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Kafka

The Kafka input plugin allows subscribing to one or more Kafka topics to collect messages from an Apache Kafka service. This plugin uses the official librdkafka C library (built-in dependency).

Configuration Parameters

Key
Description
default
brokers
Single or multiple list of Kafka Brokers, e.g: 192.168.1.3:9092, 192.168.1.4:9092.
topics
Single entry or list of topics separated by comma (,) that Fluent Bit will subscribe to.
client_id
Client id passed to librdkafka.
group_id
Group id passed to librdkafka.
fluent-bit
poll_ms
Kafka brokers polling interval in milliseconds.
500
rdkafka.{property}
{property} can be any librdkafka properties

Getting Started

In order to subscribe/collect messages from Apache Kafka, you can run the plugin from the command line or through the configuration file:

Command Line

The kafka plugin can read parameters through the -p argument (property), e.g:
$ fluent-bit -i kafka -o stdout -p brokers=192.168.1.3:9092 -p topics=some-topic

Configuration File

In your main configuration file append the following Input & Output sections:
[INPUT]
Name kafka
Brokers 192.168.1.3:9092
Topics some-topic
poll_ms 100
[OUTPUT]
Name stdout

Example of using kafka input/output plugins

The fluent-bit source repository contains a full example of using fluent-bit to process kafka records:
[INPUT]
Name kafka
brokers kafka-broker:9092
topics fb-source
poll_ms 100
[FILTER]
Name lua
Match *
script kafka.lua
call modify_kafka_message
[OUTPUT]
Name kafka
brokers kafka-broker:9092
topics fb-sink
The above will connect to the broker listening on kafka-broker:9092 and subscribe to the fb-source topic, polling for new messages every 100 milliseconds.
Every message received is then processed with kafka.lua and sent back to the fb-sink topic of the same broker.
The example can be executed locally with make start in the examples/kafka_filter directory (docker/compose is used).
Last modified 8d ago