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new b43be1d0e4 NIFI-15563 Added Current Lag gauge recording to ConsumeKafka
b43be1d0e4 is described below
commit b43be1d0e462ead0c593d65c1a15107fb70e3ae0
Author: Lukas Kucharski <[email protected]>
AuthorDate: Fri Feb 6 21:31:53 2026 +0100
NIFI-15563 Added Current Lag gauge recording to ConsumeKafka
This closes #10880
Signed-off-by: David Handermann <[email protected]>
---
.../nifi/kafka/processors/ConsumeKafkaIT.java | 34 ++++++++++
.../apache/nifi/kafka/processors/ConsumeKafka.java | 73 +++++++++++++++++++++-
2 files changed, 106 insertions(+), 1 deletion(-)
diff --git
a/nifi-extension-bundles/nifi-kafka-bundle/nifi-kafka-3-integration/src/test/java/org/apache/nifi/kafka/processors/ConsumeKafkaIT.java
b/nifi-extension-bundles/nifi-kafka-bundle/nifi-kafka-3-integration/src/test/java/org/apache/nifi/kafka/processors/ConsumeKafkaIT.java
index e4e12898e3..8bed57a9a9 100644
---
a/nifi-extension-bundles/nifi-kafka-bundle/nifi-kafka-3-integration/src/test/java/org/apache/nifi/kafka/processors/ConsumeKafkaIT.java
+++
b/nifi-extension-bundles/nifi-kafka-bundle/nifi-kafka-3-integration/src/test/java/org/apache/nifi/kafka/processors/ConsumeKafkaIT.java
@@ -40,6 +40,7 @@ import java.util.Iterator;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.ExecutionException;
+import java.util.stream.IntStream;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -52,6 +53,8 @@ class ConsumeKafkaIT extends AbstractConsumeKafkaIT {
private static final long FIRST_OFFSET = 0;
+ private static final String METRIC_CURRENT_LAG_RECORDS =
"topic.%s.partition.%d.currentLagRecords";
+
private TestRunner runner;
@BeforeEach
@@ -254,6 +257,37 @@ class ConsumeKafkaIT extends AbstractConsumeKafkaIT {
runner.assertAllFlowFilesTransferred(ConsumeKafka.SUCCESS, 1);
}
+ @Test
+ @Timeout(30)
+ public void testLagReporting() throws ExecutionException,
InterruptedException {
+ final String topic = "testLagReporting";
+ final int partition = 0;
+ final int maxPollRecords = 2;
+
+ runner.setProperty(ConsumeKafka.GROUP_ID, "testLagReportingGroup");
+ runner.setProperty(ConsumeKafka.TOPICS, topic);
+ runner.setProperty(ConsumeKafka.PROCESSING_STRATEGY,
ProcessingStrategy.FLOW_FILE.getValue());
+ runner.setProperty(ConsumeKafka.MAX_UNCOMMITTED_TIME, "1000 millis");
+
+ final ControllerService connectionService =
runner.getControllerService(CONNECTION_SERVICE_ID);
+ runner.disableControllerService(connectionService);
+ runner.setProperty(connectionService,
Kafka3ConnectionService.MAX_POLL_RECORDS, Integer.toString(maxPollRecords));
+ runner.enableControllerService(connectionService);
+
+ final List<ProducerRecord<String, String>> records =
IntStream.range(0, 1000)
+ .mapToObj(i -> new ProducerRecord<>(topic, partition, "key" +
i, "val" + i))
+ .toList();
+ produce(topic, records);
+
+ final String gaugeName = METRIC_CURRENT_LAG_RECORDS.formatted(topic,
partition);
+ runner.run(1, false, true);
+
+ // consume until at least one gauge with lag gets recorded
+ while (runner.getGaugeValues(gaugeName).isEmpty()) {
+ runner.run(1, false, false);
+ }
+ }
+
@Timeout(5)
@Test
void testMaxUncommittedSize() throws InterruptedException,
ExecutionException {
diff --git
a/nifi-extension-bundles/nifi-kafka-bundle/nifi-kafka-processors/src/main/java/org/apache/nifi/kafka/processors/ConsumeKafka.java
b/nifi-extension-bundles/nifi-kafka-bundle/nifi-kafka-processors/src/main/java/org/apache/nifi/kafka/processors/ConsumeKafka.java
index b92bd862a3..f56cb2d089 100644
---
a/nifi-extension-bundles/nifi-kafka-bundle/nifi-kafka-processors/src/main/java/org/apache/nifi/kafka/processors/ConsumeKafka.java
+++
b/nifi-extension-bundles/nifi-kafka-bundle/nifi-kafka-processors/src/main/java/org/apache/nifi/kafka/processors/ConsumeKafka.java
@@ -41,6 +41,7 @@ import
org.apache.nifi.kafka.processors.consumer.convert.RecordStreamKafkaMessag
import
org.apache.nifi.kafka.processors.consumer.convert.WrapperRecordStreamKafkaMessageConverter;
import org.apache.nifi.kafka.service.api.KafkaConnectionService;
import org.apache.nifi.kafka.service.api.common.PartitionState;
+import org.apache.nifi.kafka.service.api.common.TopicPartitionSummary;
import org.apache.nifi.kafka.service.api.consumer.AutoOffsetReset;
import org.apache.nifi.kafka.service.api.consumer.KafkaConsumerService;
import org.apache.nifi.kafka.service.api.consumer.PollingContext;
@@ -57,6 +58,7 @@ import org.apache.nifi.processor.ProcessSession;
import org.apache.nifi.processor.Relationship;
import org.apache.nifi.processor.VerifiableProcessor;
import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.processor.metrics.CommitTiming;
import org.apache.nifi.processor.util.StandardValidators;
import org.apache.nifi.serialization.RecordReaderFactory;
import org.apache.nifi.serialization.RecordSetWriterFactory;
@@ -68,9 +70,11 @@ import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
+import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
+import java.util.OptionalLong;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.LinkedBlockingQueue;
@@ -330,6 +334,7 @@ public class ConsumeKafka extends AbstractProcessor
implements VerifiableProcess
private static final Set<Relationship> SUCCESS_RELATIONSHIP =
Set.of(SUCCESS);
private static final Set<Relationship> SUCCESS_FAILURE_RELATIONSHIPS =
Set.of(SUCCESS, PARSE_FAILURE);
+ private static final String METRIC_CURRENT_LAG_RECORDS =
"topic.%s.partition.%d.currentLagRecords";
private volatile Charset headerEncoding;
private volatile Pattern headerNamePattern;
@@ -432,7 +437,8 @@ public class ConsumeKafka extends AbstractProcessor
implements VerifiableProcess
break;
}
- final Iterator<ByteRecord> consumerRecords =
consumerService.poll(maxWaitDuration).iterator();
+ final TopicPartitionScanningIterator consumerRecords = new
TopicPartitionScanningIterator(consumerService.poll(maxWaitDuration).iterator());
+
if (!consumerRecords.hasNext()) {
getLogger().trace("No Kafka Records consumed: {}",
pollingContext);
// Check if a rebalance occurred during poll - if so,
break to commit what we have
@@ -445,6 +451,7 @@ public class ConsumeKafka extends AbstractProcessor
implements VerifiableProcess
recordsReceived = true;
processConsumerRecords(context, session, offsetTracker,
consumerRecords);
+ reportCurrentLag(consumerService, session,
consumerRecords.getTopicPartitionSummaries());
// Check if a rebalance occurred during poll - if so, break to
commit what we have
if (consumerService.hasRevokedPartitions()) {
@@ -498,6 +505,20 @@ public class ConsumeKafka extends AbstractProcessor
implements VerifiableProcess
});
}
+ private void reportCurrentLag(final KafkaConsumerService consumerService,
final ProcessSession session, final Set<TopicPartitionSummary>
topicPartitionSummaries) {
+ for (final TopicPartitionSummary topicPartitionSummary :
topicPartitionSummaries) {
+ final OptionalLong currentLag =
consumerService.currentLag(topicPartitionSummary);
+ if (currentLag.isPresent()) {
+ final String gaugeName =
getCurrentLagGaugeName(topicPartitionSummary);
+ session.recordGauge(gaugeName, currentLag.getAsLong(),
CommitTiming.NOW);
+ }
+ }
+ }
+
+ private String getCurrentLagGaugeName(final TopicPartitionSummary
topicPartitionSummary) {
+ return
METRIC_CURRENT_LAG_RECORDS.formatted(topicPartitionSummary.getTopic(),
topicPartitionSummary.getPartition());
+ }
+
private void commitOffsets(final KafkaConsumerService consumerService,
final OffsetTracker offsetTracker, final PollingContext pollingContext, final
ProcessSession session) {
try {
if (commitOffsets) {
@@ -686,4 +707,54 @@ public class ConsumeKafka extends AbstractProcessor
implements VerifiableProcess
return pollingContext;
}
+
+ static class TopicPartitionScanningIterator implements
Iterator<ByteRecord> {
+
+ private final Iterator<ByteRecord> iterator;
+ private final Set<TopicPartitionSummary> topicPartitionSummaries = new
HashSet<>();
+ private TopicPartitionSummary lastTopicPartition;
+
+ TopicPartitionScanningIterator(final Iterator<ByteRecord> iterator) {
+ this.iterator = iterator;
+ }
+
+ @Override
+ public boolean hasNext() {
+ return iterator.hasNext();
+ }
+
+ @Override
+ public ByteRecord next() {
+ final ByteRecord record = iterator.next();
+ // Avoid unnecessary TopicPartitionSummary object creation
+ if (isNewTopicPartition(record)) {
+ final TopicPartitionSummary summary = new
TopicPartitionSummary(record.getTopic(), record.getPartition());
+ topicPartitionSummaries.add(summary);
+ lastTopicPartition = summary;
+ }
+ return record;
+ }
+
+ public Set<TopicPartitionSummary> getTopicPartitionSummaries() {
+ return topicPartitionSummaries;
+ }
+
+ private boolean isNewTopicPartition(final ByteRecord record) {
+ final String topic = record.getTopic();
+ final int partition = record.getPartition();
+
+ final boolean newTopicPartition;
+ if (lastTopicPartition == null) {
+ newTopicPartition = true;
+ } else {
+ if (lastTopicPartition.getTopic().equals(topic)) {
+ newTopicPartition = lastTopicPartition.getPartition() !=
partition;
+ } else {
+ newTopicPartition = true;
+ }
+ }
+
+ return newTopicPartition;
+ }
+ }
}
