Configuration Options

A list of brokers to which the Kafka binder connects.

brokers allows hosts specified with or without port information (for example, host1,host2:port2). This sets the default port when no port is configured in the broker list.

Key/Value map of client properties (both producers and consumer) passed to all clients created by the binder. Due to the fact that these properties are used by both producers and consumers, usage should be restricted to common properties — for example, security settings. Unknown Kafka producer or consumer properties provided through this configuration are filtered out and not allowed to propagate. Properties here supersede any properties set in boot.

Key/Value map of arbitrary Kafka client consumer properties. In addition to support known Kafka consumer properties, unknown consumer properties are allowed here as well. Properties here supersede any properties set in boot and in the configuration property above.

The list of custom headers that are transported by the binder. Only required when communicating with older applications (⇐ 1.3.x) with a kafka-clients version < 0.11.0.0. Newer versions support headers natively.

The time to wait to get partition information, in seconds. Health reports as down if this timer expires.

The number of required acks on the broker. See the Kafka documentation for the producer acks property.

Effective only if autoCreateTopics or autoAddPartitions is set. The global minimum number of partitions that the binder configures on topics on which it produces or consumes data. It can be superseded by the partitionCount setting of the producer or by the value of instanceCount * concurrency settings of the producer (if either is larger).

Key/Value map of arbitrary Kafka client producer properties. In addition to support known Kafka producer properties, unknown producer properties are allowed here as well. Properties here supersede any properties set in boot and in the configuration property above.

The replication factor of auto-created topics if autoCreateTopics is active. Can be overridden on each binding.

If set to true, the binder creates new topics automatically. If set to false, the binder relies on the topics being already configured. In the latter case, if the topics do not exist, the binder fails to start.

If set to true, the binder creates new partitions if required. If set to false, the binder relies on the partition size of the topic being already configured. If the partition count of the target topic is smaller than the expected value, the binder fails to start.

Enables transactions in the binder. See transaction.id in the Kafka documentation and Transactions in the spring-kafka documentation. When transactions are enabled, individual producer properties are ignored and all producers use the spring.cloud.stream.kafka.binder.transaction.producer.* properties.

Global producer properties for producers in a transactional binder. See spring.cloud.stream.kafka.binder.transaction.transactionIdPrefix and Kafka Producer Properties and the general producer properties supported by all binders.

The bean name of a KafkaHeaderMapper used for mapping spring-messaging headers to and from Kafka headers. Use this, for example, if you wish to customize the trusted packages in a BinderHeaderMapper bean that uses JSON deserialization for the headers. If this custom BinderHeaderMapper bean is not made available to the binder using this property, then the binder will look for a header mapper bean with the name kafkaBinderHeaderMapper that is of type BinderHeaderMapper before falling back to a default BinderHeaderMapper created by the binder.

Flag to set the binder health as down, when any partitions on the topic, regardless of the consumer that is receiving data from it, is found without a leader.

When the truststore or keystore certificate location is given as a non-local file system resource (resources supported by org.springframework.core.io.Resource e.g. CLASSPATH, HTTP, etc.), the binder copies the resource from the path (which is convertible to org.springframework.core.io.Resource) to a location on the filesystem. This is true for both broker level certificates (ssl.truststore.location and ssl.keystore.location) and certificates intended for schema registry (schema.registry.ssl.truststore.location and schema.registry.ssl.keystore.location). Keep in mind that the truststore and keystore location paths must be provided under spring.cloud.stream.kafka.binder.configuration…​. For example, spring.cloud.stream.kafka.binder.configuration.ssl.truststore.location, spring.cloud.stream.kafka.binder.configuration.schema.registry.ssl.truststore.location, etc. The file will be copied to the location specified as the value for this property which must be an existing directory on the filesystem that is writable by the process running the application. If this value is not set and the certificate file is a non-local file system resource, then it will be copied to System’s temp directory as returned by System.getProperty("java.io.tmpdir"). This is also true, if this value is present, but the directory cannot be found on the filesystem or is not writable.

When set to true, the offset lag metric of each consumer topic is computed whenever the metric is accessed. When set to false only the periodically calculated offset lag is used.

The interval in which the offset lag for each consumer topic is computed. This value is used whenever metrics.defaultOffsetLagMetricsEnabled is disabled or its computation is taking too long.

Enable Micrometer observation registry on all the bindings in this binder.

KafkaHealthIndicator metadata consumer group.id. This consumer is used by the HealthIndicator to query the metadata about the topics in use.

Since version 2.1.1, this property is deprecated in favor of topic.properties, and support for it will be removed in a future version.

Since version 2.1.1, this property is deprecated in favor of topic.replicas-assignment, and support for it will be removed in a future version.

Since version 2.1.1, this property is deprecated in favor of topic.replication-factor, and support for it will be removed in a future version.

When true, topic partitions is automatically rebalanced between the members of a consumer group. When false, each consumer is assigned a fixed set of partitions based on spring.cloud.stream.instanceCount and spring.cloud.stream.instanceIndex. This requires both the spring.cloud.stream.instanceCount and spring.cloud.stream.instanceIndex properties to be set appropriately on each launched instance. The value of the spring.cloud.stream.instanceCount property must typically be greater than 1 in this case.

When autoCommitOffset is true, this setting dictates whether to commit the offset after each record is processed. By default, offsets are committed after all records in the batch of records returned by consumer.poll() have been processed. The number of records returned by a poll can be controlled with the max.poll.records Kafka property, which is set through the consumer configuration property. Setting this to true may cause a degradation in performance, but doing so reduces the likelihood of redelivered records when a failure occurs. Also, see the binder requiredAcks property, which also affects the performance of committing offsets. This property is deprecated as of 3.1 in favor of using ackMode. If the ackMode is not set and batch mode is not enabled, RECORD ackMode will be used.

Starting with version 3.1, this property is deprecated. See ackMode for more details on alternatives. Whether to autocommit offsets when a message has been processed. If set to false, a header with the key kafka_acknowledgment of the type org.springframework.kafka.support.Acknowledgment header is present in the inbound message. Applications may use this header for acknowledging messages. See the examples section for details. When this property is set to false, Kafka binder sets the ack mode to org.springframework.kafka.listener.AbstractMessageListenerContainer.AckMode.MANUAL and the application is responsible for acknowledging records. Also see ackEachRecord.

Specify the container ack mode. This is based on the AckMode enumeration defined in Spring Kafka. If ackEachRecord property is set to true and consumer is not in batch mode, then this will use the ack mode of RECORD, otherwise, use the provided ack mode using this property.

In pollable consumers, if set to true, it always auto commits on error. If not set (the default) or false, it will not auto commit in pollable consumers. Note that this property is only applicable for pollable consumers.

Whether to reset offsets on the consumer to the value provided by startOffset. Must be false if a KafkaBindingRebalanceListener is provided; see rebalance listener See reset-offsets for more information about this property.

The starting offset for new groups. Allowed values: earliest and latest. If the consumer group is set explicitly for the consumer 'binding' (through spring.cloud.stream.bindings.<channelName>.group), 'startOffset' is set to earliest. Otherwise, it is set to latest for the anonymous consumer group. See reset-offsets for more information about this property.

When set to true, it enables DLQ behavior for the consumer. By default, messages that result in errors are forwarded to a topic named error.<destination>.<group>. The DLQ topic name can be configurable by setting the dlqName property or by defining a @Bean of type DlqDestinationResolver. This provides an alternative option to the more common Kafka replay scenario for the case when the number of errors is relatively small and replaying the entire original topic may be too cumbersome. See kafka dlq processing for more information. Starting with version 2.0, messages sent to the DLQ topic are enhanced with the following headers: x-original-topic, x-exception-message, and x-exception-stacktrace as byte[]. By default, a failed record is sent to the same partition number in the DLQ topic as the original record. See dlq partition selection for how to change that behavior. Not allowed when destinationIsPattern is true.

When enableDlq is true, and this property is not set, a dead letter topic with the same number of partitions as the primary topic(s) is created. Usually, dead-letter records are sent to the same partition in the dead-letter topic as the original record. This behavior can be changed; see dlq partition selection. If this property is set to 1 and there is no DqlPartitionFunction bean, all dead-letter records will be written to partition 0. If this property is greater than 1, you MUST provide a DlqPartitionFunction bean. Note that the actual partition count is affected by the binder’s minPartitionCount property.

Map with a key/value pair containing generic Kafka consumer properties. In addition to having Kafka consumer properties, other configuration properties can be passed here. For example some properties needed by the application such as spring.cloud.stream.kafka.bindings.input.consumer.configuration.foo=bar. The bootstrap.servers property cannot be set here; use multi-binder support if you need to connect to multiple clusters.

The name of the DLQ topic to receive the error messages.

Using this, DLQ-specific producer properties can be set. All the properties available through kafka producer properties can be set through this property. When native decoding is enabled on the consumer (i.e., useNativeDecoding: true) , the application must provide corresponding key/value serializers for DLQ. This must be provided in the form of dlqProducerProperties.configuration.key.serializer and dlqProducerProperties.configuration.value.serializer.

Indicates which standard headers are populated by the inbound channel adapter. Allowed values: none, id, timestamp, or both. Useful if using native deserialization and the first component to receive a message needs an id (such as an aggregator that is configured to use a JDBC message store).

The name of a bean that implements RecordMessageConverter. Used in the inbound channel adapter to replace the default MessagingMessageConverter.

The interval, in milliseconds, between events indicating that no messages have recently been received. Use an ApplicationListener<ListenerContainerIdleEvent> to receive these events. See pause-resume for a usage example.

When true, the destination is treated as a regular expression Pattern used to match topic names by the broker. When true, topics are not provisioned, and enableDlq is not allowed, because the binder does not know the topic names during the provisioning phase. Note, the time taken to detect new topics that match the pattern is controlled by the consumer property metadata.max.age.ms, which (at the time of writing) defaults to 300,000ms (5 minutes). This can be configured using the configuration property above.

A Map of Kafka topic properties used when provisioning new topics — for example, spring.cloud.stream.kafka.bindings.input.consumer.topic.properties.message.format.version=0.9.0.0

A Map<Integer, List<Integer>> of replica assignments, with the key being the partition and the value being the assignments. Used when provisioning new topics. See the NewTopic Javadocs in the kafka-clients jar.

The replication factor to use when provisioning topics. Overrides the binder-wide setting. Ignored if replicas-assignments is present.

Timeout used for polling in pollable consumers.

Bean name of a KafkaAwareTransactionManager used to override the binder’s transaction manager for this binding. Usually needed if you want to synchronize another transaction with the Kafka transaction, using the ChainedKafkaTransactionManaager. To achieve exactly once consumption and production of records, the consumer and producer bindings must all be configured with the same transaction manager.

When using a transactional binder, the offset of a recovered record (e.g. when retries are exhausted and the record is sent to a dead letter topic) will be committed via a new transaction, by default. Setting this property to false suppresses committing the offset of recovered record.

CommonErrorHandler bean name to use per consumer binding. When present, this user provided CommonErrorHandler takes precedence over any other error handlers defined by the binder. This is a handy way to express error handlers, if the application does not want to use a ListenerContainerCustomizer and then check the destination/group combination to set an error handler.

Since version 2.1.1, this property is deprecated in favor of topic.properties, and support for it will be removed in a future version.

Since version 2.1.1, this property is deprecated in favor of topic.replicas-assignment, and support for it will be removed in a future version.

Since version 2.1.1, this property is deprecated in favor of topic.replication-factor, and support for it will be removed in a future version.

Upper limit, in bytes, of how much data the Kafka producer attempts to batch before sending.

Whether the producer is synchronous.

A SpEL expression evaluated against the outgoing message used to evaluate the time to wait for ack when synchronous publish is enabled — for example, headers['mySendTimeout']. The value of the timeout is in milliseconds. With versions before 3.0, the payload could not be used unless native encoding was being used because, by the time this expression was evaluated, the payload was already in the form of a byte[]. Now, the expression is evaluated before the payload is converted.

How long the producer waits to allow more messages to accumulate in the same batch before sending the messages. (Normally, the producer does not wait at all and simply sends all the messages that accumulated while the previous send was in progress.) A non-zero value may increase throughput at the expense of latency.

A SpEL expression evaluated against the outgoing message used to populate the key of the produced Kafka message — for example, headers['myKey']. With versions before 3.0, the payload could not be used unless native encoding was being used because, by the time this expression was evaluated, the payload was already in the form of a byte[]. Now, the expression is evaluated before the payload is converted. In the case of a regular processor (Function<String, String> or Function<Message<?>, Message<?>), if the produced key needs to be same as the incoming key from the topic, this property can be set as below. spring.cloud.stream.kafka.bindings.<output-binding-name>.producer.messageKeyExpression: headers['kafka_receivedMessageKey'] There is an important caveat to keep in mind for reactive functions. In that case, it is up to the application to manually copy the headers from the incoming messages to outbound messages. You can set the header, e.g. myKey and use headers['myKey'] as suggested above or, for convenience, simply set the KafkaHeaders.MESSAGE_KEY header, and you do not need to set this property at all.

A comma-delimited list of simple patterns to match Spring messaging headers to be mapped to the Kafka Headers in the ProducerRecord. Patterns can begin or end with the wildcard character (asterisk). Patterns can be negated by prefixing with !. Matching stops after the first match (positive or negative). For example !ask,as* will pass ash but not ask. id and timestamp are never mapped.

Map with a key/value pair containing generic Kafka producer properties. The bootstrap.servers property cannot be set here; use multi-binder support if you need to connect to multiple clusters.

A Map of Kafka topic properties used when provisioning new topics — for example, spring.cloud.stream.kafka.bindings.output.producer.topic.properties.message.format.version=0.9.0.0

A Map<Integer, List<Integer>> of replica assignments, with the key being the partition and the value being the assignments. Used when provisioning new topics. See the NewTopic Javadocs in the kafka-clients jar.

The replication factor to use when provisioning topics. Overrides the binder-wide setting. Ignored if replicas-assignments is present.

Set to true to override the default binding destination (topic name) with the value of the KafkaHeaders.TOPIC message header in the outbound message. If the header is not present, the default binding destination is used.

The bean name of a MessageChannel to which successful send results should be sent; the bean must exist in the application context. The message sent to the channel is the sent message (after conversion, if any) with an additional header KafkaHeaders.RECORD_METADATA. The header contains a RecordMetadata object provided by the Kafka client; it includes the partition and offset where the record was written in the topic.

Set the compression.type producer property. Supported values are none, gzip, snappy, lz4 and zstd. If you override the kafka-clients jar to 2.1.0 (or later), as discussed in the Spring for Apache Kafka documentation, and wish to use zstd compression, use spring.cloud.stream.kafka.bindings.<binding-name>.producer.configuration.compression.type=zstd.

Bean name of a KafkaAwareTransactionManager used to override the binder’s transaction manager for this binding. Usually needed if you want to synchronize another transaction with the Kafka transaction, using the ChainedKafkaTransactionManaager. To achieve exactly once consumption and production of records, the consumer and producer bindings must all be configured with the same transaction manager.

Timeout in number of seconds to wait for when closing the producer.

Normally, all output bindings associated with a transactional binder will publish in a new transaction, if one is not already in process. This property allows you to override that behavior. If set to true, records published to this output binding will not be run in a transaction, unless one is already in process.