cmccabe commented on a change in pull request #10931:
URL: https://github.com/apache/kafka/pull/10931#discussion_r663277869
##########
File path:
core/src/main/scala/kafka/server/metadata/BrokerMetadataListener.scala
##########
@@ -70,230 +58,188 @@ class BrokerMetadataListener(
*/
@volatile private var _highestMetadataOffset = -1L
+ /**
+ * The current broker metadata image. Accessed only from the event queue
thread.
+ */
+ private var _image = MetadataImage.EMPTY
+
+ /**
+ * The current metadata delta. Accessed only from the event queue thread.
+ */
+ private var _delta = new MetadataDelta(_image)
+
+ /**
+ * The object to use to publish new metadata changes, or None if this
listener has not
+ * been activated yet.
+ */
+ private var _publisher: Option[MetadataPublisher] = None
+
+ /**
+ * The event queue which runs this listener.
+ */
val eventQueue = new KafkaEventQueue(time, logContext,
threadNamePrefix.getOrElse(""))
+ /**
+ * Returns the highest metadata-offset. Thread-safe.
+ */
def highestMetadataOffset(): Long = _highestMetadataOffset
/**
* Handle new metadata records.
*/
- override def handleCommit(reader: BatchReader[ApiMessageAndVersion]): Unit =
{
+ override def handleCommit(reader: BatchReader[ApiMessageAndVersion]): Unit =
eventQueue.append(new HandleCommitsEvent(reader))
+
+ class HandleCommitsEvent(reader: BatchReader[ApiMessageAndVersion])
+ extends EventQueue.FailureLoggingEvent(log) {
+ override def run(): Unit = {
+ val results = try {
+ val loadResults = loadBatches(_delta, reader)
+ if (isDebugEnabled) {
+ debug(s"Loaded new commits: ${loadResults}")
+ }
+ loadResults
+ } finally {
+ reader.close()
+ }
+ maybePublish(results.highestMetadataOffset)
+ }
}
/**
* Handle metadata snapshots
*/
- override def handleSnapshot(reader: SnapshotReader[ApiMessageAndVersion]):
Unit = {
- // Loading snapshot on the broker is currently not supported.
- reader.close();
- throw new UnsupportedOperationException(s"Loading snapshot
(${reader.snapshotId()}) is not supported")
- }
-
- // Visible for testing. It's useful to execute events synchronously in order
- // to make tests deterministic. This object is responsible for closing the
reader.
- private[metadata] def execCommits(batchReader:
BatchReader[ApiMessageAndVersion]): Unit = {
- new HandleCommitsEvent(batchReader).run()
- }
+ override def handleSnapshot(reader: SnapshotReader[ApiMessageAndVersion]):
Unit =
+ eventQueue.append(new HandleSnapshotEvent(reader))
- class HandleCommitsEvent(
- reader: BatchReader[ApiMessageAndVersion]
- ) extends EventQueue.FailureLoggingEvent(log) {
+ class HandleSnapshotEvent(reader: SnapshotReader[ApiMessageAndVersion])
+ extends EventQueue.FailureLoggingEvent(log) {
override def run(): Unit = {
- try {
- while (reader.hasNext()) {
- apply(reader.next())
- }
+ val results = try {
+ info(s"Loading snapshot
${reader.snapshotId().offset}-${reader.snapshotId().epoch}.")
+ _delta = new MetadataDelta(_image) // Discard any previous deltas.
+ val loadResults = loadBatches(_delta, reader)
+ _delta.finishSnapshot()
Review comment:
Yeah, I thought about a few other names. Remove unreferenced? None of
them seem great...
I added some more JavaDoc to `MetadataDelta#finishSnapshot`
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