Default Headers

Silverback will add some headers to the produced messages. They may vary depending on the scenario. Here is the list of the default headers that may be sent.

The static classes DefaultMessageHeaders and KafkaMessageHeaders contain all default header names constants.

Default

Header	Name
MessageType	x-message-type
FailedAttempts	x-failed-attempts
ChunkIndex	x-chunk-index
ChunksCount	x-chunk-count
IsLastChunk	x-chunk-last
TraceId	traceparent
TraceState	tracestate
TraceBaggage	tracebaggage
ContentType	content-type
EncryptionKeyId	x-encryption-key-id
FailureReason	x-failure-reason

Kafka

Header	Name
Timestamp	x-kafka-message-timestamp
SourceConsumerGroupId	x-source-consumer-group-id
SourceTopic	x-source-topic
SourcePartition	x-source-partition
SourceOffset	x-source-offset
SourceTimestamp	x-source-timestamp
FirstChunkOffset	x-chunk-first-offset

MQTT

MQTT doesn't add any additional header to the produced messages. The constants in MqttMessageHeaders are used internally to map some envelope headers to the corresponding MQTT 5 properties (response topic and correlation data) and to set the dynamic destination topic.

Customizing Default Header Names

The default header names can be overridden using the WithCustomHeaderName configuration method.

services.AddSilverback()
    .WithConnectionToMessageBroker(options => options.AddKafka())
    .WithCustomHeaderName(DefaultMessageHeaders.ChunkIndex, "x-ch-idx")
    .WithCustomHeaderName(DefaultMessageHeaders.ChunksCount, "x-ch-cnt")
    .AddBrokerClientsConfigurator<MyClientsConfigurator>();