dajac commented on code in PR #14690:
URL: https://github.com/apache/kafka/pull/14690#discussion_r1394042794
##########
clients/src/main/java/org/apache/kafka/clients/consumer/internals/MembershipManagerImpl.java:
##########
@@ -181,63 +348,560 @@ public void
updateState(ConsumerGroupHeartbeatResponseData response) {
public void transitionToFenced() {
resetEpoch();
transitionTo(MemberState.FENCED);
+
+ // Release assignment
+ CompletableFuture<Void> callbackResult =
invokeOnPartitionsLostCallback(subscriptions.assignedPartitions());
+ callbackResult.whenComplete((result, error) -> {
+ if (error != null) {
+ log.debug("OnPartitionsLost callback invocation failed while
releasing assignment" +
+ "after member got fenced. Member will rejoin the group
anyways.", error);
+ }
+ subscriptions.assignFromSubscribed(Collections.emptySet());
+ transitionToJoining();
+ });
+
+ clearPendingAssignmentsAndLocalNamesCache();
}
/**
* {@inheritDoc}
*/
@Override
- public void transitionToFailed() {
- log.error("Member {} transitioned to {} state", memberId,
MemberState.FAILED);
- transitionTo(MemberState.FAILED);
+ public void transitionToFatal() {
+ log.error("Member {} transitioned to {} state", memberId,
MemberState.FATAL);
+
+ // Update epoch to indicate that the member is not in the group
anymore, so that the
+ // onPartitionsLost is called to release assignment.
+ memberEpoch = ConsumerGroupHeartbeatRequest.LEAVE_GROUP_MEMBER_EPOCH;
+ invokeOnPartitionsLostCallback(subscriptions.assignedPartitions());
+
+ clearPendingAssignmentsAndLocalNamesCache();
+ transitionTo(MemberState.FATAL);
}
+ /**
+ * {@inheritDoc}
+ */
@Override
- public boolean shouldSendHeartbeat() {
- return state() != MemberState.FAILED;
+ public void transitionToJoining() {
+ resetEpoch();
+ transitionTo(MemberState.JOINING);
+ clearPendingAssignmentsAndLocalNamesCache();
+ // Reset member ID of the reconciliation in progress (if any), to make
sure that if the
+ // reconciliation completes while the member is rejoining but hasn't
received the new
+ // member ID yet, the reconciliation result is discarded.
+ memberIdOnReconciliationStart = null;
}
/**
- * Transition to {@link MemberState#STABLE} only if there are no target
assignments left to
- * reconcile. Transition to {@link MemberState#RECONCILING} otherwise.
+ * {@inheritDoc}
*/
- private boolean maybeTransitionToStable() {
- if (!hasPendingTargetAssignment()) {
- transitionTo(MemberState.STABLE);
+ @Override
+ public CompletableFuture<Void> leaveGroup() {
+ transitionTo(MemberState.PREPARE_LEAVING);
+
+ CompletableFuture<Void> callbackResult =
invokeOnPartitionsRevokedOrLostToReleaseAssignment();
+ callbackResult.whenComplete((result, error) -> {
+
+ // Clear the subscription, no matter if the callback execution
failed or succeeded.
+ subscriptions.assignFromSubscribed(Collections.emptySet());
+
+ // Transition to ensure that a heartbeat request is sent out to
effectively leave the
+ // group (even in the case where the member had no assignment to
release or when the
+ // callback execution failed.)
+ transitionToSendingLeaveGroup();
+
+ });
+
+ clearPendingAssignmentsAndLocalNamesCache();
+
+ // Return callback future to indicate that the leave group is done
when the callbacks
+ // complete, without waiting for the heartbeat to be sent out. (Best
effort to send it
+ // but do not hold the leave group operation for it)
+ return callbackResult;
+ }
+
+ /**
+ * Release member assignment by calling the user defined callbacks for
onPartitionsRevoked or
+ * onPartitionsLost.
+ * <ul>
+ * <li>If the member is part of the group (epoch > 0), this will
invoke onPartitionsRevoked.
+ * This will be the case when releasing assignment because the member
is intentionally
+ * leaving the group (after a call to unsubscribe)</li>
+ *
+ * <li>If the member is not part of the group (epoch <=0), this will
invoke onPartitionsLost.
+ * This will be the case when releasing assignment after being fenced
.</li>
+ * </ul>
+ *
+ * @return Future that will complete when the callback execution completes.
+ */
+ private CompletableFuture<Void>
invokeOnPartitionsRevokedOrLostToReleaseAssignment() {
+ SortedSet<TopicPartition> droppedPartitions = new
TreeSet<>(COMPARATOR);
+ droppedPartitions.addAll(subscriptions.assignedPartitions());
+
+ CompletableFuture<Void> callbackResult;
+ if (droppedPartitions.isEmpty()) {
+ // No assignment to release
+ callbackResult = CompletableFuture.completedFuture(null);
} else {
- transitionTo(MemberState.RECONCILING);
+ // Release assignment
+ if (memberEpoch > 0) {
+ // Member is part of the group. Invoke onPartitionsRevoked.
+ callbackResult = revokePartitions(droppedPartitions);
+ } else {
+ // Member is not part of the group anymore. Invoke
onPartitionsLost.
+ callbackResult =
invokeOnPartitionsLostCallback(droppedPartitions);
+ }
+ // Remove all topic IDs and names from local cache
+ callbackResult.whenComplete((result, error) ->
clearPendingAssignmentsAndLocalNamesCache());
+ }
+ return callbackResult;
+ }
+
+ /**
+ * Reset member epoch to the value required for the leave the group
heartbeat request, and
+ * transition to the {@link MemberState#LEAVING} state so that a heartbeat
+ * request is sent out with it.
+ */
+ private void transitionToSendingLeaveGroup() {
+ memberEpoch = ConsumerGroupHeartbeatRequest.LEAVE_GROUP_MEMBER_EPOCH;
+ currentAssignment = new HashSet<>();
+ transitionTo(MemberState.LEAVING);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean shouldHeartbeatNow() {
+ MemberState state = state();
+ return state == MemberState.ACKNOWLEDGING || state ==
MemberState.LEAVING;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void onHeartbeatRequestSent() {
+ MemberState state = state();
+ if (state == MemberState.ACKNOWLEDGING) {
+ if (allPendingAssignmentsReconciled()) {
+ transitionTo(MemberState.STABLE);
+ } else {
+ transitionTo(MemberState.RECONCILING);
+ }
+ } else if (state == MemberState.LEAVING) {
+ transitionTo(MemberState.UNSUBSCRIBED);
}
- return state.equals(MemberState.STABLE);
}
/**
- * Take new target assignment received from the server and set it as
targetAssignment to be
- * processed. Following the consumer group protocol, the server won't send
a new target
- * member while a previous one hasn't been acknowledged by the member, so
this will fail
- * if a target assignment already exists.
+ * @return True if there are no assignments waiting to be resolved from
metadata or reconciled.
+ */
+ private boolean allPendingAssignmentsReconciled() {
+ return assignmentUnresolved.isEmpty() &&
assignmentReadyToReconcile.isEmpty();
+ }
+
+ @Override
+ public boolean shouldSkipHeartbeat() {
+ MemberState state = state();
+ return state == MemberState.UNSUBSCRIBED || state == MemberState.FATAL;
+ }
+
+ /**
+ * Reconcile the assignment that has been received from the server and for
which topic names
+ * are resolved, kept in the {@link #assignmentReadyToReconcile}. This
will commit if needed,
+ * trigger the callbacks and update the subscription state. Note that only
one reconciliation
+ * can be in progress at a time. If there is already another one in
progress when this is
+ * triggered, it will be no-op, and the assignment will be reconciled on
the next
+ * reconciliation loop.
+ */
+ boolean reconcile() {
+ // Make copy of the assignment to reconcile as it could change as new
assignments or metadata updates are received
+ SortedSet<TopicPartition> assignedPartitions = new
TreeSet<>(COMPARATOR);
+ assignedPartitions.addAll(assignmentReadyToReconcile);
+
+ SortedSet<TopicPartition> ownedPartitions = new TreeSet<>(COMPARATOR);
+ ownedPartitions.addAll(subscriptions.assignedPartitions());
+
+ boolean sameAssignmentReceived =
assignedPartitions.equals(ownedPartitions);
+
+ if (reconciliationInProgress || sameAssignmentReceived) {
+ String reason;
+ if (reconciliationInProgress) {
+ reason = "Another reconciliation is already in progress.
Assignment " +
+ assignmentReadyToReconcile + " will be handled in the
next reconciliation loop.";
+ } else {
+ reason = "Target assignment ready to reconcile is equals to
the member current assignment.";
+ }
+ log.debug("Ignoring reconciliation attempt. " + reason);
+ return false;
+ }
+
+ markReconciliationInProgress();
+
+
+ // Partitions to assign (not previously owned)
+ SortedSet<TopicPartition> addedPartitions = new TreeSet<>(COMPARATOR);
+ addedPartitions.addAll(assignedPartitions);
+ addedPartitions.removeAll(ownedPartitions);
+
+ // Partitions to revoke
+ SortedSet<TopicPartition> revokedPartitions = new
TreeSet<>(COMPARATOR);
+ revokedPartitions.addAll(ownedPartitions);
+ revokedPartitions.removeAll(assignedPartitions);
+
+ log.info("Updating assignment with\n" +
+ "\tAssigned partitions: {}\n" +
+ "\tCurrent owned partitions: {}\n" +
+ "\tAdded partitions (assigned - owned): {}\n" +
+ "\tRevoked partitions (owned - assigned): {}\n",
+ assignedPartitions,
+ ownedPartitions,
+ addedPartitions,
+ revokedPartitions
+ );
+
+ CompletableFuture<Void> revocationResult;
+ if (!revokedPartitions.isEmpty()) {
+ revocationResult = revokePartitions(revokedPartitions);
Review Comment:
I also wonder whether if would be possible to parallelize more. For
instance, is there a reason not to trigger the revocation and the assignment
callbacks at the same time? This would ensure that they are call within one
poll; otherwise, it can take multiple calls to poll to complete the assignment.
We could consider this as a optimization for the future.
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