Camel Spring Boot Starter for kafka

Spring Boot Auto-Configuration

When using kafka with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-kafka-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 98 options, which are listed below.

Name Description Default Type

camel.component.kafka.additional-properties

Sets additional properties for either kafka consumer or kafka producer in case they can’t be set directly on the camel configurations (e.g: new Kafka properties that are not reflected yet in Camel configurations), the properties have to be prefixed with additionalProperties.. E.g: additionalProperties.transactional.id=12345&additionalProperties.schema.registry.url=\http://localhost:8811/avro

Map

camel.component.kafka.allow-manual-commit

Whether to allow doing manual commits via KafkaManualCommit. If this option is enabled then an instance of KafkaManualCommit is stored on the Exchange message header, which allows end users to access this API and perform manual offset commits via the Kafka consumer.

false

Boolean

camel.component.kafka.auto-commit-enable

If true, periodically commit to ZooKeeper the offset of messages already fetched by the consumer. This committed offset will be used when the process fails as the position from which the new consumer will begin.

true

Boolean

camel.component.kafka.auto-commit-interval-ms

The frequency in ms that the consumer offsets are committed to zookeeper.

5000

Integer

camel.component.kafka.auto-commit-on-stop

Whether to perform an explicit auto commit when the consumer stops to ensure the broker has a commit from the last consumed message. This requires the option autoCommitEnable is turned on. The possible values are: sync, async, or none. And sync is the default value.

sync

String

camel.component.kafka.auto-offset-reset

What to do when there is no initial offset in ZooKeeper or if an offset is out of range: earliest : automatically reset the offset to the earliest offset latest : automatically reset the offset to the latest offset fail: throw exception to the consumer

latest

String

camel.component.kafka.basic-property-binding

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

Boolean

camel.component.kafka.break-on-first-error

This options controls what happens when a consumer is processing an exchange and it fails. If the option is false then the consumer continues to the next message and processes it. If the option is true then the consumer breaks out, and will seek back to offset of the message that caused a failure, and then re-attempt to process this message. However this can lead to endless processing of the same message if its bound to fail every time, eg a poison message. Therefore its recommended to deal with that for example by using Camel’s error handler.

false

Boolean

camel.component.kafka.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.kafka.brokers

URL of the Kafka brokers to use. The format is host1:port1,host2:port2, and the list can be a subset of brokers or a VIP pointing to a subset of brokers. This option is known as bootstrap.servers in the Kafka documentation.

String

camel.component.kafka.buffer-memory-size

The total bytes of memory the producer can use to buffer records waiting to be sent to the server. If records are sent faster than they can be delivered to the server the producer will either block or throw an exception based on the preference specified by block.on.buffer.full.This setting should correspond roughly to the total memory the producer will use, but is not a hard bound since not all memory the producer uses is used for buffering. Some additional memory will be used for compression (if compression is enabled) as well as for maintaining in-flight requests.

33554432

Integer

camel.component.kafka.check-crcs

Automatically check the CRC32 of the records consumed. This ensures no on-the-wire or on-disk corruption to the messages occurred. This check adds some overhead, so it may be disabled in cases seeking extreme performance.

true

Boolean

camel.component.kafka.client-id

The client id is a user-specified string sent in each request to help trace calls. It should logically identify the application making the request.

String

camel.component.kafka.compression-codec

This parameter allows you to specify the compression codec for all data generated by this producer. Valid values are none, gzip and snappy.

none

String

camel.component.kafka.configuration

Allows to pre-configure the Kafka component with common options that the endpoints will reuse. The option is a org.apache.camel.component.kafka.KafkaConfiguration type.

String

camel.component.kafka.connection-max-idle-ms

Close idle connections after the number of milliseconds specified by this config.

540000

Integer

camel.component.kafka.consumer-request-timeout-ms

The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.

40000

Integer

camel.component.kafka.consumer-streams

Number of concurrent consumers on the consumer

10

Integer

camel.component.kafka.consumers-count

The number of consumers that connect to kafka server

1

Integer

camel.component.kafka.enable-idempotence

If set to 'true' the producer will ensure that exactly one copy of each message is written in the stream. If 'false', producer retries may write duplicates of the retried message in the stream. If set to true this option will require max.in.flight.requests.per.connection to be set to 1 and retries cannot be zero and additionally acks must be set to 'all'.

false

Boolean

camel.component.kafka.enabled

Whether to enable auto configuration of the kafka component. This is enabled by default.

Boolean

camel.component.kafka.fetch-max-bytes

The maximum amount of data the server should return for a fetch request This is not an absolute maximum, if the first message in the first non-empty partition of the fetch is larger than this value, the message will still be returned to ensure that the consumer can make progress. The maximum message size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config). Note that the consumer performs multiple fetches in parallel.

52428800

Integer

camel.component.kafka.fetch-min-bytes

The minimum amount of data the server should return for a fetch request. If insufficient data is available the request will wait for that much data to accumulate before answering the request.

1

Integer

camel.component.kafka.fetch-wait-max-ms

The maximum amount of time the server will block before answering the fetch request if there isn’t sufficient data to immediately satisfy fetch.min.bytes

500

Integer

camel.component.kafka.group-id

A string that uniquely identifies the group of consumer processes to which this consumer belongs. By setting the same group id multiple processes indicate that they are all part of the same consumer group. This option is required for consumers.

String

camel.component.kafka.header-filter-strategy

To use a custom HeaderFilterStrategy to filter header to and from Camel message. The option is a org.apache.camel.spi.HeaderFilterStrategy type.

String

camel.component.kafka.heartbeat-interval-ms

The expected time between heartbeats to the consumer coordinator when using Kafka’s group management facilities. Heartbeats are used to ensure that the consumer’s session stays active and to facilitate rebalancing when new consumers join or leave the group. The value must be set lower than session.timeout.ms, but typically should be set no higher than 1/3 of that value. It can be adjusted even lower to control the expected time for normal rebalances.

3000

Integer

camel.component.kafka.interceptor-classes

Sets interceptors for producer or consumers. Producer interceptors have to be classes implementing org.apache.kafka.clients.producer.ProducerInterceptor Consumer interceptors have to be classes implementing org.apache.kafka.clients.consumer.ConsumerInterceptor Note that if you use Producer interceptor on a consumer it will throw a class cast exception in runtime

String

camel.component.kafka.kafka-header-deserializer

To use a custom KafkaHeaderDeserializer to deserialize kafka headers values. The option is a org.apache.camel.component.kafka.serde.KafkaHeaderDeserializer type.

String

camel.component.kafka.kafka-header-serializer

To use a custom KafkaHeaderSerializer to serialize kafka headers values. The option is a org.apache.camel.component.kafka.serde.KafkaHeaderSerializer type.

String

camel.component.kafka.kafka-manual-commit-factory

Factory to use for creating KafkaManualCommit instances. This allows to plugin a custom factory to create custom KafkaManualCommit instances in case special logic is needed when doing manual commits that deviates from the default implementation that comes out of the box. The option is a org.apache.camel.component.kafka.KafkaManualCommitFactory type.

String

camel.component.kafka.kerberos-before-relogin-min-time

Login thread sleep time between refresh attempts.

60000

Integer

camel.component.kafka.kerberos-init-cmd

Kerberos kinit command path. Default is /usr/bin/kinit

/usr/bin/kinit

String

camel.component.kafka.kerberos-principal-to-local-rules

A list of rules for mapping from principal names to short names (typically operating system usernames). The rules are evaluated in order and the first rule that matches a principal name is used to map it to a short name. Any later rules in the list are ignored. By default, principal names of the form {username}/{hostname}{REALM} are mapped to {username}. For more details on the format please see the security authorization and acls documentation.. Multiple values can be separated by comma

DEFAULT

String

camel.component.kafka.kerberos-renew-jitter

Percentage of random jitter added to the renewal time.

Double

camel.component.kafka.kerberos-renew-window-factor

Login thread will sleep until the specified window factor of time from last refresh to ticket’s expiry has been reached, at which time it will try to renew the ticket.

Double

camel.component.kafka.key

The record key (or null if no key is specified). If this option has been configured then it take precedence over header KafkaConstants#KEY

String

camel.component.kafka.key-deserializer

Deserializer class for key that implements the Deserializer interface.

org.apache.kafka.common.serialization.StringDeserializer

String

camel.component.kafka.key-serializer-class

The serializer class for keys (defaults to the same as for messages if nothing is given).

org.apache.kafka.common.serialization.StringSerializer

String

camel.component.kafka.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean

camel.component.kafka.linger-ms

The producer groups together any records that arrive in between request transmissions into a single batched request. Normally this occurs only under load when records arrive faster than they can be sent out. However in some circumstances the client may want to reduce the number of requests even under moderate load. This setting accomplishes this by adding a small amount of artificial delay that is, rather than immediately sending out a record the producer will wait for up to the given delay to allow other records to be sent so that the sends can be batched together. This can be thought of as analogous to Nagle’s algorithm in TCP. This setting gives the upper bound on the delay for batching: once we get batch.size worth of records for a partition it will be sent immediately regardless of this setting, however if we have fewer than this many bytes accumulated for this partition we will 'linger' for the specified time waiting for more records to show up. This setting defaults to 0 (i.e. no delay). Setting linger.ms=5, for example, would have the effect of reducing the number of requests sent but would add up to 5ms of latency to records sent in the absense of load.

0

Integer

camel.component.kafka.max-block-ms

The configuration controls how long sending to kafka will block. These methods can be blocked for multiple reasons. For e.g: buffer full, metadata unavailable.This configuration imposes maximum limit on the total time spent in fetching metadata, serialization of key and value, partitioning and allocation of buffer memory when doing a send(). In case of partitionsFor(), this configuration imposes a maximum time threshold on waiting for metadata

60000

Integer

camel.component.kafka.max-in-flight-request

The maximum number of unacknowledged requests the client will send on a single connection before blocking. Note that if this setting is set to be greater than 1 and there are failed sends, there is a risk of message re-ordering due to retries (i.e., if retries are enabled).

5

Integer

camel.component.kafka.max-partition-fetch-bytes

The maximum amount of data per-partition the server will return. The maximum total memory used for a request will be #partitions max.partition.fetch.bytes. This size must be at least as large as the maximum message size the server allows or else it is possible for the producer to send messages larger than the consumer can fetch. If that happens, the consumer can get stuck trying to fetch a large message on a certain partition.

1048576

Integer

camel.component.kafka.max-poll-interval-ms

The maximum delay between invocations of poll() when using consumer group management. This places an upper bound on the amount of time that the consumer can be idle before fetching more records. If poll() is not called before expiration of this timeout, then the consumer is considered failed and the group will rebalance in order to reassign the partitions to another member. The option is a java.lang.Long type.

String

camel.component.kafka.max-poll-records

The maximum number of records returned in a single call to poll()

500

Integer

camel.component.kafka.max-request-size

The maximum size of a request. This is also effectively a cap on the maximum record size. Note that the server has its own cap on record size which may be different from this. This setting will limit the number of record batches the producer will send in a single request to avoid sending huge requests.

1048576

Integer

camel.component.kafka.metadata-max-age-ms

The period of time in milliseconds after which we force a refresh of metadata even if we haven’t seen any partition leadership changes to proactively discover any new brokers or partitions.

300000

Integer

camel.component.kafka.metric-reporters

A list of classes to use as metrics reporters. Implementing the MetricReporter interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.

String

camel.component.kafka.metrics-sample-window-ms

The number of samples maintained to compute metrics.

30000

Integer

camel.component.kafka.no-of-metrics-sample

The number of samples maintained to compute metrics.

2

Integer

camel.component.kafka.offset-repository

The offset repository to use in order to locally store the offset of each partition of the topic. Defining one will disable the autocommit. The option is a org.apache.camel.spi.StateRepository<java.lang.String, java.lang.String> type.

String

camel.component.kafka.partition-assignor

The class name of the partition assignment strategy that the client will use to distribute partition ownership amongst consumer instances when group management is used

org.apache.kafka.clients.consumer.RangeAssignor

String

camel.component.kafka.partition-key

The partition to which the record will be sent (or null if no partition was specified). If this option has been configured then it take precedence over header KafkaConstants#PARTITION_KEY

Integer

camel.component.kafka.partitioner

The partitioner class for partitioning messages amongst sub-topics. The default partitioner is based on the hash of the key.

org.apache.kafka.clients.producer.internals.DefaultPartitioner

String

camel.component.kafka.poll-timeout-ms

The timeout used when polling the KafkaConsumer. The option is a java.lang.Long type.

5000

String

camel.component.kafka.producer-batch-size

The producer will attempt to batch records together into fewer requests whenever multiple records are being sent to the same partition. This helps performance on both the client and the server. This configuration controls the default batch size in bytes. No attempt will be made to batch records larger than this size.Requests sent to brokers will contain multiple batches, one for each partition with data available to be sent.A small batch size will make batching less common and may reduce throughput (a batch size of zero will disable batching entirely). A very large batch size may use memory a bit more wastefully as we will always allocate a buffer of the specified batch size in anticipation of additional records.

16384

Integer

camel.component.kafka.queue-buffering-max-messages

The maximum number of unsent messages that can be queued up the producer when using async mode before either the producer must be blocked or data must be dropped.

10000

Integer

camel.component.kafka.receive-buffer-bytes

The size of the TCP receive buffer (SO_RCVBUF) to use when reading data.

65536

Integer

camel.component.kafka.reconnect-backoff-max-ms

The maximum amount of time in milliseconds to wait when reconnecting to a broker that has repeatedly failed to connect. If provided, the backoff per host will increase exponentially for each consecutive connection failure, up to this maximum. After calculating the backoff increase, 20% random jitter is added to avoid connection storms.

1000

Integer

camel.component.kafka.reconnect-backoff-ms

The amount of time to wait before attempting to reconnect to a given host. This avoids repeatedly connecting to a host in a tight loop. This backoff applies to all requests sent by the consumer to the broker.

50

Integer

camel.component.kafka.record-metadata

Whether the producer should store the RecordMetadata results from sending to Kafka. The results are stored in a List containing the RecordMetadata metadata’s. The list is stored on a header with the key KafkaConstants#KAFKA_RECORDMETA

true

Boolean

camel.component.kafka.request-required-acks

The number of acknowledgments the producer requires the leader to have received before considering a request complete. This controls the durability of records that are sent. The following settings are common: acks=0 If set to zero then the producer will not wait for any acknowledgment from the server at all. The record will be immediately added to the socket buffer and considered sent. No guarantee can be made that the server has received the record in this case, and the retries configuration will not take effect (as the client won’t generally know of any failures). The offset given back for each record will always be set to -1. acks=1 This will mean the leader will write the record to its local log but will respond without awaiting full acknowledgement from all followers. In this case should the leader fail immediately after acknowledging the record but before the followers have replicated it then the record will be lost. acks=all This means the leader will wait for the full set of in-sync replicas to acknowledge the record. This guarantees that the record will not be lost as long as at least one in-sync replica remains alive. This is the strongest available guarantee.

1

String

camel.component.kafka.request-timeout-ms

The amount of time the broker will wait trying to meet the request.required.acks requirement before sending back an error to the client.

30000

Integer

camel.component.kafka.retries

Setting a value greater than zero will cause the client to resend any record whose send fails with a potentially transient error. Note that this retry is no different than if the client resent the record upon receiving the error. Allowing retries will potentially change the ordering of records because if two records are sent to a single partition, and the first fails and is retried but the second succeeds, then the second record may appear first.

0

Integer

camel.component.kafka.retry-backoff-ms

Before each retry, the producer refreshes the metadata of relevant topics to see if a new leader has been elected. Since leader election takes a bit of time, this property specifies the amount of time that the producer waits before refreshing the metadata.

100

Integer

camel.component.kafka.sasl-jaas-config

Expose the kafka sasl.jaas.config parameter Example: org.apache.kafka.common.security.plain.PlainLoginModule required username=USERNAME password=PASSWORD;

String

camel.component.kafka.sasl-kerberos-service-name

The Kerberos principal name that Kafka runs as. This can be defined either in Kafka’s JAAS config or in Kafka’s config.

String

camel.component.kafka.sasl-mechanism

The Simple Authentication and Security Layer (SASL) Mechanism used. For the valid values see http://www.iana.org/assignments/sasl-mechanisms/sasl-mechanisms.xhtml

GSSAPI

String

camel.component.kafka.schema-registry-u-r-l

URL of the Confluent Platform schema registry servers to use. The format is host1:port1,host2:port2. This is known as schema.registry.url in the Confluent Platform documentation. This option is only available in the Confluent Platform (not standard Apache Kafka)

String

camel.component.kafka.security-protocol

Protocol used to communicate with brokers. SASL_PLAINTEXT, PLAINTEXT and SSL are supported

PLAINTEXT

String

camel.component.kafka.seek-to

Set if KafkaConsumer will read from beginning or end on startup: beginning : read from beginning end : read from end This is replacing the earlier property seekToBeginning

String

camel.component.kafka.send-buffer-bytes

Socket write buffer size

131072

Integer

camel.component.kafka.serializer-class

The serializer class for messages.

org.apache.kafka.common.serialization.StringSerializer

String

camel.component.kafka.session-timeout-ms

The timeout used to detect failures when using Kafka’s group management facilities.

10000

Integer

camel.component.kafka.shutdown-timeout

Timeout in milli seconds to wait gracefully for the consumer or producer to shutdown and terminate its worker threads.

30000

Integer

camel.component.kafka.specific-avro-reader

This enables the use of a specific Avro reader for use with the Confluent Platform schema registry and the io.confluent.kafka.serializers.KafkaAvroDeserializer. This option is only available in the Confluent Platform (not standard Apache Kafka)

false

Boolean

camel.component.kafka.ssl-cipher-suites

A list of cipher suites. This is a named combination of authentication, encryption, MAC and key exchange algorithm used to negotiate the security settings for a network connection using TLS or SSL network protocol.By default all the available cipher suites are supported.

String

camel.component.kafka.ssl-context-parameters

SSL configuration using a Camel SSLContextParameters object. If configured it’s applied before the other SSL endpoint parameters. NOTE: Kafka only supports loading keystore from file locations, so prefix the location with file: in the KeyStoreParameters.resource option. The option is a org.apache.camel.support.jsse.SSLContextParameters type.

String

camel.component.kafka.ssl-enabled-protocols

The list of protocols enabled for SSL connections. TLSv1.2, TLSv1.1 and TLSv1 are enabled by default.

TLSv1.2

String

camel.component.kafka.ssl-endpoint-algorithm

The endpoint identification algorithm to validate server hostname using server certificate.

https

String

camel.component.kafka.ssl-key-password

The password of the private key in the key store file. This is optional for client.

String

camel.component.kafka.ssl-keymanager-algorithm

The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.

SunX509

String

camel.component.kafka.ssl-keystore-location

The location of the key store file. This is optional for client and can be used for two-way authentication for client.

String

camel.component.kafka.ssl-keystore-password

The store password for the key store file.This is optional for client and only needed if ssl.keystore.location is configured.

String

camel.component.kafka.ssl-keystore-type

The file format of the key store file. This is optional for client. Default value is JKS

JKS

String

camel.component.kafka.ssl-protocol

The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.

TLSv1.2

String

camel.component.kafka.ssl-provider

The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.

String

camel.component.kafka.ssl-trustmanager-algorithm

The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.

PKIX

String

camel.component.kafka.ssl-truststore-location

The location of the trust store file.

String

camel.component.kafka.ssl-truststore-password

The password for the trust store file.

String

camel.component.kafka.ssl-truststore-type

The file format of the trust store file. Default value is JKS.

JKS

String

camel.component.kafka.topic-is-pattern

Whether the topic is a pattern (regular expression). This can be used to subscribe to dynamic number of topics matching the pattern.

false

Boolean

camel.component.kafka.use-global-ssl-context-parameters

Enable usage of global SSL context parameters.

false

Boolean

camel.component.kafka.value-deserializer

Deserializer class for value that implements the Deserializer interface.

org.apache.kafka.common.serialization.StringDeserializer

String

camel.component.kafka.worker-pool

To use a custom worker pool for continue routing Exchange after kafka server has acknowledge the message that was sent to it from KafkaProducer using asynchronous non-blocking processing. If using this option then you must handle the lifecycle of the thread pool to shut the pool down when no longer needed. The option is a java.util.concurrent.ExecutorService type.

String

camel.component.kafka.worker-pool-core-size

Number of core threads for the worker pool for continue routing Exchange after kafka server has acknowledge the message that was sent to it from KafkaProducer using asynchronous non-blocking processing.

10

Integer

camel.component.kafka.worker-pool-max-size

Maximum number of threads for the worker pool for continue routing Exchange after kafka server has acknowledge the message that was sent to it from KafkaProducer using asynchronous non-blocking processing.

20

Integer