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Add ability to start reading from a custom offset in KafkaItemReader #737

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9 changes: 5 additions & 4 deletions ...ch-infrastructure/src/main/java/org/springframework/batch/item/kafka/KafkaItemReader.java
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,9 @@
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

import static java.util.Collections.emptyMap;
import static org.apache.commons.lang3.ObjectUtils.defaultIfNull;

/**
* <p>
* An {@link org.springframework.batch.item.ItemReader} implementation for Apache Kafka.
Expand All @@ -48,6 +51,7 @@
*
* @author Mathieu Ouellet
* @author Mahmoud Ben Hassine
* @author Christian Allard
* @since 4.2
*/
public class KafkaItemReader<K, V> extends AbstractItemStreamItemReader<V> {
Expand Down Expand Up @@ -144,11 +148,8 @@ public boolean isSaveState() {
public void open(ExecutionContext executionContext) {
this.kafkaConsumer = new KafkaConsumer<>(this.consumerProperties);
this.partitionOffsets = new HashMap<>();
for (TopicPartition topicPartition : this.topicPartitions) {
this.partitionOffsets.put(topicPartition, 0L);
}
if (this.saveState && executionContext.containsKey(TOPIC_PARTITION_OFFSETS)) {
Map<TopicPartition, Long> offsets = (Map<TopicPartition, Long>) executionContext.get(TOPIC_PARTITION_OFFSETS);
Map<TopicPartition, Long> offsets = defaultIfNull((Map<TopicPartition, Long>) executionContext.get(TOPIC_PARTITION_OFFSETS), emptyMap());
for (Map.Entry<TopicPartition, Long> entry : offsets.entrySet()) {
this.partitionOffsets.put(entry.getKey(), entry.getValue() == 0 ? 0 : entry.getValue() + 1);
}
Expand Down
144 changes: 125 additions & 19 deletions ...frastructure/src/test/java/org/springframework/batch/item/kafka/KafkaItemReaderTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@
/**
* @author Mathieu Ouellet
* @author Mahmoud Ben Hassine
* @author Christian Allard
*/
public class KafkaItemReaderTests {

Expand All @@ -66,8 +67,10 @@ public static void setUpTopics() {
embeddedKafka.getEmbeddedKafka().addTopics(
new NewTopic("topic1", 1, (short) 1),
new NewTopic("topic2", 2, (short) 1),
new NewTopic("topic3", 1, (short) 1),
new NewTopic("topic4", 2, (short) 1)
new NewTopic("topic3a", 1, (short) 1),
new NewTopic("topic3b", 1, (short) 1),
new NewTopic("topic4a", 2, (short) 1),
new NewTopic("topic4b", 2, (short) 1)
);
}

Expand All @@ -85,6 +88,7 @@ public void setUp() {
StringDeserializer.class.getName());
this.consumerProperties.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
StringDeserializer.class.getName());
this.consumerProperties.setProperty(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
}

@Test
Expand Down Expand Up @@ -238,7 +242,7 @@ public void testReadFromMultiplePartitions() {

@Test
public void testReadFromSinglePartitionAfterRestart() {
this.template.setDefaultTopic("topic3");
this.template.setDefaultTopic("topic3a");
this.template.sendDefault("val0");
this.template.sendDefault("val1");
this.template.sendDefault("val2");
Expand All @@ -247,15 +251,15 @@ public void testReadFromSinglePartitionAfterRestart() {

ExecutionContext executionContext = new ExecutionContext();
Map<TopicPartition, Long> offsets = new HashMap<>();
offsets.put(new TopicPartition("topic3", 0), 1L);
offsets.put(new TopicPartition("topic3a", 0), 1L);
executionContext.put("topic.partition.offsets", offsets);

// topic3-0: val0, val1, val2, val3, val4
// topic3a-0: val0, val1, val2, val3, val4
// ^
// |
// last committed offset = 1 (should restart from offset = 2)

this.reader = new KafkaItemReader<>(this.consumerProperties, "topic3", 0);
this.reader = new KafkaItemReader<>(this.consumerProperties, "topic3a", 0);
this.reader.setPollTimeout(Duration.ofSeconds(1));
this.reader.open(executionContext);

Expand All @@ -270,38 +274,80 @@ public void testReadFromSinglePartitionAfterRestart() {
this.reader.close();
}

@Test
public void testReadFromSinglePartitionAfterRestartWithoutSaveState() {
this.template.setDefaultTopic("topic3b");
this.template.sendDefault("val0");
this.template.sendDefault("val1");

this.reader = new KafkaItemReader<>(this.consumerProperties, "topic3b", 0);
this.reader.setPollTimeout(Duration.ofSeconds(1));
this.reader.open(new ExecutionContext());

List<String> items = new ArrayList<>();
items.add(this.reader.read());
items.add(this.reader.read());
assertThat(items, containsInAnyOrder("val0", "val1"));
assertNull(this.reader.read());

this.reader.close();

this.template.sendDefault("val2");
this.template.sendDefault("val3");
this.template.sendDefault("val4");

// topic3b-0: val0, val1, val2, val3, val4
// ^
// |
// last committed offset = 1 (should restart from offset = 2)

this.reader = new KafkaItemReader<>(this.consumerProperties, "topic3b", 0);
this.reader.setPollTimeout(Duration.ofSeconds(1));
this.reader.open(new ExecutionContext());

items = new ArrayList<>();
items.add(this.reader.read());
items.add(this.reader.read());
items.add(this.reader.read());
assertThat(items, containsInAnyOrder("val2", "val3", "val4"));
String item = this.reader.read();
assertNull(item);

this.reader.close();
}

@Test
public void testReadFromMultiplePartitionsAfterRestart() throws ExecutionException, InterruptedException {
List<ListenableFuture> futures = new ArrayList<>();
futures.add(this.template.send("topic4", 0, null, "val0"));
futures.add(this.template.send("topic4", 0, null, "val2"));
futures.add(this.template.send("topic4", 0, null, "val4"));
futures.add(this.template.send("topic4", 0, null, "val6"));
futures.add(this.template.send("topic4", 1, null, "val1"));
futures.add(this.template.send("topic4", 1, null, "val3"));
futures.add(this.template.send("topic4", 1, null, "val5"));
futures.add(this.template.send("topic4", 1, null, "val7"));
futures.add(this.template.send("topic4a", 0, null, "val0"));
futures.add(this.template.send("topic4a", 0, null, "val2"));
futures.add(this.template.send("topic4a", 0, null, "val4"));
futures.add(this.template.send("topic4a", 0, null, "val6"));
futures.add(this.template.send("topic4a", 1, null, "val1"));
futures.add(this.template.send("topic4a", 1, null, "val3"));
futures.add(this.template.send("topic4a", 1, null, "val5"));
futures.add(this.template.send("topic4a", 1, null, "val7"));

for (ListenableFuture future : futures) {
future.get();
}

ExecutionContext executionContext = new ExecutionContext();
Map<TopicPartition, Long> offsets = new HashMap<>();
offsets.put(new TopicPartition("topic4", 0), 1L);
offsets.put(new TopicPartition("topic4", 1), 2L);
offsets.put(new TopicPartition("topic4a", 0), 1L);
offsets.put(new TopicPartition("topic4a", 1), 2L);
executionContext.put("topic.partition.offsets", offsets);

// topic4-0: val0, val2, val4, val6
// topic4a-0: val0, val2, val4, val6
// ^
// |
// last committed offset = 1 (should restart from offset = 2)
// topic4-1: val1, val3, val5, val7
// topic4a-1: val1, val3, val5, val7
// ^
// |
// last committed offset = 2 (should restart from offset = 3)

this.reader = new KafkaItemReader<>(this.consumerProperties, "topic4", 0, 1);
this.reader = new KafkaItemReader<>(this.consumerProperties, "topic4a", 0, 1);
this.reader.setPollTimeout(Duration.ofSeconds(1));
this.reader.open(executionContext);

Expand All @@ -316,4 +362,64 @@ public void testReadFromMultiplePartitionsAfterRestart() throws ExecutionExcepti
this.reader.close();
}

@Test
public void testReadFromMultiplePartitionsAfterRestartWithoutSaveState() throws ExecutionException, InterruptedException {
List<ListenableFuture> futures = new ArrayList<>();
futures.add(this.template.send("topic4b", 0, null, "val0"));
futures.add(this.template.send("topic4b", 0, null, "val2"));
futures.add(this.template.send("topic4b", 1, null, "val1"));
futures.add(this.template.send("topic4b", 1, null, "val3"));
futures.add(this.template.send("topic4b", 1, null, "val5"));

for (ListenableFuture future : futures) {
future.get();
}

this.reader = new KafkaItemReader<>(this.consumerProperties, "topic4b", 0, 1);
this.reader.setPollTimeout(Duration.ofSeconds(1));
this.reader.open(new ExecutionContext());

List<String> items = new ArrayList<>();
items.add(this.reader.read());
items.add(this.reader.read());
items.add(this.reader.read());
items.add(this.reader.read());
items.add(this.reader.read());
assertThat(items, containsInAnyOrder("val0", "val1", "val2", "val3", "val5"));
assertNull(this.reader.read());

this.reader.close();
futures = new ArrayList<>();
futures.add(this.template.send("topic4b", 0, null, "val4"));
futures.add(this.template.send("topic4b", 0, null, "val6"));
futures.add(this.template.send("topic4b", 1, null, "val7"));

for (ListenableFuture future : futures) {
future.get();
}

// topic4b-0: val0, val2, val4, val6
// ^
// |
// last committed offset = 1 (should restart from offset = 2)
// topic4b-1: val1, val3, val5, val7
// ^
// |
// last committed offset = 2 (should restart from offset = 3)

this.reader = new KafkaItemReader<>(this.consumerProperties, "topic4b", 0, 1);
this.reader.setPollTimeout(Duration.ofSeconds(1));
this.reader.open(new ExecutionContext());

items = new ArrayList<>();
items.add(this.reader.read());
items.add(this.reader.read());
items.add(this.reader.read());
assertThat(items, containsInAnyOrder("val4", "val6", "val7"));
String item = this.reader.read();
assertNull(item);

this.reader.close();
}

}