topic operator deleted topic

[lanzhiwang]

In our k8s cluster, we deployed the strimzi kafka operator, the version is 0.18.0, we created kafka and the corresponding topic, after running for a while, we found that one of the topics was deleted, by looking for logs and codes, we found The delete operation was indeed triggered, and the relevant logs are as follows:

[2023-08-14 10:19:26,821] INFO  <opicOperator:535> [oop-thread-1] 1761157|periodic kafka xxxxxx: Reconciling topic xxxxxx, k8sTopic:null, kafkaTopic:nonnull, privateTopic:nonnull
[2023-08-14 10:19:26,822] INFO  <opicOperator:361> [oop-thread-1] 1761157|periodic kafka xxxxxx: Deleting topic 'xxxxxx'

This log shows that the corresponding delete operation was indeed triggered, and the corresponding code is as follows:

    Future<Void> reconcile(Reconciliation reconciliation, final LogContext logContext, final HasMetadata involvedObject,
                   final Topic k8sTopic, final Topic kafkaTopic, final Topic privateTopic) {
        final Future<Void> reconciliationResultHandler;
        {
            TopicName topicName = k8sTopic != null ? k8sTopic.getTopicName() : kafkaTopic != null ? kafkaTopic.getTopicName() : privateTopic != null ? privateTopic.getTopicName() : null;
            LOGGER.info("{}: Reconciling topic {}, k8sTopic:{}, kafkaTopic:{}, privateTopic:{}", logContext, topicName, k8sTopic == null ? "null" : "nonnull", kafkaTopic == null ? "null" : "nonnull", privateTopic == null ? "null" : "nonnull");
        }
        if (privateTopic == null) {
            if (k8sTopic == null) {
                if (kafkaTopic == null) {
                    // All three null: This happens reentrantly when a topic or KafkaTopic is deleted
                    LOGGER.debug("{}: All three topics null during reconciliation.", logContext);
                    reconciliationResultHandler = Future.succeededFuture();
                } else {
                    // it's been created in Kafka => create in k8s and privateState
                    LOGGER.debug("{}: topic created in kafka, will create KafkaTopic in k8s and topicStore", logContext);
                    reconciliationResultHandler = createResource(logContext, kafkaTopic)
                            .compose(createdKt -> {
                                reconciliation.observedTopicFuture(createdKt);
                                return createInTopicStore(logContext, kafkaTopic, involvedObject);
                            });
                }
            } else if (kafkaTopic == null) {
                // it's been created in k8s => create in Kafka and privateState
                LOGGER.debug("{}: KafkaTopic created in k8s, will create topic in kafka and topicStore", logContext);
                reconciliationResultHandler = createKafkaTopic(logContext, k8sTopic, involvedObject)
                    .compose(ignore -> createInTopicStore(logContext, k8sTopic, involvedObject))
                    // Kafka will set the message.format.version, so we need to update the KafkaTopic to reflect
                    // that to avoid triggering another reconciliation
                    .compose(ignored -> getFromKafka(k8sTopic.getTopicName()))
                    .compose(kafkaTopic2 -> {
                        LOGGER.debug("Post-create kafka {}", kafkaTopic2);
                        if (kafkaTopic2 == null) {
                            LOGGER.error("Post-create kafka unexpectedly null");
                            return Future.succeededFuture();
                        }
                        return update3Way(reconciliation, logContext, involvedObject, k8sTopic, kafkaTopic2, k8sTopic);
                    });
                    //.compose(createdKafkaTopic -> update3Way(logContext, involvedObject, k8sTopic, createdKafkaTopic, k8sTopic));
            } else {
                reconciliationResultHandler = update2Way(reconciliation, logContext, involvedObject, k8sTopic, kafkaTopic);
            }
        } else {
            if (k8sTopic == null) {
                if (kafkaTopic == null) {
                    // delete privateState
                    LOGGER.debug("{}: KafkaTopic deleted in k8s and topic deleted in kafka => delete from topicStore", logContext);
                    reconciliationResultHandler = deleteFromTopicStore(logContext, involvedObject, privateTopic.getTopicName());
                } else {
                    // it was deleted in k8s so delete in kafka and privateState
                    // If delete.topic.enable=false then the resulting exception will be ignored and only the privateState topic will be deleted
                    LOGGER.debug("{}: KafkaTopic deleted in k8s => delete topic from kafka and from topicStore", logContext);
                    reconciliationResultHandler = deleteKafkaTopic(logContext, kafkaTopic.getTopicName()).recover(this::handleTopicDeletionDisabled)
                        .compose(ignored -> deleteFromTopicStore(logContext, involvedObject, privateTopic.getTopicName()));
                }
            } else if (kafkaTopic == null) {
                // it was deleted in kafka so delete in k8s and privateState
                LOGGER.debug("{}: topic deleted in kafkas => delete KafkaTopic from k8s and from topicStore", logContext);
                reconciliationResultHandler = deleteResource(logContext, privateTopic.getOrAsKubeName())
                        .compose(ignore -> {
                            reconciliation.observedTopicFuture(null);
                            return deleteFromTopicStore(logContext, involvedObject, privateTopic.getTopicName());
                        });
            } else {
                // all three exist
                LOGGER.debug("{}: 3 way diff", logContext);
                reconciliationResultHandler = update3Way(reconciliation, logContext, involvedObject,
                        k8sTopic, kafkaTopic, privateTopic);
            }
        }
        return reconciliationResultHandler;
    }

Now I would like to ask two questions. The first is what the variables privateTopic, k8sTopic, and kafkaTopic represent and what they do. The second question is what scenario will cause k8sTopic to be null, kafkaTopic to be nonnull, and privateTopic to be nonnull

thanks!