String fillMessageMutation(MutationBatch mb, Message message) throws MessageQueueException {
// Get the execution time from the message or set to current time so it runs immediately
long curTimeMicros;
if (!message.hasTrigger()) {
curTimeMicros =
TimeUnit.MICROSECONDS.convert(System.currentTimeMillis(), TimeUnit.MILLISECONDS);
} else {
curTimeMicros =
TimeUnit.MICROSECONDS.convert(
message.getTrigger().getTriggerTime(), TimeUnit.MILLISECONDS);
}
curTimeMicros += (counter.incrementAndGet() % 1000);
// Update the message for the new token
message.setToken(TimeUUIDUtils.getMicrosTimeUUID(curTimeMicros));
// Set up the queue entry
MessageQueueEntry entry =
MessageQueueEntry.newMessageEntry(
message.getPriority(), message.getToken(), MessageQueueEntryState.Waiting);
// Convert the message object to JSON
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
mapper.writeValue(baos, message);
baos.flush();
} catch (Exception e) {
throw new MessageQueueException("Failed to serialize message data: " + message, e);
}
// Write the queue entry
String shardKey = getShardKey(message);
mb.withRow(queueColumnFamily, shardKey)
.putColumn(entry, new String(baos.toByteArray()), metadata.getRetentionTimeout());
// Write the lookup from queue key to queue entry
if (message.hasKey()) {
mb.withRow(keyIndexColumnFamily, getCompositeKey(getName(), message.getKey()))
.putEmptyColumn(
MessageMetadataEntry.newMessageId(getCompositeKey(shardKey, entry.getMessageId())),
metadata.getRetentionTimeout());
}
// Allow hook processing
for (MessageQueueHooks hook : hooks) {
hook.beforeSendMessage(message, mb);
}
// Update state and retun the token
stats.incSendMessageCount();
return getCompositeKey(shardKey, entry.getMessageId());
}
public long[] fire() {
final Callable<Long> task =
new Callable<Long>() {
@Override
public Long call() throws Exception {
return System.nanoTime();
}
};
final long[] start = new long[numProbes];
final Future<Long>[] futs = new Future[numProbes];
for (int i = 0; i < numProbes; i++) {
start[i] = System.nanoTime();
futs[i] = executor.submit(task);
}
final long[] res = new long[numProbes];
Arrays.fill(res, -1);
try {
for (int i = 0; i < numProbes; i++) {
final long nanos = futs[i].get() - start[i];
res[i] = TimeUnit.MICROSECONDS.convert(nanos, TimeUnit.NANOSECONDS);
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
} catch (ExecutionException e) {
throw new AssertionError(e);
}
return res;
}
public String printAvg(String unitName, double cnt) {
endNs = System.nanoTime();
long elapsedNs = endNs - startNs;
long avgNs = _avg(elapsedNs, cnt);
return String.format(
"Completed %s %s in %s ms. AvgPer: %s ms/%s \u00b5s/%s ns.",
cnt,
unitName,
TimeUnit.MILLISECONDS.convert(elapsedNs, TimeUnit.NANOSECONDS),
TimeUnit.MILLISECONDS.convert(avgNs, TimeUnit.NANOSECONDS),
TimeUnit.MICROSECONDS.convert(avgNs, TimeUnit.NANOSECONDS),
avgNs);
}
private void fillAckMutation(MessageContext context, MutationBatch mb) {
queue.stats.incAckMessageCount();
Message message = context.getMessage();
// Token refers to the timeout event. If 0 (i.e. no) timeout was specified
// then the token will not exist
if (message.getToken() != null) {
MessageQueueEntry entry = MessageQueueEntry.newBusyEntry(message);
// Remove timeout entry from the queue
mb.withRow(queue.queueColumnFamily, queue.getShardKey(message)).deleteColumn(entry);
// Remove entry lookup from the key, if one exists
if (message.hasKey()) {
mb.withRow(
queue.keyIndexColumnFamily,
queue.getCompositeKey(queue.getName(), message.getKey()))
.putEmptyColumn(
MessageMetadataEntry.newMessageId(
queue.getCompositeKey(queue.getShardKey(message), entry.getMessageId())),
queue.metadataDeleteTTL);
if (message.isKeepHistory()) {
MessageHistory history = context.getHistory();
if (history.getStatus() == MessageStatus.RUNNING) {
history.setStatus(MessageStatus.DONE);
}
history.setEndTime(
TimeUnit.MICROSECONDS.convert(System.currentTimeMillis(), TimeUnit.MILLISECONDS));
try {
mb.withRow(queue.historyColumnFamily, message.getKey())
.putColumn(
history.getToken(),
queue.serializeToString(context.getHistory()),
queue.metadata.getHistoryTtl()); // TTL
} catch (Exception e) {
LOG.warn("Error serializing message history for " + message.getKey(), e);
}
}
}
// Run hooks
for (MessageQueueHooks hook : queue.hooks) {
hook.beforeAckMessage(message, mb);
}
}
if (context.getNextMessage() != null) {
try {
queue.fillMessageMutation(mb, context.getNextMessage());
} catch (MessageQueueException e) {
LOG.warn("Error filling nextMessage for " + message.getKey(), e);
}
}
}
protected Map<String, Object> buildTimerMap(Timer t) {
Map<String, Object> metrics = Maps.newHashMap();
if (t == null) {
return metrics;
}
TimeUnit timeUnit = TimeUnit.MICROSECONDS;
Map<String, Object> time = Maps.newHashMap();
time.put("max", TimeUnit.MICROSECONDS.convert(t.getSnapshot().getMax(), TimeUnit.NANOSECONDS));
time.put("min", TimeUnit.MICROSECONDS.convert(t.getSnapshot().getMin(), TimeUnit.NANOSECONDS));
time.put(
"mean",
TimeUnit.MICROSECONDS.convert((long) t.getSnapshot().getMean(), TimeUnit.NANOSECONDS));
time.put(
"95th_percentile",
TimeUnit.MICROSECONDS.convert(
(long) t.getSnapshot().get95thPercentile(), TimeUnit.NANOSECONDS));
time.put(
"98th_percentile",
TimeUnit.MICROSECONDS.convert(
(long) t.getSnapshot().get98thPercentile(), TimeUnit.NANOSECONDS));
time.put(
"99th_percentile",
TimeUnit.MICROSECONDS.convert(
(long) t.getSnapshot().get99thPercentile(), TimeUnit.NANOSECONDS));
time.put(
"std_dev",
TimeUnit.MICROSECONDS.convert((long) t.getSnapshot().getStdDev(), TimeUnit.NANOSECONDS));
Map<String, Object> rate = Maps.newHashMap();
rate.put("one_minute", t.getOneMinuteRate());
rate.put("five_minute", t.getFiveMinuteRate());
rate.put("fifteen_minute", t.getFifteenMinuteRate());
rate.put("total", t.getCount());
rate.put("mean", t.getMeanRate());
metrics.put("rate_unit", "events/second");
metrics.put("duration_unit", timeUnit.toString().toLowerCase());
metrics.put("time", time);
metrics.put("rate", rate);
return metrics;
}
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);
}
}
}
public Builder withLockTimeout(Long timeout, TimeUnit units) {
this.lockTimeout = TimeUnit.MICROSECONDS.convert(timeout, units);
return this;
}
public Builder withTimeBuckets(int bucketCount, int bucketDuration, TimeUnit units) {
this.metadata.setPartitionDuration(TimeUnit.MICROSECONDS.convert(bucketDuration, units));
this.metadata.setPartitionCount(bucketCount);
return this;
}
/**
* ShardedDistributedMessageQueue is a Cassandra backed client driven message queue.
*
* <p>Key features 1. Time partition circular row key set used to time bound how much a wide row can
* grow. This, along with an aggressive gc_grace_seconds will give cassandra a chance to clear out
* the row before the clients cycle back to the time partition. Only one partition is active at any
* given time. 2. Mod sharding per partition based on message time. This solves the problem of lock
* contention on the acitve time partition. 3. Smart processing of partitions and shards to read
* mostly from the current time shard but allowing some cycle for processing older shards 4.
* Read-ack model of removing elements from the queue. As part of removing an element from the queue
* the client inserts a timeout message. Once the message has been processed the timeout message is
* removed from the queue. Otherwise it will be processed if it's time arrived and it is still in
* the queue. 5. Batch read of events 6. Batch insert of events
*
* <p>Algorithm:
*
* <p>Messages are stored as columns in an index where the columns are stored in time order. The
* time can be the current time for immediate execution or future time for recurring or scheduled
* messages. Jobs will be processed in time order.
*
* <p>To achieve higher scalability the job queue (implemented as a row) is sharded by a user
* provided shard. Rows also implement a rolling time window which is used to alleviate tombstone
* pressure
*
* <p>Enque:
*
* <p>Deque: 1. Lock + read top N columns 2. Select M jobs to process Select jobs in <state> =
* scheduled If any jobs are marked as processing then delete and update their state 3. Release the
* lock with a mutation that has a delete for the columns being processed and insert with the same
* data but <state> = processing 4. Process the jobs 5. If the processing thread is about to enter a
* section which is not repeatable then update the column by changing the state to NotRepeatable. 6.
* Issue a delete for processed job
*
* <p>Schema: RowKey: TimeBucket + Shard Column: <type><priority><timeuuid><state> Value: Job Data
*
* <p><type> 0 - Lock meta 1 - Queue item <state> 0 - Lock columns - There are special columns that
* are used to lock the row 1 - Scheduled 2 - Processing - timeuuid = timeout 3 - NotRepeatable -
* special indicator that tells the queue that the job is not replayble since there could be a
* persistence
*
* <p>Recurring Messages:
*
* <p>Column families: Queue KeyLookup History
*
* @author elandau
*/
public class ShardedDistributedMessageQueue implements MessageQueue {
private static final Logger LOG = LoggerFactory.getLogger(ShardedDistributedMessageQueue.class);
public static final char COMPOSITE_ID_DELIMITER = ':';
public static final char COMPOSITE_KEY_DELIMITER = '$';
public static final String DEFAULT_COLUMN_FAMILY_NAME = "Queues";
public static final ConsistencyLevel DEFAULT_CONSISTENCY_LEVEL = ConsistencyLevel.CL_LOCAL_QUORUM;
public static final RetryPolicy DEFAULT_RETRY_POLICY = RunOnce.get();
public static final long DEFAULT_LOCK_TIMEOUT =
TimeUnit.MICROSECONDS.convert(30, TimeUnit.SECONDS);
public static final Integer DEFAULT_LOCK_TTL =
(int) TimeUnit.SECONDS.convert(2, TimeUnit.MINUTES);
public static final Integer DEFAULT_METADATA_DELETE_TTL =
(int) TimeUnit.SECONDS.convert(2, TimeUnit.SECONDS);
public static final Boolean DEFAULT_POISON_QUEUE_ENABLED = false;
public static final String DEFAULT_QUEUE_SUFFIX = "_queue";
public static final String DEFAULT_METADATA_SUFFIX = "_metadata";
public static final String DEFAULT_HISTORY_SUFFIX = "_history";
public static final long SCHEMA_CHANGE_DELAY = 3000;
public static final ImmutableMap<String, Object> DEFAULT_COLUMN_FAMILY_SETTINGS =
ImmutableMap.<String, Object>builder()
.put("read_repair_chance", 1.0)
.put("gc_grace_seconds", 5) // TODO: Calculate gc_grace_seconds
.put("compaction_strategy", "SizeTieredCompactionStrategy")
.build();
static final AnnotatedCompositeSerializer<MessageQueueEntry> entrySerializer =
new AnnotatedCompositeSerializer<MessageQueueEntry>(MessageQueueEntry.class);
static final AnnotatedCompositeSerializer<MessageMetadataEntry> metadataSerializer =
new AnnotatedCompositeSerializer<MessageMetadataEntry>(MessageMetadataEntry.class);
static final ObjectMapper mapper = new ObjectMapper();
{
mapper.getSerializationConfig().setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);
mapper.enableDefaultTyping();
}
/** @author elandau */
public static class Builder {
private String columnFamilyName = DEFAULT_COLUMN_FAMILY_NAME;
private ShardLockManager lockManager;
private Keyspace keyspace;
private ConsistencyLevel consistencyLevel = DEFAULT_CONSISTENCY_LEVEL;
private long lockTimeout = DEFAULT_LOCK_TIMEOUT;
private int lockTtl = DEFAULT_LOCK_TTL;
private String queueName = MessageQueueMetadata.DEFAULT_QUEUE_NAME;
private int metadataDeleteTTL = DEFAULT_METADATA_DELETE_TTL;
private Collection<MessageQueueHooks> hooks = Lists.newArrayList();
private MessageQueueMetadata metadata = new MessageQueueMetadata();
private MessageQueueStats stats;
private Boolean bPoisonQueueEnabled = DEFAULT_POISON_QUEUE_ENABLED;
private Map<String, Object> columnFamilySettings = DEFAULT_COLUMN_FAMILY_SETTINGS;
private ShardReaderPolicy.Factory shardReaderPolicyFactory;
private ModShardPolicy modShardPolicy;
public Builder() {
metadata.setQueueName(queueName);
}
public Builder withColumnFamily(String columnFamilyName) {
this.columnFamilyName = columnFamilyName;
return this;
}
public Builder withMetadata(MessageQueueMetadata metadata) {
this.metadata = metadata;
return this;
}
public Builder withShardCount(int count) {
this.metadata.setShardCount(count);
return this;
}
public Builder withTimeBuckets(int bucketCount, int bucketDuration, TimeUnit units) {
this.metadata.setPartitionDuration(TimeUnit.MICROSECONDS.convert(bucketDuration, units));
this.metadata.setPartitionCount(bucketCount);
return this;
}
/** @deprecated Use withTimeBuckets instead */
public Builder withBuckets(int bucketCount, int bucketDuration, TimeUnit units) {
return withTimeBuckets(bucketCount, bucketDuration, units);
}
public Builder withRetentionTimeout(Long timeout, TimeUnit units) {
this.metadata.setRetentionTimeout(timeout, units);
return this;
}
public Builder withLockTimeout(Long timeout, TimeUnit units) {
this.lockTimeout = TimeUnit.MICROSECONDS.convert(timeout, units);
return this;
}
public Builder withLockTtl(Long ttl, TimeUnit units) {
this.lockTtl = (int) TimeUnit.SECONDS.convert(ttl, units);
return this;
}
/**
* Define this on the ShardReaderPolicy instead
*
* @param internval
* @param units
* @return
*/
@Deprecated
public Builder withPollInterval(Long internval, TimeUnit units) {
this.metadata.setPollInterval(TimeUnit.MILLISECONDS.convert(internval, units));
return this;
}
public Builder withQueueName(String queueName) {
this.metadata.setQueueName(queueName);
return this;
}
public Builder withConsistencyLevel(ConsistencyLevel level) {
this.consistencyLevel = level;
return this;
}
public Builder withColumnFamilySettings(Map<String, Object> settings) {
this.columnFamilySettings = settings;
return this;
}
public Builder withKeyspace(Keyspace keyspace) {
this.keyspace = keyspace;
return this;
}
public Builder withStats(MessageQueueStats stats) {
this.stats = stats;
return this;
}
public Builder withHook(MessageQueueHooks hooks) {
this.hooks.add(hooks);
return this;
}
public Builder withHooks(Collection<MessageQueueHooks> hooks) {
this.hooks.addAll(hooks);
return this;
}
public Builder withPoisonQueue(Boolean enabled) {
this.bPoisonQueueEnabled = enabled;
return this;
}
public Builder withModShardPolicy(ModShardPolicy policy) {
this.modShardPolicy = policy;
return this;
}
public Builder withShardReaderPolicy(final ShardReaderPolicy shardReaderPolicy) {
this.shardReaderPolicyFactory =
new ShardReaderPolicy.Factory() {
@Override
public ShardReaderPolicy create(MessageQueueMetadata metadata) {
return shardReaderPolicy;
}
};
return this;
}
public Builder withShardReaderPolicy(ShardReaderPolicy.Factory shardReaderPolicyFactory) {
this.shardReaderPolicyFactory = shardReaderPolicyFactory;
return this;
}
public Builder withShardLockManager(ShardLockManager mgr) {
this.lockManager = mgr;
return this;
}
public ShardedDistributedMessageQueue build() throws MessageQueueException {
Preconditions.checkArgument(
TimeUnit.SECONDS.convert(lockTimeout, TimeUnit.MICROSECONDS) < lockTtl,
"Timeout "
+ lockTtl
+ " seconds must be less than TTL "
+ TimeUnit.SECONDS.convert(lockTtl, TimeUnit.MICROSECONDS)
+ " seconds");
Preconditions.checkNotNull(keyspace, "Must specify keyspace");
if (shardReaderPolicyFactory == null)
shardReaderPolicyFactory = TimePartitionedShardReaderPolicy.Factory.builder().build();
if (modShardPolicy == null) modShardPolicy = TimeModShardPolicy.getInstance();
if (stats == null) stats = new CountingQueueStats();
return new ShardedDistributedMessageQueue(this);
}
}
// Immutable after configuration
final ShardLockManager lockManager;
final ColumnFamily<String, MessageQueueEntry> queueColumnFamily;
final ColumnFamily<String, MessageMetadataEntry> keyIndexColumnFamily;
final ColumnFamily<String, UUID> historyColumnFamily;
final Keyspace keyspace;
final ConsistencyLevel consistencyLevel;
final long lockTimeout;
final int lockTtl;
final int metadataDeleteTTL;
final Collection<MessageQueueHooks> hooks;
final MessageQueueMetadata metadata;
final Boolean bPoisonQueueEnabled;
final Map<String, Object> columnFamilySettings;
final ShardReaderPolicy shardReaderPolicy;
final ModShardPolicy modShardPolicy;
final Function<String, Message> invalidMessageHandler =
new Function<String, Message>() {
@Override
public Message apply(String input) {
LOG.warn("Invalid message: " + input);
return null;
}
};
final MessageQueueStats stats;
final AtomicLong counter = new AtomicLong(new Random().nextInt(1000));
private ShardedDistributedMessageQueue(Builder builder) throws MessageQueueException {
this.queueColumnFamily =
ColumnFamily.newColumnFamily(
builder.columnFamilyName + DEFAULT_QUEUE_SUFFIX,
StringSerializer.get(),
entrySerializer);
this.keyIndexColumnFamily =
ColumnFamily.newColumnFamily(
builder.columnFamilyName + DEFAULT_METADATA_SUFFIX,
StringSerializer.get(),
metadataSerializer);
this.historyColumnFamily =
ColumnFamily.newColumnFamily(
builder.columnFamilyName + DEFAULT_HISTORY_SUFFIX,
StringSerializer.get(),
TimeUUIDSerializer.get());
this.consistencyLevel = builder.consistencyLevel;
this.keyspace = builder.keyspace;
this.hooks = builder.hooks;
this.modShardPolicy = builder.modShardPolicy;
this.lockManager = builder.lockManager;
this.lockTimeout = builder.lockTimeout;
this.lockTtl = builder.lockTtl;
this.bPoisonQueueEnabled = builder.bPoisonQueueEnabled;
this.metadata = builder.metadata;
this.columnFamilySettings = builder.columnFamilySettings;
this.metadataDeleteTTL = builder.metadataDeleteTTL;
this.stats = builder.stats;
this.shardReaderPolicy = builder.shardReaderPolicyFactory.create(metadata);
// try {
// Column<MessageQueueEntry> column = keyspace.prepareQuery(queueColumnFamily)
// .setConsistencyLevel(consistencyLevel)
// .getRow(getName())
// .getColumn(MessageQueueEntry.newMetadataEntry())
// .execute()
// .getResult();
//
// ByteArrayInputStream bais = new ByteArrayInputStream(column.getByteArrayValue());
// MessageQueueSettings existingSettings = mapper.readValue(bais,
// MessageQueueSettings.class);
//
// // TODO: Override some internal settings with those persisted in the queue
// metadata
// }
// catch (NotFoundException e) {
// LOG.info("Message queue metadata not found. Queue does not exist in CF and will
// be created now.");
// }
// catch (BadRequestException e) {
// if (e.isUnconfiguredColumnFamilyError()) {
// LOG.info("Column family does not exist. Call createStorage() to create column
// family.");
// }
// else {
// throw new MessageQueueException("Error getting message queue metadata", e);
// }
// }
// catch (Exception e) {
// throw new MessageQueueException("Error getting message queue metadata", e);
// }
}
/**
* Return the shard for this message
*
* @param message
* @return
*/
String getShardKey(Message message) {
return getShardKey(
message.getTokenTime(), this.modShardPolicy.getMessageShard(message, metadata));
}
/**
* Return the shard for this timestamp
*
* @param message
* @return
*/
private String getShardKey(long messageTime, int modShard) {
long timePartition;
if (metadata.getPartitionDuration() != null)
timePartition =
(messageTime / metadata.getPartitionDuration()) % metadata.getPartitionCount();
else timePartition = 0;
return getName() + ":" + timePartition + ":" + modShard;
}
String getCompositeKey(String name, String key) {
return name + COMPOSITE_KEY_DELIMITER + key;
}
private static String[] splitCompositeKey(String key) throws MessageQueueException {
String[] parts = StringUtils.split(key, COMPOSITE_KEY_DELIMITER);
if (parts.length != 2) {
throw new MessageQueueException(
"Invalid key '" + key + "'. Expected format <queue|shard>$<name>. ");
}
return parts;
}
<T> String serializeToString(T trigger)
throws JsonGenerationException, JsonMappingException, IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
mapper.writeValue(baos, trigger);
baos.flush();
return baos.toString();
}
private <T> T deserializeString(String data, Class<T> clazz)
throws JsonParseException, JsonMappingException, IOException {
return (T) mapper.readValue(new ByteArrayInputStream(data.getBytes()), clazz);
}
@SuppressWarnings({"unused", "unchecked"})
private <T> T deserializeString(String data, String className)
throws JsonParseException, JsonMappingException, IOException, ClassNotFoundException {
return (T)
mapper.readValue(new ByteArrayInputStream(data.getBytes()), Class.forName(className));
}
@Override
public String getName() {
return metadata.getQueueName();
}
@Override
public long getMessageCount() throws MessageQueueException {
Map<String, Integer> counts = getShardCounts();
long count = 0;
for (Integer value : counts.values()) {
count += value;
}
return count;
}
@Override
public Map<String, Integer> getShardCounts() throws MessageQueueException {
try {
List<String> keys = Lists.newArrayList();
for (int i = 0; i < metadata.getPartitionCount(); i++) {
for (int j = 0; j < metadata.getShardCount(); j++) {
keys.add(getName() + ":" + i + ":" + j);
}
}
Map<String, Integer> result = Maps.newTreeMap();
result.putAll(
keyspace
.prepareQuery(queueColumnFamily)
.getKeySlice(keys)
.getColumnCounts()
.execute()
.getResult());
return result;
} catch (ConnectionException e) {
throw new MessageQueueException("Failed to get counts", e);
}
}
@Override
public void clearMessages() throws MessageQueueException {
LOG.info("Clearing messages from '" + getName() + "'");
MutationBatch mb = keyspace.prepareMutationBatch().setConsistencyLevel(consistencyLevel);
for (MessageQueueShard partition : shardReaderPolicy.listShards()) {
mb.withRow(queueColumnFamily, partition.getName()).delete();
}
try {
mb.execute();
} catch (ConnectionException e) {
throw new MessageQueueException("Failed to clear messages from queue " + getName(), e);
}
}
@Override
public void deleteQueue() throws MessageQueueException {
LOG.info("Deleting queue '" + getName() + "'");
MutationBatch mb = keyspace.prepareMutationBatch().setConsistencyLevel(consistencyLevel);
for (MessageQueueShard partition : shardReaderPolicy.listShards()) {
mb.withRow(queueColumnFamily, partition.getName()).delete();
}
mb.withRow(queueColumnFamily, getName());
try {
mb.execute();
} catch (ConnectionException e) {
throw new MessageQueueException("Failed to clear messages from queue " + getName(), e);
}
}
@Override
public Message peekMessage(String messageId) throws MessageQueueException {
String[] parts = splitCompositeKey(messageId);
String shardKey = parts[0];
MessageQueueEntry entry = new MessageQueueEntry(parts[1]);
try {
Column<MessageQueueEntry> column =
keyspace
.prepareQuery(queueColumnFamily)
.setConsistencyLevel(consistencyLevel)
.getKey(shardKey)
.getColumn(entry)
.execute()
.getResult();
try {
ByteArrayInputStream bais = new ByteArrayInputStream(column.getByteArrayValue());
return mapper.readValue(bais, Message.class);
} catch (Exception e) {
LOG.warn("Error parsing message", e);
// Error parsing the message so we pass it on to the invalid message handler.
try {
return invalidMessageHandler.apply(column.getStringValue());
} catch (Exception e2) {
LOG.warn("Error handling invalid message message", e2);
throw new MessageQueueException("Error parsing message " + messageId);
}
}
} catch (NotFoundException e) {
return null;
} catch (ConnectionException e) {
throw new MessageQueueException("Error getting message " + messageId, e);
}
}
@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);
}
}
@Override
public boolean deleteMessageByKey(String key) throws MessageQueueException {
MutationBatch mb = keyspace.prepareMutationBatch().setConsistencyLevel(consistencyLevel);
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) {
String[] parts = splitCompositeKey(entry.getName().getName());
String shardKey = parts[0];
MessageQueueEntry queueEntry = new MessageQueueEntry(parts[1]);
mb.withRow(queueColumnFamily, shardKey).deleteColumn(queueEntry);
}
mb.withRow(keyIndexColumnFamily, groupRowKey).delete();
} catch (NotFoundException e) {
return false;
} catch (ConnectionException e) {
throw new MessageQueueException("Error fetching row " + groupRowKey, e);
}
try {
mb.execute();
} catch (ConnectionException e) {
throw new MessageQueueException("Error deleting queue item " + groupRowKey, e);
}
return true;
}
@Override
public void deleteMessage(String messageId) throws MessageQueueException {
String[] parts = splitCompositeKey(messageId);
String shardKey = parts[0];
MessageQueueEntry entry = new MessageQueueEntry(parts[1]);
try {
keyspace
.prepareColumnMutation(queueColumnFamily, shardKey, entry)
.setConsistencyLevel(consistencyLevel)
.deleteColumn()
.execute();
} catch (ConnectionException e) {
throw new MessageQueueException("Error deleting message " + messageId, e);
}
}
@Override
public void deleteMessages(Collection<String> messageIds) throws MessageQueueException {
MutationBatch mb = keyspace.prepareMutationBatch().setConsistencyLevel(consistencyLevel);
for (String messageId : messageIds) {
String[] parts = splitCompositeKey(messageId);
String shardKey = parts[0];
MessageQueueEntry entry = new MessageQueueEntry(parts[1]);
mb.withRow(queueColumnFamily, shardKey).deleteColumn(entry);
}
try {
mb.execute();
} catch (ConnectionException e) {
throw new MessageQueueException("Error deleting messages " + messageIds, e);
}
}
private void changeSchema(Callable<Void> callable) throws MessageQueueException {
for (int i = 0; i < 3; i++) {
try {
callable.call();
try {
Thread.sleep(SCHEMA_CHANGE_DELAY);
} catch (InterruptedException ie) {
Thread.currentThread().interrupt();
throw new MessageQueueException(
"Interrupted while trying to create column family for queue " + getName(), ie);
}
return;
} catch (SchemaDisagreementException e) {
try {
Thread.sleep(SCHEMA_CHANGE_DELAY);
} catch (InterruptedException ie) {
Thread.currentThread().interrupt();
throw new MessageQueueException(
"Interrupted while trying to create column family for queue " + getName(), ie);
}
} catch (Exception e) {
if (e.getMessage().contains("already exist")) return;
throw new MessageQueueException(
"Failed to create column family for " + queueColumnFamily.getName(), e);
}
}
}
@Override
public void createStorage() throws MessageQueueException {
changeSchema(
new Callable<Void>() {
@Override
public Void call() throws Exception {
keyspace.createColumnFamily(
queueColumnFamily,
ImmutableMap.<String, Object>builder()
.put("key_validation_class", "UTF8Type")
.put(
"comparator_type",
"CompositeType(BytesType, BytesType(reversed=true), TimeUUIDType, TimeUUIDType, BytesType)")
.putAll(columnFamilySettings)
.build());
return null;
}
});
changeSchema(
new Callable<Void>() {
@Override
public Void call() throws Exception {
keyspace.createColumnFamily(
keyIndexColumnFamily,
ImmutableMap.<String, Object>builder()
.put("key_validation_class", "UTF8Type")
.put("comparator_type", "CompositeType(BytesType, UTF8Type)")
.putAll(columnFamilySettings)
.build());
return null;
}
});
changeSchema(
new Callable<Void>() {
@Override
public Void call() throws Exception {
keyspace.createColumnFamily(
historyColumnFamily,
ImmutableMap.<String, Object>builder()
.put("default_validation_class", "UTF8Type")
.putAll(columnFamilySettings)
.build());
return null;
}
});
}
@Override
public void dropStorage() throws MessageQueueException {
try {
keyspace.dropColumnFamily(this.queueColumnFamily);
try {
Thread.sleep(SCHEMA_CHANGE_DELAY);
} catch (InterruptedException e) {
}
} catch (ConnectionException e) {
if (!e.getMessage().contains("already exist"))
throw new MessageQueueException(
"Failed to create column family for " + queueColumnFamily.getName(), e);
}
try {
keyspace.dropColumnFamily(this.keyIndexColumnFamily);
try {
Thread.sleep(SCHEMA_CHANGE_DELAY);
} catch (InterruptedException e) {
}
} catch (ConnectionException e) {
if (!e.getMessage().contains("already exist"))
throw new MessageQueueException(
"Failed to create column family for " + queueColumnFamily.getName(), e);
}
}
@Override
public void createQueue() throws MessageQueueException {
try {
// Convert the message object to JSON
ByteArrayOutputStream baos = new ByteArrayOutputStream();
mapper.writeValue(baos, metadata);
baos.flush();
keyspace
.prepareColumnMutation(queueColumnFamily, getName(), MessageQueueEntry.newMetadataEntry())
.putValue(baos.toByteArray(), null)
.execute();
} catch (ConnectionException e) {
throw new MessageQueueException(
"Failed to create column family for " + queueColumnFamily.getName(), e);
} catch (Exception e) {
throw new MessageQueueException(
"Error serializing queue settings " + queueColumnFamily.getName(), e);
}
}
@Override
public MessageConsumer createConsumer() {
return new MessageConsumerImpl(this);
}
@Override
public MessageProducer createProducer() {
return new MessageProducer() {
@Override
public String sendMessage(Message message) throws MessageQueueException {
SendMessageResponse response = sendMessages(Lists.newArrayList(message));
if (!response.getNotUnique().isEmpty())
throw new KeyExistsException("Key already exists ." + message.getKey());
return Iterables.getFirst(response.getMessages().entrySet(), null).getKey();
}
@Override
public SendMessageResponse sendMessages(Collection<Message> messages)
throws MessageQueueException {
Map<String, Message> uniqueKeys = Maps.newHashMap();
Set<String> notUniqueKeys = Sets.newHashSet();
List<Message> notUniqueMessages = Lists.newArrayList();
MutationBatch mb = keyspace.prepareMutationBatch().setConsistencyLevel(consistencyLevel);
MessageMetadataEntry lockColumn = MessageMetadataEntry.newUnique();
// Get list of keys that must be unique and prepare the mutation for phase 1
for (Message message : messages) {
if (message.hasUniqueKey()) {
String groupKey = getCompositeKey(getName(), message.getKey());
uniqueKeys.put(groupKey, message);
mb.withRow(keyIndexColumnFamily, groupKey)
.putEmptyColumn(lockColumn, (Integer) lockTtl);
}
}
// We have some keys that need to be unique
if (!uniqueKeys.isEmpty()) {
// Submit phase 1: Create a unique column for ALL of the unique keys
try {
mb.execute();
} catch (ConnectionException e) {
throw new MessageQueueException(
"Failed to check keys for uniqueness (1): " + uniqueKeys, e);
}
// Phase 2: Read back ALL the lock columms
mb = keyspace.prepareMutationBatch().setConsistencyLevel(consistencyLevel);
Rows<String, MessageMetadataEntry> result;
try {
result =
keyspace
.prepareQuery(keyIndexColumnFamily)
.setConsistencyLevel(consistencyLevel)
.getRowSlice(uniqueKeys.keySet())
.withColumnRange(
metadataSerializer
.buildRange()
.greaterThanEquals((byte) MessageMetadataEntryType.Unique.ordinal())
.lessThanEquals((byte) MessageMetadataEntryType.Unique.ordinal())
.build())
.execute()
.getResult();
} catch (ConnectionException e) {
throw new MessageQueueException(
"Failed to check keys for uniqueness (2): " + uniqueKeys, e);
}
for (Row<String, MessageMetadataEntry> row : result) {
// This key is already taken, roll back the check
if (row.getColumns().size() != 1) {
String messageKey = splitCompositeKey(row.getKey())[1];
notUniqueKeys.add(messageKey);
notUniqueMessages.add(uniqueKeys.get(messageKey));
mb.withRow(keyIndexColumnFamily, row.getKey()).deleteColumn(lockColumn);
}
// This key is now unique
else {
mb.withRow(keyIndexColumnFamily, row.getKey()).putEmptyColumn(lockColumn);
}
}
}
// Commit the messages
Map<String, Message> success = Maps.newLinkedHashMap();
for (Message message : messages) {
if (message.hasKey() && notUniqueKeys.contains(message.getKey())) continue;
String messageId = fillMessageMutation(mb, message);
success.put(messageId, message);
}
try {
mb.execute();
} catch (ConnectionException e) {
throw new MessageQueueException("Failed to insert messages into queue.", e);
}
return new SendMessageResponse(success, notUniqueMessages);
}
};
}
String fillMessageMutation(MutationBatch mb, Message message) throws MessageQueueException {
// Get the execution time from the message or set to current time so it runs immediately
long curTimeMicros;
if (!message.hasTrigger()) {
curTimeMicros =
TimeUnit.MICROSECONDS.convert(System.currentTimeMillis(), TimeUnit.MILLISECONDS);
} else {
curTimeMicros =
TimeUnit.MICROSECONDS.convert(
message.getTrigger().getTriggerTime(), TimeUnit.MILLISECONDS);
}
curTimeMicros += (counter.incrementAndGet() % 1000);
// Update the message for the new token
message.setToken(TimeUUIDUtils.getMicrosTimeUUID(curTimeMicros));
// Set up the queue entry
MessageQueueEntry entry =
MessageQueueEntry.newMessageEntry(
message.getPriority(), message.getToken(), MessageQueueEntryState.Waiting);
// Convert the message object to JSON
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
mapper.writeValue(baos, message);
baos.flush();
} catch (Exception e) {
throw new MessageQueueException("Failed to serialize message data: " + message, e);
}
// Write the queue entry
String shardKey = getShardKey(message);
mb.withRow(queueColumnFamily, shardKey)
.putColumn(entry, new String(baos.toByteArray()), metadata.getRetentionTimeout());
// Write the lookup from queue key to queue entry
if (message.hasKey()) {
mb.withRow(keyIndexColumnFamily, getCompositeKey(getName(), message.getKey()))
.putEmptyColumn(
MessageMetadataEntry.newMessageId(getCompositeKey(shardKey, entry.getMessageId())),
metadata.getRetentionTimeout());
}
// Allow hook processing
for (MessageQueueHooks hook : hooks) {
hook.beforeSendMessage(message, mb);
}
// Update state and retun the token
stats.incSendMessageCount();
return getCompositeKey(shardKey, entry.getMessageId());
}
/**
* Return history for a single key for the specified time range
*
* <p>TODO: honor the time range :)
*/
@Override
public List<MessageHistory> getKeyHistory(String key, Long startTime, Long endTime, int count)
throws MessageQueueException {
List<MessageHistory> list = Lists.newArrayList();
ColumnList<UUID> columns;
try {
columns =
keyspace
.prepareQuery(historyColumnFamily)
.setConsistencyLevel(consistencyLevel)
.getRow(key)
.execute()
.getResult();
} catch (ConnectionException e) {
throw new MessageQueueException("Failed to load history for " + key, e);
}
for (Column<UUID> column : columns) {
try {
list.add(deserializeString(column.getStringValue(), MessageHistory.class));
} catch (Exception e) {
LOG.info("Error deserializing history entry", e);
}
}
return list;
}
/**
* Iterate through shards attempting to extract itemsToPeek items. Will return once itemToPeek
* items have been read or all shards have been checked.
*
* <p>Note that this call does not take into account the message trigger time and will likely
* return messages that aren't due to be executed yet.
*
* @return List of items
*/
@Override
public List<Message> peekMessages(int itemsToPeek) throws MessageQueueException {
List<Message> messages = Lists.newArrayList();
for (MessageQueueShard shard : shardReaderPolicy.listShards()) {
messages.addAll(peekMessages(shard.getName(), itemsToPeek - messages.size()));
if (messages.size() == itemsToPeek) return messages;
}
return messages;
}
/**
* Peek into messages contained in the shard. This call does not take trigger time into account
* and will return messages that are not yet due to be executed
*
* @param shardName
* @param itemsToPop
* @return
* @throws MessageQueueException
*/
private Collection<Message> peekMessages(String shardName, int itemsToPeek)
throws MessageQueueException {
try {
ColumnList<MessageQueueEntry> result =
keyspace
.prepareQuery(queueColumnFamily)
.setConsistencyLevel(consistencyLevel)
.getKey(shardName)
.withColumnRange(
new RangeBuilder()
.setLimit(itemsToPeek)
.setStart(
entrySerializer
.makeEndpoint(
(byte) MessageQueueEntryType.Message.ordinal(),
Equality.GREATER_THAN_EQUALS)
.toBytes())
.setEnd(
entrySerializer
.makeEndpoint(
(byte) MessageQueueEntryType.Message.ordinal(),
Equality.LESS_THAN_EQUALS)
.toBytes())
.build())
.execute()
.getResult();
List<Message> messages = Lists.newArrayListWithCapacity(result.size());
for (Column<MessageQueueEntry> column : result) {
Message message = extractMessageFromColumn(column);
if (message != null) messages.add(message);
}
return messages;
} catch (ConnectionException e) {
throw new MessageQueueException("Error peeking for messages from shard " + shardName, e);
}
}
/**
* Extract a message body from a column
*
* @param column
* @return
*/
Message extractMessageFromColumn(Column<MessageQueueEntry> column) {
// Next, parse the message metadata and add a timeout entry
Message message = null;
try {
ByteArrayInputStream bais = new ByteArrayInputStream(column.getByteArrayValue());
message = mapper.readValue(bais, Message.class);
} catch (Exception e) {
LOG.warn("Error processing message ", e);
try {
message = invalidMessageHandler.apply(column.getStringValue());
} catch (Exception e2) {
LOG.warn("Error processing invalid message", e2);
}
}
return message;
}
/**
* Fast check to see if a shard has messages to process
*
* @param shardName
* @throws MessageQueueException
*/
private boolean hasMessages(String shardName) throws MessageQueueException {
UUID currentTime = TimeUUIDUtils.getUniqueTimeUUIDinMicros();
try {
ColumnList<MessageQueueEntry> result =
keyspace
.prepareQuery(queueColumnFamily)
.setConsistencyLevel(consistencyLevel)
.getKey(shardName)
.withColumnRange(
new RangeBuilder()
.setLimit(1) // Read extra messages because of the lock column
.setStart(
entrySerializer
.makeEndpoint(
(byte) MessageQueueEntryType.Message.ordinal(), Equality.EQUAL)
.toBytes())
.setEnd(
entrySerializer
.makeEndpoint(
(byte) MessageQueueEntryType.Message.ordinal(), Equality.EQUAL)
.append((byte) 0, Equality.EQUAL)
.append(currentTime, Equality.LESS_THAN_EQUALS)
.toBytes())
.build())
.execute()
.getResult();
return !result.isEmpty();
} catch (ConnectionException e) {
throw new MessageQueueException("Error checking shard for messages. " + shardName, e);
}
}
@Override
public Map<String, MessageQueueShardStats> getShardStats() {
return shardReaderPolicy.getShardStats();
}
public ShardReaderPolicy getShardReaderPolicy() {
return shardReaderPolicy;
}
public ColumnFamily<String, MessageQueueEntry> getQueueColumnFamily() {
return this.queueColumnFamily;
}
public ColumnFamily<String, MessageMetadataEntry> getKeyIndexColumnFamily() {
return this.keyIndexColumnFamily;
}
public ColumnFamily<String, UUID> getHistoryColumnFamily() {
return this.historyColumnFamily;
}
}
