@Override
  public List<Message> peekMessagesByKey(String key) throws MessageQueueException {
    String groupRowKey = getCompositeKey(getName(), key);
    List<Message> messages = Lists.newArrayList();
    try {
      ColumnList<MessageMetadataEntry> columns =
          keyspace
              .prepareQuery(keyIndexColumnFamily)
              .getRow(groupRowKey)
              .withColumnRange(
                  metadataSerializer
                      .buildRange()
                      .greaterThanEquals((byte) MessageMetadataEntryType.MessageId.ordinal())
                      .lessThanEquals((byte) MessageMetadataEntryType.MessageId.ordinal())
                      .build())
              .execute()
              .getResult();

      for (Column<MessageMetadataEntry> entry : columns) {
        if (entry.getTtl() != 0) continue;

        Message message = peekMessage(entry.getName().getName());
        if (message != null) {
          messages.add(peekMessage(entry.getName().getName()));
        } else {
          LOG.warn("No queue item for " + entry.getName());
        }
      }
    } catch (NotFoundException e) {
    } catch (ConnectionException e) {
      throw new MessageQueueException("Error fetching row " + groupRowKey, e);
    }
    return messages;
  }
  @Override
  public Message peekMessageByKey(String key) throws MessageQueueException {
    String groupRowKey = getCompositeKey(getName(), key);
    try {
      ColumnList<MessageMetadataEntry> columns =
          keyspace
              .prepareQuery(keyIndexColumnFamily)
              .setConsistencyLevel(consistencyLevel)
              .getRow(groupRowKey)
              .withColumnRange(
                  metadataSerializer
                      .buildRange()
                      .greaterThanEquals((byte) MessageMetadataEntryType.MessageId.ordinal())
                      .lessThanEquals((byte) MessageMetadataEntryType.MessageId.ordinal())
                      .build())
              .execute()
              .getResult();

      for (Column<MessageMetadataEntry> entry : columns) {
        if (entry.getTtl() != 0) continue;
        // Return the first one we get.  Hmmm... maybe we want to do some validation checks here
        return peekMessage(entry.getName().getName());
      }
      return null;
    } catch (NotFoundException e) {
      return null;
    } catch (ConnectionException e) {
      throw new MessageQueueException("Error fetching row " + groupRowKey, e);
    }
  }
  /**
   * Read the data stored with the unique row. This data is normally a 'foreign' key to another
   * column family.
   *
   * @return
   * @throws Exception
   */
  public ByteBuffer readData() throws Exception {
    ColumnList<C> result =
        keyspace
            .prepareQuery(columnFamily)
            .setConsistencyLevel(consistencyLevel)
            .getKey(key)
            .execute()
            .getResult();

    boolean hasColumn = false;
    ByteBuffer data = null;
    for (Column<C> column : result) {
      if (column.getTtl() == 0) {
        if (hasColumn) {
          throw new IllegalStateException("Row has multiple uniquneness locks");
        }
        hasColumn = true;
        data = column.getByteBufferValue();
      }
    }

    if (!hasColumn) {
      throw new NotFoundException(this.key.toString() + " has no uniquness lock");
    }
    return data;
  }
Esempio n. 4
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  private List<MessageContext> readMessagesInternal(
      String shardName,
      int itemsToPop,
      int lockColumnCount,
      MessageQueueEntry lockColumn,
      ColumnListMutation<MessageQueueEntry> rowMutation,
      MutationBatch m,
      long curTimeMicros)
      throws BusyLockException, MessageQueueException {

    try {
      List<MessageContext> entries = Lists.newArrayList();
      RangeEndpoint re =
          ShardedDistributedMessageQueue.entrySerializer
              .makeEndpoint((byte) MessageQueueEntryType.Message.ordinal(), Equality.EQUAL)
              .append((byte) 0, Equality.EQUAL);
      if (lockColumn != null) {
        re.append(lockColumn.getTimestamp(), Equality.LESS_THAN_EQUALS);
      } else {
        re.append(TimeUUIDUtils.getMicrosTimeUUID(curTimeMicros), Equality.LESS_THAN_EQUALS);
      }

      ColumnList<MessageQueueEntry> result =
          queue
              .keyspace
              .prepareQuery(queue.queueColumnFamily)
              .setConsistencyLevel(queue.consistencyLevel)
              .getKey(shardName)
              .withColumnRange(
                  new RangeBuilder()
                      .setLimit(itemsToPop + (lockColumn == null ? 0 : (lockColumnCount + 1)))
                      .setEnd(re.toBytes())
                      .build())
              .execute()
              .getResult();
      for (Column<MessageQueueEntry> column : result) {
        if (itemsToPop == 0) {
          break;
        }
        MessageQueueEntry entry = column.getName();
        switch (entry.getType()) {
          case Lock:
            // TODO: Track number of locks read and make sure we don't exceed itemsToPop
            // We have the lock
            if (lockColumn != null && entry.getState() == MessageQueueEntryState.Acquired) {
              if (!entry.getTimestamp().equals(lockColumn.getTimestamp())) {
                throw new BusyLockException("Someone else snuck in");
              }
            }
            break;
          case Message:
            {
              try {
                itemsToPop--;
                // First, we always want to remove the old item
                String messageId = queue.getCompositeKey(shardName, entry.getMessageId());
                rowMutation.deleteColumn(entry);
                // Next, parse the message metadata and add a timeout entry
                final Message message = queue.extractMessageFromColumn(column);
                // Update the message state
                if (message != null) {
                  MessageContext context = new MessageContext();
                  context.setMessage(message);
                  // Message has a trigger so we need to figure out if it is an
                  // unfinished repeating trigger and re-add it.
                  if (message.hasTrigger()) {
                    // Read back all messageIds associated with this key and check to see if we have
                    // duplicates.
                    String groupRowKey = queue.getCompositeKey(queue.getName(), message.getKey());
                    try {
                      // Use consistency level
                      ColumnList<MessageMetadataEntry> columns =
                          queue
                              .keyspace
                              .prepareQuery(queue.keyIndexColumnFamily)
                              .getRow(groupRowKey)
                              .withColumnRange(
                                  ShardedDistributedMessageQueue.metadataSerializer
                                      .buildRange()
                                      .greaterThanEquals(
                                          (byte) MessageMetadataEntryType.MessageId.ordinal())
                                      .lessThanEquals(
                                          (byte) MessageMetadataEntryType.MessageId.ordinal())
                                      .build())
                              .execute()
                              .getResult();
                      MessageMetadataEntry mostRecentMessageMetadata = null;
                      long mostRecentTriggerTime = 0;
                      for (Column<MessageMetadataEntry> currMessageEntry : columns) {
                        MessageQueueEntry pendingMessageEntry =
                            MessageQueueEntry.fromMetadata(currMessageEntry.getName());
                        if (currMessageEntry.getTtl() == 0) {
                          long currMessageTriggerTime =
                              pendingMessageEntry.getTimestamp(TimeUnit.MICROSECONDS);
                          // First message we found, so treat as the most recent
                          if (mostRecentMessageMetadata == null) {
                            mostRecentMessageMetadata = currMessageEntry.getName();
                            mostRecentTriggerTime = currMessageTriggerTime;
                          } else {
                            // This message's trigger time is after what we thought was the most
                            // recent.
                            // Discard the previous 'most' recent and accept this one instead
                            if (currMessageTriggerTime > mostRecentTriggerTime) {
                              LOG.warn(
                                  "Need to discard : "
                                      + entry.getMessageId()
                                      + " => "
                                      + mostRecentMessageMetadata.getName());
                              m.withRow(
                                      queue.keyIndexColumnFamily,
                                      queue.getCompositeKey(queue.getName(), message.getKey()))
                                  .putEmptyColumn(
                                      mostRecentMessageMetadata, queue.metadataDeleteTTL);
                              mostRecentTriggerTime = currMessageTriggerTime;
                              mostRecentMessageMetadata = currMessageEntry.getName();
                            } else {
                              LOG.warn(
                                  "Need to discard : "
                                      + entry.getMessageId()
                                      + " => "
                                      + currMessageEntry.getName());
                              m.withRow(
                                      queue.keyIndexColumnFamily,
                                      queue.getCompositeKey(queue.getName(), message.getKey()))
                                  .putEmptyColumn(
                                      currMessageEntry.getName(), queue.metadataDeleteTTL);
                            }
                          }
                        }
                      }
                      if (mostRecentMessageMetadata != null) {
                        if (!mostRecentMessageMetadata.getName().endsWith(entry.getMessageId())) {
                          throw new DuplicateMessageException("Duplicate trigger for " + messageId);
                        }
                      }
                    } catch (NotFoundException e) {
                    } catch (ConnectionException e) {
                      throw new MessageQueueException("Error fetching row " + groupRowKey, e);
                    }
                    // Update the trigger
                    final Message nextMessage;
                    Trigger trigger = message.getTrigger().nextTrigger();
                    if (trigger != null) {
                      nextMessage = message.clone();
                      nextMessage.setTrigger(trigger);
                      context.setNextMessage(nextMessage);
                      if (message.isAutoCommitTrigger()) {
                        queue.fillMessageMutation(m, nextMessage);
                      }
                    }
                  }
                  // Message has a key so we remove this item from the messages by key index.
                  // A timeout item will be added later
                  if (message.hasKey()) {
                    m.withRow(
                            queue.keyIndexColumnFamily,
                            queue.getCompositeKey(queue.getName(), message.getKey()))
                        .putEmptyColumn(
                            MessageMetadataEntry.newMessageId(messageId), queue.metadataDeleteTTL);
                    LOG.debug(
                        "Removing from key  :  "
                            + queue.getCompositeKey(queue.getName(), message.getKey())
                            + " : "
                            + messageId);
                    if (message.isKeepHistory()) {
                      MessageHistory history = context.getHistory();
                      history.setToken(entry.getTimestamp());
                      history.setStartTime(curTimeMicros);
                      history.setTriggerTime(message.getTrigger().getTriggerTime());
                      history.setStatus(MessageStatus.RUNNING);
                      try {
                        m.withRow(queue.historyColumnFamily, message.getKey())
                            .putColumn(
                                entry.getTimestamp(),
                                queue.serializeToString(history),
                                queue.metadata.getHistoryTtl());
                      } catch (Exception e) {
                        LOG.warn("Error serializing history for key '" + message.getKey() + "'", e);
                      }
                    }
                  }
                  // Message has a timeout so we add a timeout event.
                  if (message.getTimeout() > 0) {
                    MessageQueueEntry timeoutEntry =
                        MessageQueueEntry.newMessageEntry(
                            (byte) 0,
                            TimeUUIDUtils.getMicrosTimeUUID(
                                curTimeMicros
                                    + TimeUnit.MICROSECONDS.convert(
                                        message.getTimeout(), TimeUnit.SECONDS)
                                    + (queue.counter.incrementAndGet() % 1000)),
                            MessageQueueEntryState.Busy);
                    message.setToken(timeoutEntry.getTimestamp());
                    message.setRandom(timeoutEntry.getRandom());
                    m.withRow(queue.queueColumnFamily, queue.getShardKey(message))
                        .putColumn(
                            timeoutEntry,
                            column.getStringValue(),
                            queue.metadata.getRetentionTimeout());
                    MessageMetadataEntry messageIdEntry =
                        MessageMetadataEntry.newMessageId(
                            queue.getCompositeKey(
                                queue.getShardKey(message), timeoutEntry.getMessageId()));
                    // Add the timeout column to the key
                    if (message.hasKey()) {
                      m.withRow(
                              queue.keyIndexColumnFamily,
                              queue.getCompositeKey(queue.getName(), message.getKey()))
                          .putEmptyColumn(messageIdEntry, queue.metadata.getRetentionTimeout());
                    }
                    context.setAckMessageId(messageIdEntry.getName());
                  } else {
                    message.setToken(null);
                  }
                  // Update some stats
                  switch (entry.getState()) {
                    case Waiting:
                      queue.stats.incProcessCount();
                      break;
                    case Busy:
                      queue.stats.incReprocessCount();
                      break;
                    default:
                      LOG.warn("Unknown message state: " + entry.getState());
                      // TODO:
                      break;
                  }
                  entries.add(context);
                } else {
                  queue.stats.incInvalidMessageCount();
                  // TODO: Add to poison queue
                }
              } catch (DuplicateMessageException e) {
                // OK to ignore this error.  All the proper columns will have been deleted in the
                // batch.
              }
              break;
            }
          default:
            {
              // TODO: Error: Unknown type
              break;
            }
        }
      }
      return entries;
    } catch (BusyLockException e) {
      queue.stats.incLockContentionCount();
      throw e;
    } catch (Exception e) {
      throw new MessageQueueException("Error processing queue shard : " + shardName, e);
    } finally {
      try {
        m.execute();
      } catch (Exception e) {
        throw new MessageQueueException("Error processing queue shard : " + shardName, e);
      }
    }
  }