Description and usage of PublishKafka_0_11 processor:

Sends the contents of a FlowFile as a message to Apache Kafka using the Kafka 0.11.x Producer API.The messages to send may be individual FlowFiles or may be delimited, using a user-specified delimiter, such as a new-line. Please note there are cases where the publisher can get into an indefinite stuck state. We are closely monitoring how this evolves in the Kafka community and will take advantage of those fixes as soon as we can. In the meantime it is possible to enter states where the only resolution will be to restart the JVM NiFi runs on. The complementary NiFi processor for fetching messages is ConsumeKafka_0_11.


Apache, Kafka, Put, Send, Message, PubSub, 0.11.x


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, and whether a property supports the NiFi Expression Language.


Default Value

Allowable Values


Kafka Brokers

localhost:9092 A comma-separated list of known Kafka Brokers in the format <host>:<port>

Supports Expression Language: true

Security Protocol

Protocol used to communicate with brokers. Corresponds to Kafka's 'security.protocol' property.
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. Corresponds to Kafka's 'security.protocol' property.It is ignored unless one of the SASL options of the <Security Protocol> are selected.
Kerberos Principal The 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.
Kerberos Keytab The 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.
SSL Context Service

Controller Service API: 



Specifies the SSL Context Service to use for communicating with Kafka.

Topic Name

The name of the Kafka Topic to publish to.

Supports Expression Language: true

Delivery Guarantee

0 * Best Effort
  * Guarantee Single Node Delivery
  * Guarantee Replicated Delivery 
Specifies the requirement for guaranteeing that a message is sent to Kafka. Corresponds to Kafka's 'acks' property.

Use Transactions

true * 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."
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 Encoding UTF-8 For 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 Key The 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 and we're not demarcating.

Supports Expression Language: true

Key Attribute Encoding

utf-8 * UTF-8 Encoded
* Hex Encoded 
FlowFiles that are emitted have an attribute named 'Kafka.key'. This property dictates how the value of the attribute should be encoded.
Message Demarcator Specifies 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

Max Request Size

1 MB The maximum size of a request in bytes. Corresponds to Kafka's 'max.request.size' property and defaults to 1 MB (1048576).

Acknowledgment Wait Time

5 secs After 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 Time

5 sec The 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 '' property

Supports Expression Language: true

Partitioner class org.apache.kafka.clients.producer.internals.DefaultPartitioner * RoundRobinPartitioner
* DefaultPartitioner 
Specifies which class to use to compute a partition id for a message. Corresponds to Kafka's 'partitioner.class' property.

Compression Type

none * 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.




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:





success FlowFiles for which all content was sent to Kafka.
failure Any FlowFile that cannot be sent to Kafka will be routed to this Relationship.

Reads Attributes:

None specified.

Writes Attributes:



msg.count The 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.


This component is not restricted.

Input requirement:

This component requires an incoming relationship.

How to configure?

This sample explains how to publish the content of the file as a message to Kafka consumer.



Step 1: Get the file content

Drag and drop the GetFile processor and specify the Input Directory and File Filter to fetch the content of the file.


Step 2: Send as a message

Drag and drop the PublishKafka_0_11 processor and specify the following properties.

Kafka Brokers: <host>:<port> where Kafka consumer is running

Topic Name: <Kafka topic name, where the message to be published>


After starting the processors, the content of the file will be published as a message to Kafka consumer.