Therefore, by default the number of retry topics is the configured. The KafkaTemplate wraps a producer and provides convenience methods to send data to Kafka topics. The listener containers created for @KafkaListener annotations are not beans in the application context. The @KafkaListener annotation is used to designate a bean method as a listener for a listener container. You can get a reference to the bean from the application context, such as auto-wiring, to manage its registered containers. This header is a Headers object (or a List in the case of the batch converter), where the position in the list corresponds to the data position in the payload). For another technique to achieve similar results, but with the additional capability of sending different types to the same topic, see Delegating Serializer and Deserializer. Set observationEnabled to true on the KafkaTemplate and ContainerProperties to enable observation; this will disable Micrometer Timers because the timers will now be managed with each observation. Alternatively, you can get a reference to an individual container by using its id attribute. Starting with versions 2.1.11 and 2.2.1, property placeholders are resolved within @SendTo values. When using Spring for Apache Kafka in a Spring Boot application, the Apache Kafka dependency versions are determined by Spring Boots dependency management. By default, after ten failures, the failed record is logged (at the ERROR level). Spring for Apache Kafka When used with a DefaultBatchErrorHandler, you can use that header to determine which record the exception failed on and communicate to the error handler via a BatchListenerFailedException. A new RecoveringBatchErrorHandler is now provided. This can be the default (as provided in the constructor), or can be overridden by the KafkaTransactionManager (or KafkaTemplate for local transactions), if so configured. See Aggregating Multiple Replies for more information. Create a The following example shows how to do so: You must alias at least one of topics, topicPattern, or topicPartitions (and, usually, id or groupId unless you have specified a group.id in the consumer factory configuration). Starting with version 2.2.5, the DefaultAfterRollbackProcessor can be invoked in a new transaction (started after the failed transaction rolls back). See @KafkaListener @Payload Validation for more information. The default EOSMode is now BETA. See Testing Applications for more information. An additional property DelegatingByTopicSerialization.CASE_SENSITIVE (default true), when set to false makes the topic lookup case insensitive. The following example uses both @KafkaListener and @EventListener: Note that you can obtain the current positions when idle is detected by implementing ConsumerSeekAware in your listener. For convenience, we provide a test class-level annotation called @EmbeddedKafka to register the EmbeddedKafkaBroker bean. How often to check the state of the consumer threads for NonResponsiveConsumerEvent s. The JsonDeserializer now provides TypeReference-based constructors for better handling of target generic container types. The framework cannot know whether such a message has been processed or not. The following test case illustrates this mechanism. Use the second method if you need to provide type information for the return type, to assist the message converter. Before exiting, regardless of the outcome, the consumer is resumed. For example, to change the logging level to WARN you might add: Starting with version 1.1.4, Spring for Apache Kafka provides first-class support for Kafka Streams. The onlyLogRecordMetadata container property is now true by default. While you could pause a consumer in an idle container by using an event listener, in some cases, this was not thread-safe, since there is no guarantee that the event listener is invoked on the consumer thread. When incremental/cooperative rebalancing is configured, if offsets fail to commit with a non-fatal RebalanceInProgressException, the container will attempt to re-commit the offsets for the partitions that remain assigned to this instance after the rebalance is completed. Then, to use the template, you can invoke one of its methods. The methods from the underlying ProducerInterceptor implementations are invoked in the order as they were added to the CompositeProducerInterceptor. Get started with this digital assistant by texting When a message in the retry topic is not due for consumption, a KafkaBackOffException is thrown. This map should be ordered (e.g. See KAFKA-10683 for more information. There is a 30-second default maximum delay for the. Starting or stopping the registry will start or stop all the registered containers. You can now update the configuration map after the DefaultKafkaProducerFactory has been created. Other components that implement SmartLifecycle, to handle data from listeners, should be started in an earlier phase. This section describes how Spring for Apache Kafka supports transactions. You can also receive a list of ConsumerRecord objects, but it must be the only parameter (aside from optional Acknowledgment, when using manual commits and Consumer parameters) defined on the method. @SendTo("! Starting with versions 2.9.10, 3.0.8, this will be set to true unconditionally for such configurations. Starting with version 2.1.1, you can now set the client.id property for consumers created by the annotation. No replacements - use DefaultErrorHandler and throw an exception other than BatchListenerFailedException. KafkaHeaders.DLT_EXCEPTION_STACKTRACE: The Exception stack trace. Listeners can be configured to receive the entire batch of messages returned by the consumer.poll() operation, rather than one at a time. For POJO batch listeners, starting with version 2.8.6, the header is copied into each member of the batch and is also available as a single String parameter after conversion. This requires the brokers to be version 2.5 or later. If the delegate fails to deserialize the record content, the ErrorHandlingDeserializer returns a null value and a DeserializationException in a header that contains the cause and the raw bytes. New methods createOrModifyTopics and describeTopics have been added. If you go with this approach, then you need to set this producer interceptor on KafkaTemplate. Headers of type MimeType and MediaType are now mapped as simple strings in the RecordHeader value. You can add or remove exceptions to and from this list by overriding the configureNonBlockingRetries method in a @Configuration class that extends RetryTopicConfigurationSupport. To use it from a Spring application, the kafka-streams jar must be present on classpath. The changes will not affect existing producer instances; call reset() to close any existing producers so that new producers will be created using the new properties. The value of this header is an incrementing integer starting at 1. When using group management, onPartitionsAssigned is called when partitions are assigned. The KafkaEmbedded class and its KafkaRule interface have been deprecated in favor of the EmbeddedKafkaBroker and its JUnit 4 EmbeddedKafkaRule wrapper. Using the Same Broker(s) for Multiple Test Classes, 4.4.6. Notice that the send methods return a CompletableFuture. The pausing and resuming takes place respectively before and after the poll() similar to the pause() and resume() methods. Also you can choose what happens if DLT processing fails. The JsonDeserializer now removes any type information headers by default. Now a ListenerExecutionFailedException is always the argument (with the actual listener exception as the cause), which provides access to the containers group.id property. Subclass the recoverer and override createProducerRecord() - call super.createProducerRecord() and add more headers. Starting with version 1.1, you can configure @KafkaListener methods to receive the entire batch of consumer records received from the consumer poll. However, you can manually wire in those dependencies using the interceptor config() method. The attribute values can contain SpEL and/or property placeholders; the enhancer is called before any resolution is performed. Starting with version 2.0, if you use Springs test application context caching, you can also declare a EmbeddedKafkaBroker bean, so a single broker can be used across multiple test classes. to add a state store) and/or the Topology before the stream is created. Starting with version 2.9, for default configuration, the @EnableKafkaRetryTopic annotation should be used in a @Configuration annotated class. You can use this to set the initial position during initialization when group management is in use and Kafka assigns the partitions. An object of type FailedDeserializationInfo, which contains all the contextual information is provided to the function. You can inject the MessageConverter into a KafkaTemplate instance directly and by using AbstractKafkaListenerContainerFactory bean definition for the @KafkaListener.containerFactory() property. Spring Framework provides a number of BackOff implementations. The isPartitionPaused() method returns true if that partition has effectively been paused. Starting with version 2.8, if you construct the serializer or deserializer programmatically as shown in. You should also implement handleOtherException() - to handle exceptions that occur outside the scope of record processing (e.g. A new KafkaStreams is created on each start(). See Batch Listeners for more information. You can also use this method to associate this threads callback with the assigned partitions (see the example below). Listener performance can now be monitored using Micrometer Timer s. When a conversion error occurs, the payload is set to null and a deserialization exception is added to the record headers, similar to the ErrorHandlingDeserializer. So, before running tests with an embedded Kafka on random ports, we can set spring.embedded.kafka.brokers.property=spring.kafka.bootstrap-servers as a system property - and the EmbeddedKafkaBroker will use it to expose its broker addresses. For example, you may wish to invoke a DefaultErrorHandler for most exceptions, or a CommonContainerStoppingErrorHandler for others. The aggregate of partitions currently assigned to this containers child KafkaMessageListenerContainer s (explicitly or not). There are several ways to set the initial offset for a partition. To simplify using Kafka Streams from the Spring application context perspective and use the lifecycle management through a container, the Spring for Apache Kafka introduces StreamsBuilderFactoryBean. When using @KafkaListener with the DefaultKafkaHeaderMapper or SimpleKafkaHeaderMapper, it can be obtained by adding @Header(KafkaHeaders.DELIVERY_ATTEMPT) int delivery as a parameter to the listener method. Default false. This has an additional property called ackDiscarded, which indicates whether the adapter should acknowledge the discarded record. See Transactions with Batch Listeners for more information. You can also use @EventListener, introduced in Spring Framework 4.2. There is no limit to the number of groups or containers in a group. All you need is to declare a KafkaStreamsConfiguration bean named defaultKafkaStreamsConfig. WebGet the consumer properties that will be merged with the consumer properties provided by the consumer factory; properties here will supersede any with the same name (s) in The following example shows how to do so: Starting with version 2.5, you can now override the factorys ProducerConfig properties to create templates with different producer configurations from the same factory. Pausing and Resuming Listener Containers, 4.1.18. If there is no converter (either because Jackson is not present or it is explicitly set to null), the headers from the consumer record are provided unconverted in the KafkaHeaders.NATIVE_HEADERS header. By default the topics are autocreated with one partition and a replication factor of -1 (meaning use the broker default). With the batch converter, the converted headers are available in the KafkaHeaders.BATCH_CONVERTED_HEADERS as a List> where the map in a position of the list corresponds to the data position in the payload. Events related to consumer authentication and authorization. When repeatedly republishing a failed record, these headers can grow (and eventually cause publication to fail due to a RecordTooLargeException); this is especially true for the exception headers and particularly for the stack trace headers. See the javadocs for ContainerProperties.AssignmentCommitOption for more information about the available options. The following example shows how to do so: The following example shows how to set the idleEventInterval for a @KafkaListener: In each of these cases, an event is published once per minute while the container is idle. You can configure the handler with a custom recoverer (BiConsumer) and a BackOff that controls the delivery attempts and delays between each. See Using Methods to Determine Types for more information. You can also provide a custom implementation of Spring Retrys SleepingBackOffPolicy interface: You can set the global timeout for the retrying process. KafkaHeaders.DLT_KEY_EXCEPTION_STACKTRACE: The Exception stack trace (key deserialization errors only). To replace any BatchErrorHandler implementation, you should implement handleBatch() The logging level for logs pertaining to committing offsets. Further, you can explicitly configure the groupId on the annotation. The following example creates a set of mappings: If you use Spring Boot, you can provide these properties in the application.properties (or yaml) file. See Streams Configuration for more information. Pausing and Resuming Partitions on Listener Containers, 4.1.19. See Configuring Global Settings and Features for more information. The DefaultErrorHandler considers certain exceptions to be fatal, and retries are skipped for such exceptions; the recoverer is invoked on the first failure. When the container is paused, stop processing after the current record instead of after processing all the records from the previous poll; the remaining records are retained in memory and will be passed to the listener when the container is resumed. The transactional id is provided in case you wish to use a different MockProducer based on this value. The header mappers also convert to String when creating MessageHeaders from the consumer record and never map this header on an outbound record. Since version 2.7.3, Spring for Apache Kafka provides the ExponentialBackOffWithMaxRetries which is a subclass that receives the maxRetries property and automatically calculates the maxElapsedTime, which is a little more convenient. Although the Serializer and Deserializer API is quite simple and flexible from the low-level Kafka Consumer and Producer perspective, you might need more flexibility at the Spring Messaging level, when using either @KafkaListener or Spring Integrations Apache Kafka Support. For example the following interface can be defined as message payload type: Accessor methods will be used to lookup the property name as field in the received JSON document by default. To enable this feature, use a ProjectingMessageConverter configured with an appropriate delegate converter (used for outbound conversion and converting non-projection interfaces). This topic will be suffixed with the provided or default suffix, and will not have either the index or the delay values appended. Previously, this was not possible. There are now several techniques to customize which headers are added to the output record. The consumer can be paused before redelivery, by setting the sleep argument. This version requires the 3.0.0 kafka-clients. The timeout passed into Consumer.poll() (in milliseconds) when the container is in a paused state. Receiving such an event lets you stop the containers, thus waking the consumer so that it can stop. If retries are exhausted and recovery fails, seeks are performed as if retries are not exhausted. Jan 20, 2022 at 18:24 This interface is responsible for assigning partitions to consumers for its subscribed topics. New KafkaHeaders have been introduced regarding timestamp support. Since 2.9, the previous bean overriding approach for configuring components has been removed (without deprecation, due to the aforementioned experimental nature of the API). SeekUtils has been moved from the o.s.k.support package to o.s.k.listener. The record property in both observation contexts contains the ConsumerRecord or ProducerRecord respectively. This executor creates threads with names similar to -C-. Simplest Spring Kafka Producer and Consumer - DEV Community This version requires the 2.7.0 kafka-clients. A stand-alone (not Spring test context) broker will be created if the class annotated with @EmbeddedBroker is not also annotated (or meta annotated) with ExtendedWith(SpringExtension.class). The @EmbeddedKafka annotation now has the attribute ports to specify the port that populates the EmbeddedKafkaBroker. offset positive and toCurrent true - seek relative to the current position (fast forward). You can also set a timeout for the verification of the sender success with setWaitForSendResultTimeout. For the deserializer, the consumer property can be a Map where the key is the selector and the value is a Deserializer instance, a deserializer Class or the class name. ShouldRetryViaBothException.class would retry via blocking, and if all blocking retries fail would be forwarded to the next retry topic for another set of attempts. Such exceptions are logged by default at DEBUG level, but you can change this behavior by setting an error handler customizer in the ListenerContainerFactoryConfigurer in a @Configuration class. Starting with version 2.0, the @KafkaListener annotation has a new attribute: errorHandler. Starting with version 2.8.4, if you wish to add custom headers (in addition to the retry information headers added by the factory, you can add a headersFunction to the factory - factory.setHeadersFunction((rec, ex) { }). When using a POJO batch listener (e.g. To create a mapper for inbound mapping, use one of the static methods on the respective mapper: This will exclude all headers beginning with abc and include all others. It is impossible, therefore, to easily maintain retry state for a batch. By default, logging of topic offset commits is performed with the DEBUG logging level. The template in Using ReplyingKafkaTemplate is strictly for a single request/reply scenario. See Container Error Handlers and Migrating Custom Legacy Error Handler Implementations to CommonErrorHandler for more information. Setting the maxFailures property to a negative number causes infinite retries. This can be used to add headers within the stream processing; the header values are SpEL expressions; the root object of the expression evaluation has 3 properties: record - the org.apache.kafka.streams.processor.api.Record (key, value, timestamp, headers), context - the ProcessorContext, allowing access to the current record metadata. The execute method provides direct access to the underlying Producer. Spring Boot will automatically wire in its auto configured template (or any if a single instance is present). The framework provides the DeadLetterPublishingRecoverer, which publishes the failed message to another topic. The ConsumerStartingEvent, ConsumerStartingEvent, ConsumerFailedToStartEvent, ConsumerStoppedEvent, ConsumerRetryAuthSuccessfulEvent and ContainerStoppedEvent events have the following properties: All containers (whether a child or a parent) publish ContainerStoppedEvent. ToStringSerializer.ADD_TYPE_INFO_HEADERS (default true): You can set it to false to disable this feature on the ToStringSerializer (sets the addTypeInfo property). Several options are provided for committing offsets. Note that KafkaStreamsCustomizer overrides the options provided by StreamsBuilderFactoryBean. WebPriority Queue Support Overview RabbitMQ has priority queue implementation in the core as of version 3.5.0 . You can provide a custom executor by setting the consumerExecutor property of the containers ContainerProperties. Starting with version 2.6.7, in addition to detecting DeserializationException s, the template will call the replyErrorChecker function, if provided. Apache Kafka provides a mechanism to add interceptors to producers and consumers. At the time of writing, the lag will only be corrected if the consumer is configured with isolation.level=read_committed and max.poll.records is greater than 1. As you can see, you have to define several infrastructure beans when not using Spring Boot. Starting with version 2.2.4, any ListenerExecutionFailedException (thrown, for example, when an exception is detected in a @KafkaListener method) is enhanced with the groupId property. This event might signal that the configured task executor has insufficient threads to support the containers it is used in and their concurrency. The DLT handler method can also be provided through the RetryTopicConfigurationBuilder.dltHandlerMethod(String, String) method, passing as arguments the bean name and method name that should process the DLTs messages. ListenerContainerIdleEvent: published when no messages have been received in idleInterval (if configured). This "final" retry topic will be suffixed with the provided or default suffix, and will have either the index or the maxInterval value appended. When receiving a raw ConsumerRecord the integer is in a byte[4]. There are two mechanisms to add more headers. You can specify which exceptions you want to retry on and which not to. The property can also be a String of comma-delimited map entries, as shown below. The properties can be simple values, property placeholders, or SpEL expressions. You can now override the producer factorys transactionIdPrefix on the KafkaTemplate and KafkaTransactionManager. The following example combines all the topics we have covered in this chapter: The spring-kafka-test jar contains some useful utilities to assist with testing your applications. A new container property (missingTopicsFatal) has been added. WebGet Started! You cannot specify the group.id and client.id properties this way; they will be ignored; use the groupId and clientIdPrefix annotation properties for those. See Apache Kafka Streams Support and Configuration for more information. See Retrying Deserializer for more information. The ListenerContainerIdleEvent has the following properties: source: The listener container instance that published the event. See Configuring Global Settings and Features for more information. When you use Log Compaction, you can send and receive messages with null payloads to identify the deletion of a key. As ListenerContainerIdleEvent s are received, each individual child container in each container is stopped. Spring for Apache Kafka adds support in the following ways: KafkaTransactionManager: Used with normal Spring transaction support (@Transactional, TransactionTemplate etc). See Using ReplyingKafkaTemplate for more information. Starting with version 2.6.4, you can specify a comma-delimited list of partitions, or partition ranges: The range is inclusive; the example above will assign partitions 0, 1, 2, 3, 4, 5, 7, 10, 11, 12, 13, 14, 15. Implementations for native Micrometer metrics are provided. When using the embedded broker, it is generally best practice using a different topic for each test, to prevent cross-talk. Starting with version 2.2, you can now override the container factorys concurrency and autoStartup properties by using properties on the annotation itself. See Manually Committing Offsets for more information. The futures returned by this class are now CompletableFuture s instead of ListenableFuture s. You can configure the deserializer with the name of the parser method using ConsumerConfig properties: The properties must contain the fully qualified name of the class followed by the method name, separated by a period .. Please submit GitHub issues and/or pull requests for additional entries in that chapter. ConsumerRetryAuthSuccessfulEvent: published when authentication or authorization has been retried successfully. Since 2.7 you can use the setFailIfSendResultIsError method so that an exception is thrown when message publishing fails. You can also set groupId explicitly or set idIsGroup to false to restore the previous behavior of using the consumer factory group.id. There is now a mechanism to examine a reply and fail the future exceptionally if some condition exists. See Payload Conversion with Batch Listeners for more information. The KafkaTransactionManager and other support for transactions have been added. Mappings consist of a comma-delimited list of token:className pairs. By default, when the factory bean is stopped, the KafkaStreams.cleanUp() method is called. The CommonLoggingErrorHandler simply logs the exception; with a record listener, the remaining records from the previous poll are passed to the listener. See Non-Blocking Retries for more information. For example, container.setConcurrency(3) creates three KafkaMessageListenerContainer instances. You also can specify KafkaStreams.StateListener, Thread.UncaughtExceptionHandler, and StateRestoreListener options on the StreamsBuilderFactoryBean, which are delegated to the internal KafkaStreams instance. When using the default AfterRollbackProcessor with a record listener, seeks are performed so that the failed record will be redelivered. For record listeners, wWhen the AckMode is BATCH, or for batch listeners, the entire batch is replayed when the container is restarted. To enable this feature, simply add the listeners to your producer and consumer factories: The consumer/producer id passed to the listener is added to the meters tags with tag name spring.id. Following is an example using the same MyProducerInterceptor from above, but changed to not use the internal config property. Also see KafkaTemplate Transactional and non-Transactional Publishing. They are now simple strings for interoperability. These header names are used by the @KafkaListener infrastructure to route the reply. Starting with version 3.0, the @RetryableTopic annotation can be used as a meta-annotation on custom annotations; for example: You can also configure the non-blocking retry support by creating RetryTopicConfiguration beans in a @Configuration annotated class. For an existing group ID, the initial offset is the current offset for that group ID. When using transactions, the minimum broker version is 2.5. For example, with the @KafkaListener container factory, you can add DefaultErrorHandler as follows: For a record listener, this will retry a delivery up to 2 times (3 delivery attempts) with a back off of 1 second, instead of the default configuration (FixedBackOff(0L, 9)). Consumers and Producers are generally long-lived. The number of records before committing pending offsets when the ackMode is COUNT or COUNT_TIME. The KafkaTemplate instance is required for message forwarding. See Exception Classifier for more information. Now you can use the same factory for retryable and non-retryable topics. Overview Apache Kafka is a powerful, distributed, fault-tolerant stream processing system. Default no-op implementations are provided to avoid having to implement both methods if one is not required. Convenience methods have been added to AbstractConsumerSeekAware to make seeking easier. KafkaAdmin.NewTopics has been added to facilitate configuring multiple topics in a single bean. For five TopicPartitionOffset instances, two containers get two partitions, and the third gets one. The following example shows such a configuration: When you use a class-level @KafkaListener with multiple @KafkaHandler methods, some additional configuration is needed. When the method exits, the database transaction will commit followed by the Kafka transaction. This, together with an increased session.timeout.ms, can be used to reduce rebalance events, for example, when application instances are restarted. Kafka Starting with version 2.3.1, similar to the DefaultErrorHandler, the DefaultAfterRollbackProcessor considers certain exceptions to be fatal, and retries are skipped for such exceptions; the recoverer is invoked on the first failure.
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