How can I create many kafka topics during spring-boot application start up? - spring

Question

I have this configuration:
#Configuration
public class KafkaTopicConfig {
private final TopicProperties topics;
public KafkaTopicConfig(TopicProperties topics) {
this.topics = topics;
}
#Bean
public NewTopic newTopicImportCharge() {
TopicProperties.Topic topic = topics.getTopicNameByType(MessageType.IMPORT_CHARGES.name());
return new NewTopic(topic.getTopicName(), topic.getNumPartitions(), topic.getReplicationFactor());
}
#Bean
public NewTopic newTopicImportPayment() {
TopicProperties.Topic topic = topics.getTopicNameByType(MessageType.IMPORT_PAYMENTS.name());
return new NewTopic(topic.getTopicName(), topic.getNumPartitions(), topic.getReplicationFactor());
}
#Bean
public NewTopic newTopicImportCatalog() {
TopicProperties.Topic topic = topics.getTopicNameByType(MessageType.IMPORT_CATALOGS.name());
return new NewTopic(topic.getTopicName(), topic.getNumPartitions(), topic.getReplicationFactor());
}
}
I can add 10 differents topics to TopicProperties. And I don't want create each similar bean manually. Does some way exist for create all topic in spring-kafka or only spring?

Answer 1

Use an admin client directly; you can get a pre-built properties map from Boot's KafkaAdmin.
#SpringBootApplication
public class So55336461Application {
public static void main(String[] args) {
SpringApplication.run(So55336461Application.class, args);
}
#Bean
public ApplicationRunner runner(KafkaAdmin kafkaAdmin) {
return args -> {
AdminClient admin = AdminClient.create(kafkaAdmin.getConfigurationProperties());
List<NewTopic> topics = new ArrayList<>();
// build list
admin.createTopics(topics).all().get();
};
}
}
EDIT
To check if they already exist, or if the partitions need to be increased, the KafkaAdmin has this logic...
private void addTopicsIfNeeded(AdminClient adminClient, Collection<NewTopic> topics) {
if (topics.size() > 0) {
Map<String, NewTopic> topicNameToTopic = new HashMap<>();
topics.forEach(t -> topicNameToTopic.compute(t.name(), (k, v) -> t));
DescribeTopicsResult topicInfo = adminClient
.describeTopics(topics.stream()
.map(NewTopic::name)
.collect(Collectors.toList()));
List<NewTopic> topicsToAdd = new ArrayList<>();
Map<String, NewPartitions> topicsToModify = checkPartitions(topicNameToTopic, topicInfo, topicsToAdd);
if (topicsToAdd.size() > 0) {
addTopics(adminClient, topicsToAdd);
}
if (topicsToModify.size() > 0) {
modifyTopics(adminClient, topicsToModify);
}
}
}
private Map<String, NewPartitions> checkPartitions(Map<String, NewTopic> topicNameToTopic,
DescribeTopicsResult topicInfo, List<NewTopic> topicsToAdd) {
Map<String, NewPartitions> topicsToModify = new HashMap<>();
topicInfo.values().forEach((n, f) -> {
NewTopic topic = topicNameToTopic.get(n);
try {
TopicDescription topicDescription = f.get(this.operationTimeout, TimeUnit.SECONDS);
if (topic.numPartitions() < topicDescription.partitions().size()) {
if (LOGGER.isInfoEnabled()) {
LOGGER.info(String.format(
"Topic '%s' exists but has a different partition count: %d not %d", n,
topicDescription.partitions().size(), topic.numPartitions()));
}
}
else if (topic.numPartitions() > topicDescription.partitions().size()) {
if (LOGGER.isInfoEnabled()) {
LOGGER.info(String.format(
"Topic '%s' exists but has a different partition count: %d not %d, increasing "
+ "if the broker supports it", n,
topicDescription.partitions().size(), topic.numPartitions()));
}
topicsToModify.put(n, NewPartitions.increaseTo(topic.numPartitions()));
}
}
catch (#SuppressWarnings("unused") InterruptedException e) {
Thread.currentThread().interrupt();
}
catch (TimeoutException e) {
throw new KafkaException("Timed out waiting to get existing topics", e);
}
catch (#SuppressWarnings("unused") ExecutionException e) {
topicsToAdd.add(topic);
}
});
return topicsToModify;
}

Answer 2

Currently we can just use KafkaAdmin.NewTopics
Spring Doc