Kafka Bridge Configuration Reference
The Kafka Broker Bridge forwards WAMP events to Kafka topics, using the same Mops expression language as the API Gateway for mapping between them. It only produces to Kafka — there is no consumer side that turns Kafka messages back into WAMP events.
Enabling the bridge
Enables or disables the Kafka Broker Bridge.
Path to the Broker Bridge's JSON specification file, which declares the actual subscriptions and their Kafka mappings — see the Broker Bridge Specification Object for its structure.
Client connection
Each client is named ($name) and configured independently; a deployment forwarding to more than one Kafka cluster defines one client block per cluster.
The Kafka broker endpoints for this client, written as an Erlang term: a list of {Host, Port} tuples, e.g. [{"127.0.0.1",9092}]. Configuration generation fails when the value does not parse as an Erlang term. Unset, the client has no endpoints.
Whether the client starts a producer for a topic automatically the first time an event is published to it, rather than requiring the producer to be started explicitly beforehand.
Whether the client's metadata requests can cause the broker to create a missing topic. With on, the broker's own auto.create.topics.enable setting decides. With off, the default, the client sends no metadata request that can create a topic, whatever the broker configuration says.
Number of times the client retries its socket connection when fetching topic metadata from the Kafka cluster, before giving up.
Delay before retrying to establish a new connection to the Kafka partition leader after a connection attempt fails.
How long to wait between attempts to restart the Kafka client process when it crashes.
Receive buffer size for the client's TCP socket to the Kafka broker, passed through to the underlying socket option. Leave unset to use the OS default.
Send buffer size for the client's TCP socket to the Kafka broker, passed through to the underlying socket option. Leave unset to use the OS default.
Producer behaviour
How many acknowledgements the Kafka broker waits for from the clustered replicas before it acknowledges the producer.
0- the broker will not send any response (this is the only case where the broker will not reply to a request)1- The leader will wait the data is written to the local log before sending a response-1- The broker will block until the message is committed by all in sync replicas before acknowledging
How long to wait before restarting a partition's producer process after it crashes — the per-partition analogue of restart_delay_seconds above.
How long to wait before restarting a topic's producer process after it crashes — the per-topic analogue of restart_delay_seconds above.
Topic mapping
A mapping of a short name to a Kafka topic. The broker_bridge.config_file specification references this name (e.g. broker_bridge.kafka.topics.important_events = "com.myapp.events.important" lets the spec's Mops expressions read {{kafka.topics.important_events}} rather than hard-coding the Kafka topic string).