When using the MongoDB source connector with the Outbox Event Router SMT, tracing configuration properties appear to be ignored.

Connector configuration

 
"connector.class": "io.debezium.connector.mongodb.MongoDbConnector",
"mongodb.connection.string": "mongodb://mongo:27017/?replicaSet=rs0",
"topic.prefix": "test",
"database.include.list": "outbox",
"collection.include.list": "outbox.loans",
"mongodb.user": "mongo-cdc",
"mongodb.password": "password",
"value.converter": "org.apache.kafka.connect.json.JsonConverter",
"value.converter.schemas.enable": "false",
"transforms": "outbox",
"transforms.outbox.type": "io.debezium.connector.mongodb.transforms.outbox.MongoEventRouter",
"transforms.outbox.tracing.span.context.field": "propagation",
"transforms.outbox.tracing.with.context.field.only": "false",
"transforms.outbox.tracing.operation.name": "debezium-read",
"transforms.outbox.collection.field.event.key": "aggregateId",
"transforms.outbox.collection.field.event.id": "aggregateId",
"transforms.outbox.collection.field.event.payload": "eventPayload",
"transforms.outbox.collection.expand.json.payload": "true",
"transforms.outbox.collection.fields.additional.placement": "aggregateType:header:aggregate-type,aggregateId:header:aggregate-id,eventType:header:event-type",
"transforms.outbox.route.by.field": "topicName",
"transforms.outbox.route.topic.replacement": "${routedByValue}",
"errors.tolerance": "all",
"errors.log.enable": "true",
"errors.log.include.messages": "true"

• Debezium Version: 3.1.2
• MongoDB Version: 7.0.16 Community (Docker Compose)
• Connector Class: io.debezium.connector.mongodb.MongoDbConnector
• Transform: io.debezium.connector.mongodb.transforms.outbox.MongoEventRouter
• Expected Behavior: Tracing configuration is respected and traceparent is propagated correctly from the outbox event.
• Observed Behavior: A new traceparent is created for each event, and tracing context is not propagated as expected.

 Repro Steps:

1. Configure the MongoDB source connector with the MongoEventRouter SMT.

1. Enable OpenTelemetry tracing with the SMT configuration.

1. Emit an event from the MongoDB outbox collection with a traceparent field.

1. Observe that the emitted Kafka message has a new traceparent rather than propagating the original.

Diagnosis and Findings:

It seems that class:

    MongoEventRouter.java

in the method: 

    private <T> Map<String, T> convertConfigMap(Map<String, T> oldConfigMap)

Only retrieves a subset of keys (and doesn't convert the tracing keys):

 
Map<String, T> newConfigMap = new HashMap<>();
    for (String config : oldConfigMap.keySet()) {
        if (fieldNameConverter.containsKey(config))

{             newConfigMap.put(fieldNameConverter.get(config), oldConfigMap.get(config));         }

}
All other keys are dropped.

This config is then sent to 
EventRouterDelegate tha use the map (with missing configs) to setup the ActivateTracingSpan:
 
public void configure(Map<String, ?> configMap) {
if (ActivateTracingSpan.isOpenTelemetryAvailable()) {
   tracingSmt.configure(configMap);
   if(!configMap.containsKey(ActivateTracingSpan.TRACING_CONTEXT_FIELD_REQUIRED.name()))

{     tracingSmt.setRequireContextField(true);ActivateTracingSpan }

}
[...]
 
Basically can't configure custom values for:
 
tracing.span.context.field
tracing.with.context.field.only
tracing.operation.name