Configuring event streams

The event streaming plugin for Apache Kafka is configured using command line options.

Ensure a Kafka system is available to receive streams from Hyperledger Besu.

Multiple topics are created for each event stream in the format <stream_prefix><domain_type>, where the domain types are:

• block
• transaction
• smart-contract
• node
• log

<stream_prefix> is defined using --plugin-kafka-stream.

Configuring a Kafka Event Stream

Configure a Kafka event stream in the command line by enabling the plugin and setting the appropriate options.

Example

besu --plugin-kafka-enabled --plugin-kafka-stream=my-besu-stream --plugin-kafka-url=127.0.0.1:9090 --plugin-kafka-producer-config-override-enabled --plugin-kafka-producer-property=sasl.mechanism=PLAIN

The command line specifies:

• Enable the Kafka plugin using the --plugin-kafka-enabled option.
• Prefix to identify the stream in Kafka using the --plugin-kafka-stream option.
• URL endpoint of the Kafka stream using the --plugin-kafka-url option.
• Override Kafka Producer configuration properties using the --plugin-kafka-producer-config-override-enabled option.
• Kafka Producer configuration property using the --plugin-kafka-producer-property option. If multiple properties are required, the --plugin-kafka-producer-property option can be specified multiple times.

Note

If --plugin-kafka-url is not specified, the plugin attempts to connect to a local Kafka broker at 127.0.0.1:9092.

Filtering smart contract event logs

You can configure event streaming plugins to filter event logs from specified smart contracts. To create the filter, use the following CLI options:

• plugin-kafka-log-filter-addresses
• plugin-kafka-log-filter-topics

To display the filtered events in a more readable format, create a schema file to decode the events. To specify the schema file location, use the --plugin-kafka-log-schema-file option.