lianetm commented on code in PR #16885:
URL: https://github.com/apache/kafka/pull/16885#discussion_r1724977673
##########
clients/src/main/java/org/apache/kafka/clients/consumer/internals/events/ApplicationEventProcessor.java:
##########
@@ -256,14 +271,176 @@ private void process(final UnsubscribeEvent event) {
}
}
- private void process(final ResetPositionsEvent event) {
- CompletableFuture<Void> future =
requestManagers.offsetsRequestManager.resetPositionsIfNeeded();
- future.whenComplete(complete(event.future()));
+ /**
+ *
+ * Fetch committed offsets and use them to update positions in the
subscription state. If no
+ * committed offsets available, fetch offsets from the leader.
+ */
+ private void process(final UpdateFetchPositionsEvent
updateFetchPositionsEvent) {
+ try {
+ // The event could be completed in the app thread before it got to
be
+ // processed in the background (ex. interrupted)
+ if (updateFetchPositionsEvent.future().isCompletedExceptionally())
{
+ log.debug("UpdateFetchPositions event {} was completed
exceptionally before it " +
+ "got time to be processed.", updateFetchPositionsEvent);
+ return;
+ }
+
+ // Validate positions using the partition leader end offsets, to
detect if any partition
+ // has been truncated due to a leader change. This will trigger an
OffsetForLeaderEpoch
+ // request, retrieve the partition end offsets, and validate the
current position
+ // against it. It will throw an exception if log truncation is
detected.
+ requestManagers.offsetsRequestManager.validatePositionsIfNeeded();
+
+ boolean hasAllFetchPositions =
subscriptions.hasAllFetchPositions();
+ if (hasAllFetchPositions) {
+ updateFetchPositionsEvent.future().complete(true);
+ return;
+ }
+
+ // Reset positions using committed offsets retrieved from the
group coordinator, for any
+ // partitions which do not have a valid position and are not
awaiting reset. This will
+ // trigger an OffsetFetch request and update positions with the
offsets retrieved. This
+ // will only do a coordinator lookup if there are partitions which
have missing
+ // positions, so a consumer with manually assigned partitions can
avoid a coordinator
+ // dependence by always ensuring that assigned partitions have an
initial position.
+ if (requestManagers.commitRequestManager.isPresent()) {
+ CompletableFuture<Void> initWithCommittedOffsetsResult =
initWithCommittedOffsetsIfNeeded(updateFetchPositionsEvent);
+ initWithCommittedOffsetsResult.whenComplete((__, error) -> {
+ if (error == null) {
+ // Retrieve partition offsets to init positions for
partitions that still
+ // don't have a valid position
+
initWithPartitionOffsetsIfNeeded(updateFetchPositionsEvent);
+ } else {
+
updateFetchPositionsEvent.future().completeExceptionally(error);
+ }
+ });
+ } else {
+ initWithPartitionOffsetsIfNeeded(updateFetchPositionsEvent);
+ }
+
+ } catch (Exception e) {
+
updateFetchPositionsEvent.future().completeExceptionally(maybeWrapAsKafkaException(e));
+ }
}
- private void process(final ValidatePositionsEvent event) {
- CompletableFuture<Void> future =
requestManagers.offsetsRequestManager.validatePositionsIfNeeded();
- future.whenComplete(complete(event.future()));
+ private void initWithPartitionOffsetsIfNeeded(final
UpdateFetchPositionsEvent updateFetchPositionsEvent) {
+ try {
+ // If there are partitions still needing a position and a reset
policy is defined,
+ // request reset using the default policy. If no reset strategy is
defined and there
+ // are partitions with a missing position, then we will raise a
NoOffsetForPartitionException exception.
+ subscriptions.resetInitializingPositions();
+
+ // Reset positions using partition offsets retrieved from the
leader, for any partitions
+ // which are awaiting reset. This will trigger a ListOffset
request, retrieve the
+ // partition offsets according to the strategy (ex. earliest,
latest), and update the
+ // positions.
+ CompletableFuture<Void> resetPositionsFuture =
requestManagers.offsetsRequestManager.resetPositionsIfNeeded();
+
+ resetPositionsFuture.whenComplete((result, error) -> {
+ if (updateFetchPositionsEvent.future().isDone()) {
+ log.debug("UpdateFetchPositions event {} had already
expired when reset " +
+ "positions completed.", updateFetchPositionsEvent);
+ return;
+ }
+ if (error == null) {
+ updateFetchPositionsEvent.future().complete(false);
+ } else {
+
updateFetchPositionsEvent.future().completeExceptionally(error);
+ }
+ });
+ } catch (Exception e) {
+ updateFetchPositionsEvent.future().completeExceptionally(e);
+ }
+ }
+
+ /**
+ * Fetch the committed offsets for partitions that require initialization.
Use them to set
+ * the fetch positions in the subscription state.
+ *
+ * @throws TimeoutException If offsets could not be retrieved within the
timeout
+ */
+ private CompletableFuture<Void>
initWithCommittedOffsetsIfNeeded(UpdateFetchPositionsEvent
updateFetchPositionsEvent) {
+ final Set<TopicPartition> initializingPartitions =
subscriptions.initializingPartitions();
+
+ if (initializingPartitions.isEmpty()) {
+ return CompletableFuture.completedFuture(null);
+ }
+
+ log.debug("Refreshing committed offsets for partitions {}",
initializingPartitions);
+ CompletableFuture<Void> result = new CompletableFuture<>();
+
+ // The shorter the timeout provided to poll(), the more likely the
offsets fetch will time out. To handle
+ // this case, on the first attempt to fetch the committed offsets, a
FetchCommittedOffsetsEvent is created
+ // (with potentially a longer timeout) and stored. The event is used
for the first attempt, but in the
+ // case it times out, subsequent attempts will also use the event in
order to wait for the results.
+ if (!canReusePendingOffsetFetchEvent(initializingPartitions)) {
+ final long deadlineMs =
Math.max(updateFetchPositionsEvent.deadlineMs(),
updateFetchPositionsEvent.fetchOffsetsDeadlineMs());
Review Comment:
I totally get your point. The alternative was to get the config for
"defaultApiTimeout" in the UpdateFetchPositionsEvent (that's what we need for
the 2nd deadline). This is changing now anyways, because of the changes to
address other comments, so we won't have it anymore.
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