PublishKafka_2_6

Description:

Sends the contents of a FlowFile as a message to Apache Kafka using the Kafka 2.5 Producer API.The messages to send may be individual FlowFiles or may be delimited, using a user-specified delimiter, such as a new-line. The complementary NiFi processor for fetching messages is ConsumeKafka_2_6.

Additional Details...

Tags:

Apache, Kafka, Put, Send, Message, PubSub, 2.5

Properties:

In the list below, the names of required properties appear in bold. Any other properties (not in bold) are considered optional. The table also indicates any default values, whether a property supports the NiFi Expression Language, and whether a property is considered "sensitive", meaning that its value will be encrypted. Before entering a value in a sensitive property, ensure that the nifi.properties file has an entry for the property nifi.sensitive.props.key.

NameDefault ValueAllowable ValuesDescription
Kafka Brokerslocalhost:9092A comma-separated list of known Kafka Brokers in the format <host>:<port>
Supports Expression Language: true (will be evaluated using variable registry only)
Security ProtocolPLAINTEXT
  • PLAINTEXT PLAINTEXT
  • SSL SSL
  • SASL_PLAINTEXT SASL_PLAINTEXT
  • SASL_SSL SASL_SSL
Protocol used to communicate with brokers. Corresponds to Kafka's 'security.protocol' property.
SASL MechanismGSSAPI
  • GSSAPI The mechanism for authentication via Kerberos. The principal and keytab must be provided to the processor by using a Keytab Credential service, or by specifying the properties directly in the processor.
  • PLAIN The mechanism for authentication via username and password. The username and password properties must be populated when using this mechanism.
  • SCRAM-SHA-256 The Salted Challenge Response Authentication Mechanism using SHA-256. The username and password properties must be set when using this mechanism.
  • SCRAM-SHA-512 The Salted Challenge Response Authentication Mechanism using SHA-512. The username and password properties must be set when using this mechanism.
The SASL mechanism to use for authentication. Corresponds to Kafka's 'sasl.mechanism' property.
Kerberos Service NameThe service name that matches the primary name of the Kafka server configured in the broker JAAS file.This can be defined either in Kafka's JAAS config or in Kafka's config. Corresponds to Kafka's 'security.protocol' property.It is ignored unless one of the SASL options of the <Security Protocol> are selected.
Supports Expression Language: true (will be evaluated using variable registry only)
Kerberos Credentials ServiceController Service API:
KerberosCredentialsService
Implementation: KeytabCredentialsService
Specifies the Kerberos Credentials Controller Service that should be used for authenticating with Kerberos
Kerberos PrincipalThe Kerberos principal that will be used to connect to brokers. If not set, it is expected to set a JAAS configuration file in the JVM properties defined in the bootstrap.conf file. This principal will be set into 'sasl.jaas.config' Kafka's property.
Supports Expression Language: true (will be evaluated using variable registry only)
Kerberos KeytabThe Kerberos keytab that will be used to connect to brokers. If not set, it is expected to set a JAAS configuration file in the JVM properties defined in the bootstrap.conf file. This principal will be set into 'sasl.jaas.config' Kafka's property.

This property requires exactly one file to be provided..

Supports Expression Language: true (will be evaluated using variable registry only)
UsernameThe username when the SASL Mechanism is PLAIN or SCRAM-SHA-256/SCRAM-SHA-512
Supports Expression Language: true (will be evaluated using variable registry only)
PasswordThe password for the given username when the SASL Mechanism is PLAIN or SCRAM-SHA-256/SCRAM-SHA-512
Sensitive Property: true
Supports Expression Language: true (will be evaluated using variable registry only)
Token Authfalse
  • true
  • false
When SASL Mechanism is SCRAM-SHA-256 or SCRAM-SHA-512, this property indicates if token authentication should be used.
SSL Context ServiceController Service API:
SSLContextService
Implementations: StandardSSLContextService
StandardRestrictedSSLContextService
Specifies the SSL Context Service to use for communicating with Kafka.
Topic NameThe name of the Kafka Topic to publish to.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Delivery Guarantee0
  • Best Effort FlowFile will be routed to success after successfully writing the content to a Kafka node, without waiting for a response. This provides the best performance but may result in data loss.
  • Guarantee Single Node Delivery FlowFile will be routed to success if the message is received by a single Kafka node, whether or not it is replicated. This is faster than <Guarantee Replicated Delivery> but can result in data loss if a Kafka node crashes
  • Guarantee Replicated Delivery FlowFile will be routed to failure unless the message is replicated to the appropriate number of Kafka Nodes according to the Topic configuration
Specifies the requirement for guaranteeing that a message is sent to Kafka. Corresponds to Kafka's 'acks' property.
Failure StrategyRoute to Failure
  • Route to Failure When unable to publish a FlowFile to Kafka, the FlowFile will be routed to the 'failure' relationship.
  • Rollback When unable to publish a FlowFile to Kafka, the FlowFile will be placed back on the top of its queue so that it will be the next FlowFile tried again. For dataflows where ordering of FlowFiles is important, this strategy can be used along with ensuring that the each processor in the dataflow uses only a single Concurrent Task.
Dictates how the processor handles a FlowFile if it is unable to publish the data to Kafka
Use Transactionstrue
  • true
  • false
Specifies whether or not NiFi should provide Transactional guarantees when communicating with Kafka. If there is a problem sending data to Kafka, and this property is set to false, then the messages that have already been sent to Kafka will continue on and be delivered to consumers. If this is set to true, then the Kafka transaction will be rolled back so that those messages are not available to consumers. Setting this to true requires that the <Delivery Guarantee> property be set to "Guarantee Replicated Delivery."
Transactional Id PrefixWhen Use Transaction is set to true, KafkaProducer config 'transactional.id' will be a generated UUID and will be prefixed with this string.
Supports Expression Language: true (will be evaluated using variable registry only)
Attributes to Send as Headers (Regex)A Regular Expression that is matched against all FlowFile attribute names. Any attribute whose name matches the regex will be added to the Kafka messages as a Header. If not specified, no FlowFile attributes will be added as headers.
Message Header EncodingUTF-8For any attribute that is added as a message header, as configured via the <Attributes to Send as Headers> property, this property indicates the Character Encoding to use for serializing the headers.
Kafka KeyThe Key to use for the Message. If not specified, the flow file attribute 'kafka.key' is used as the message key, if it is present.Beware that setting Kafka key and demarcating at the same time may potentially lead to many Kafka messages with the same key.Normally this is not a problem as Kafka does not enforce or assume message and key uniqueness. Still, setting the demarcator and Kafka key at the same time poses a risk of data loss on Kafka. During a topic compaction on Kafka, messages will be deduplicated based on this key.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Key Attribute Encodingutf-8
  • UTF-8 Encoded The key is interpreted as a UTF-8 Encoded string.
  • Hex Encoded The key is interpreted as arbitrary binary data that is encoded using hexadecimal characters with uppercase letters.
FlowFiles that are emitted have an attribute named 'kafka.key'. This property dictates how the value of the attribute should be encoded.
Message DemarcatorSpecifies the string (interpreted as UTF-8) to use for demarcating multiple messages within a single FlowFile. If not specified, the entire content of the FlowFile will be used as a single message. If specified, the contents of the FlowFile will be split on this delimiter and each section sent as a separate Kafka message. To enter special character such as 'new line' use CTRL+Enter or Shift+Enter, depending on your OS.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Max Request Size1 MBThe maximum size of a request in bytes. Corresponds to Kafka's 'max.request.size' property and defaults to 1 MB (1048576).
Acknowledgment Wait Time5 secsAfter sending a message to Kafka, this indicates the amount of time that we are willing to wait for a response from Kafka. If Kafka does not acknowledge the message within this time period, the FlowFile will be routed to 'failure'.
Max Metadata Wait Time5 secThe amount of time publisher will wait to obtain metadata or wait for the buffer to flush during the 'send' call before failing the entire 'send' call. Corresponds to Kafka's 'max.block.ms' property
Supports Expression Language: true (will be evaluated using variable registry only)
Partitioner classorg.apache.kafka.clients.producer.internals.DefaultPartitioner
  • RoundRobinPartitioner Messages will be assigned partitions in a round-robin fashion, sending the first message to Partition 1, the next Partition to Partition 2, and so on, wrapping as necessary.
  • DefaultPartitioner Messages will be assigned to random partitions.
  • Expression Language Partitioner Interprets the <Partition> property as Expression Language that will be evaluated against each FlowFile. This Expression will be evaluated once against the FlowFile, so all Records in a given FlowFile will go to the same partition.
Specifies which class to use to compute a partition id for a message. Corresponds to Kafka's 'partitioner.class' property.
PartitionSpecifies which Partition Records will go to.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Compression Typenone
  • none
  • gzip
  • snappy
  • lz4
This parameter allows you to specify the compression codec for all data generated by this producer.

Dynamic Properties:

Dynamic Properties allow the user to specify both the name and value of a property.

NameValueDescription
The name of a Kafka configuration property.The value of a given Kafka configuration property.These properties will be added on the Kafka configuration after loading any provided configuration properties. In the event a dynamic property represents a property that was already set, its value will be ignored and WARN message logged. For the list of available Kafka properties please refer to: http://kafka.apache.org/documentation.html#configuration.
Supports Expression Language: true (will be evaluated using variable registry only)

Relationships:

NameDescription
successFlowFiles for which all content was sent to Kafka.
failureAny FlowFile that cannot be sent to Kafka will be routed to this Relationship

Reads Attributes:

None specified.

Writes Attributes:

NameDescription
msg.countThe number of messages that were sent to Kafka for this FlowFile. This attribute is added only to FlowFiles that are routed to success. If the <Message Demarcator> Property is not set, this will always be 1, but if the Property is set, it may be greater than 1.

State management:

This component does not store state.

Restricted:

This component is not restricted.

Input requirement:

This component requires an incoming relationship.

System Resource Considerations:

None specified.