We would like to list all Kafka topics via spring-kafka to get results similar to the kafka command:
bin/kafka-topics.sh --list --zookeeper localhost:2181
When running the getTopics() method in the service below, we get org.apache.kafka.common.errors.TimeoutException: Timeout expired while fetching topic metadata
Configuration:
#EnableKafka
#Configuration
public class KafkaConfig {
#Bean
public ConsumerFactory<String, String> consumerFactory() {
Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:2181");
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
StringDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
StringDeserializer.class);
return new DefaultKafkaConsumerFactory<>(props);
}
Service:
#Service
public class TopicServiceKafkaImpl implements TopicService {
#Autowired
private ConsumerFactory<String, String> consumerFactory;
#Override
public Set<String> getTopics() {
try (Consumer<String, String> consumer =
consumerFactory.createConsumer()) {
Map<String, List<PartitionInfo>> map = consumer.listTopics();
return map.keySet();
}
}
Kafka is up and running and we can send messages from our app to a topic succesfully.
You can list topics like this using Admin Client
Properties properties = new Properties();
properties.put(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
AdminClient adminClient = AdminClient.create(properties);
ListTopicsOptions listTopicsOptions = new ListTopicsOptions();
listTopicsOptions.listInternal(true);
System.out.println("topics:" + adminClient.listTopics(listTopicsOptions).names().get());
You are connecting to Zookeeper (2181) instead of Kafka (9092 by default).
The Java kafka clients no longer talk directly to ZK.
kafka-topics --list is a shell script that just is a wrapper around kafka.admin.TopicCommand class, where you can find the method you are looking for
Alternatively, you can also use the AdminClient#listTopics method
Related
There is a data stream application. It is necessary to connect and listen from several Kafka brokers (different ip-addresses, more than 2) and to write to the one.
Pls advise how to arrange multi-kafka connection?
Configuration class for a single kafka connection:
#Configuration
public class KafkaProducer {
#Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:29092");
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
return props;
}
#Bean
public ProducerFactory<String, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
#Bean
public KafkaTemplate<String, String> kafkaTemplate() {
return new KafkaTemplate<>(producerFactory());
}
}
It is expected several connections to be arranged and listened in the same time.
Bootstrap server config option accepts a CSV list for multiple brokers of one cluster. But you only need to provide multiple options for fault tolerance, as Kafka automatically returns all servers in the same cluster on first connection.
If you need to connect to distinct Kafka clusters, create a Bean with the different bootstrap address
We see some messages are lost in consuming messages from Kafka topic, especially during restarting of service when using the default properties
#Bean
public ConsumerFactory<String, String> consumerFactory()
{
// Creating a Map of string-object pairs
Map<String, Object> config = new HashMap<>();
// Adding the Configuration
config.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,
"127.0.0.1:9092");
config.put(ConsumerConfig.GROUP_ID_CONFIG,
"group_id");
config.put(
ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
StringDeserializer.class);
config.put(
ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
StringDeserializer.class);
return new DefaultKafkaConsumerFactory<>(config);
}
// Creating a Listener
public ConcurrentKafkaListenerContainerFactory
concurrentKafkaListenerContainerFactory()
{
ConcurrentKafkaListenerContainerFactory<
String, String> factory
= new ConcurrentKafkaListenerContainerFactory<>();
factory.setConsumerFactory(consumerFactory());
return factory;
}
}
From the documentation, it was mentioned the default value for ackMode is BATCH which states this
Commit the offset when all the records returned by the poll() have been processed
How does spring know that all the messages are processed is a sample example like in here ? and does it mean, when we restart the service offsets are committed and we haven't processed the messages leads to loosing of the messages
#KafkaListener(topics = "topicName", groupId = "foo")
public void listenGroupFoo(String message) {
System.out.println("Received Message in group foo: " + message);
}
I have an app using Spring Boot 2.5.2
We have a kafka consumer and it's running in some instance of applications.
Here is the Consumer Config
#Bean("KafkaListenerContainerFactory")
public ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory() {
ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
factory.setConsumerFactory(consumerFactory());
factory.setBatchListener(isBatchConsumer);
factory.getContainerProperties().setAckMode(ContainerProperties.AckMode.MANUAL_IMMEDIATE);
factory.getContainerProperties().setConsumerTaskExecutor(messageProcessorExecutor());
return factory;
}
#Bean
public ConsumerFactory<String, String> consumerFactory() {
Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, messagingAddress);
props.put(ConsumerConfig.MAX_POLL_RECORDS_CONFIG, maxBatch);
props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);
props.put(ConsumerConfig.DEFAULT_ISOLATION_LEVEL, IsolationLevel.READ_COMMITTED);
props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, sessionTimeoutKafkaConfig);
props.put(
ConsumerConfig.PARTITION_ASSIGNMENT_STRATEGY_CONFIG,
CooperativeStickyAssignor.class.getName());
return new DefaultKafkaConsumerFactory<>(props);
}
Here is my Consumer
#KafkaListener(topics = "${topic.mesage}", groupId = "#{'${groupid.ms}'}", properties = {
"key.deserializer=org.apache.kafka.common.serialization.StringDeserializer",
"value.deserializer=org.apache.kafka.common.serialization.StringDeserializer"}, concurrency = "${messaging.consumer.concurrent.thread}", containerFactory = "KafkaListenerContainerFactory")
public void consumerListener(String data, Acknowledgment acknowledgment, #Header(KafkaHeaders.RECEIVED_PARTITION_ID) Integer partitions,
#Header(KafkaHeaders.OFFSET) Long offsets) {
logger.info("MessagingConsumer partitions {} offsets {}", partitions, offsets);
acknowledgment.acknowledge();
logger.info("MessagingConsumer acknowledge: " + data);
...
When I redeploy my application, an error occur. I found a request has been duplicated consume.
In the first instance, we found 2 logs show that the message has been ack ("MessagingConsumer partitions 29 offsets 21204" and "MessagingConsumer acknowledge:") . But after sometime, the messsage has been consume again in second instance with same partition and offset. between that log of 2 instance, I found some "partitions revoked:" and "partitions assigned:".
But I cannot understand why if I has ack sucessfully , why the message still consume twice.
Could anyone help me?
I'm a newbie trying to make the communication work between two Spring Boot microservices using Confluent Cloud Apache Kafka.
When using Kafka on Confluent Cloud, I'm getting the following error on my consumer(ServiceB) after ServiceA publishes the message to the topic. However, when I login to my Confluent Cloud, I see that the message has been successfully published to the topic.
org.springframework.context.ApplicationContextException: Failed to start bean
'org.springframework.kafka.config.internalKafkaListenerEndpointRegistry'; nested exception is
java.lang.IllegalStateException: Topic(s) [topic-1] is/are not present and
missingTopicsFatal is true
I do not face this issue when I run Kafka on my local server. ServiceA is able to publish the message to the topic on my local Kafka server and ServiceB is successfully able to consume that message.
I have mentioned my local Kafka server configuration in application.properties(as commented out code)
Service A: PRODUCER
application.properties
app.topic=test-1
#Remote
ssl.endpoint.identification.algorithm=https
security.protocol=SASL_SSL
sasl.mechanism=PLAIN
request.timeout.ms=20000
bootstrap.servers=pkc-4kgmg.us-west-2.aws.confluent.cloud:9092
retry.backoff.ms=500
sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule
requiredusername="*******"
password="****"
#Local
#ssl.endpoint.identification.algorithm=https
#security.protocol=SASL_SSL
#sasl.mechanism=PLAIN
#request.timeout.ms=20000
#bootstrap.servers=localhost:9092
#retry.backoff.ms=500
#sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule
Sender.java
public class Sender {
#Autowired
private KafkaTemplate<String, String> kafkaTemplate;
#Value("${app.topic}")
private String topic;
public void send(String data){
Message<String> message = MessageBuilder
.withPayload(data)
.setHeader(KafkaHeaders.TOPIC, topic)
.build();
kafkaTemplate.send(message);
}
}
KafkaProducerConfig.java
#Configuration
#EnableKafka
public class KafkaProducerConfig {
#Value("${bootstrap.servers}")
private String bootstrapServers;
#Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
return props;
}
#Bean
public ProducerFactory<String, String> producerFactory() {
return new DefaultKafkaProducerFactory(producerConfigs());
}
#Bean
public KafkaTemplate<String, String> kafkaTemplate() {
return new KafkaTemplate(producerFactory());
}
}
Service B: CONSUMER
application.properties
app.topic=test-1
#Remote
ssl.endpoint.identification.algorithm=https
security.protocol=SASL_SSL
sasl.mechanism=PLAIN
request.timeout.ms=20000
bootstrap.servers=pkc-4kgmg.us-west-2.aws.confluent.cloud:9092
retry.backoff.ms=500
sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule
requiredusername="*******"
password="****"
#Local
#ssl.endpoint.identification.algorithm=https
#security.protocol=SASL_SSL
#sasl.mechanism=PLAIN
#request.timeout.ms=20000
#bootstrap.servers=localhost:9092
#retry.backoff.ms=500
#sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule
KafkaConsumerConfig.java
#Configuration
#EnableKafka
public class KafkaConsumerConfig {
#Value("${bootstrap.servers}")
private String bootstrapServers;
#Bean
public Map<String, Object> consumerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.GROUP_ID_CONFIG, "confluent_cli_consumer_040e5c14-0c18-4ae6-a10f-8c3ff69cbc1a"); // confluent cloud consumer group-id
props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
return props;
}
#Bean
public ConsumerFactory<String, String> consumerFactory() {
return new DefaultKafkaConsumerFactory(
consumerConfigs(),
new StringDeserializer(), new StringDeserializer());
}
#Bean(name = "kafkaListenerContainerFactory")
public ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory() {
ConcurrentKafkaListenerContainerFactory<String, String> factory =
new ConcurrentKafkaListenerContainerFactory();
factory.setConsumerFactory(consumerFactory());
return factory;
}
}
KafkaConsumer.java
#Service
public class KafkaConsumer {
private static final Logger LOG = LoggerFactory.getLogger(KafkaListener.class);
#Value("{app.topic}")
private String kafkaTopic;
#KafkaListener(topics = "${app.topic}", containerFactory = "kafkaListenerContainerFactory")
public void receive(#Payload String data) {
LOG.info("received data='{}'", data);
}
}
The username and password are part of the JAAS config, so put them on one line
sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required username="kafkaclient1" password="kafkaclient1-secret";
I would also suggest that you verify your property file is correctly loaded into the client
See the Boot documentation.
You can't just put arbitrary kafka properties directly in the application.properties file.
The properties supported by auto configuration are shown in appendix-application-properties.html. Note that, for the most part, these properties (hyphenated or camelCase) map directly to the Apache Kafka dotted properties. Refer to the Apache Kafka documentation for details.
The first few of these properties apply to all components (producers, consumers, admins, and streams) but can be specified at the component level if you wish to use different values. Apache Kafka designates properties with an importance of HIGH, MEDIUM, or LOW. Spring Boot auto-configuration supports all HIGH importance properties, some selected MEDIUM and LOW properties, and any properties that do not have a default value.
Only a subset of the properties supported by Kafka are available directly through the KafkaProperties class. If you wish to configure the producer or consumer with additional properties that are not directly supported, use the following properties:
spring.kafka.properties.prop.one=first
spring.kafka.admin.properties.prop.two=second
spring.kafka.consumer.properties.prop.three=third
spring.kafka.producer.properties.prop.four=fourth
spring.kafka.streams.properties.prop.five=fifth
This sets the common prop.one Kafka property to first (applies to producers, consumers and admins), the prop.two admin property to second, the prop.three consumer property to third, the prop.four producer property to fourth and the prop.five streams property to fifth.
...
#cricket_007's answer is correct. You need to embed the username and password (notably, the cluster API key and API secret) within the sasl.jaas.config property value.
You can double-check how Java clients should connect to Confluent Cloud via this official example here: https://github.com/confluentinc/examples/blob/5.3.1-post/clients/cloud/java/src/main/java/io/confluent/examples/clients/cloud
Thanks,
-- Ricardo
Java code to create a kafka consumer using spring integration java dsl
Use the below code to create a message driven adapter to connect to consume message from kafka
#Value("${spring.kafka.bootstrap-servers}")
private String bootstrapServers;
#Value("${spring.kafka.topic}")
private String springIntegrationKafkaTopic;
#Bean
public IntegrationFlow kafkaReader() throws Exception {
return IntegrationFlows
.from(Kafka.messageDrivenChannelAdapter(listener(),ListenerMode.record))
.channel("queureader")
.get();
}
#Bean
public KafkaMessageListenerContainer listener() {
return new KafkaMessageListenerContainer(consumerFactory(), new ContainerProperties(this.springIntegrationKafkaTopic));
}
#Bean
public ConsumerFactory consumerFactory() {
Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, this.bootstrapServers);
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.GROUP_ID_CONFIG, "kafkaListener");
return new DefaultKafkaConsumerFactory(props);
}
#ServiceActivator(inputChannel = "queureader")
public void Print(Message<?> msg) {
System.out.println(msg.getPayload().toString());
}
In application.properties
spring.kafka.bootstrap-servers = We need to mention the server name
-spring.kafka.topic= Name of the topic
You can mention any value for ConsumerConfig.GROUP_ID_CONFIG.