex(int index) {
 279         return journal.get(index);
 280     }
 281 }