Kafka Connect Transformations - RegexRouter replacement topic names in lowercase - apache-kafka

Question

We are trying to setup a connector (Debezium) in Kafka Connect and transform all the topic names generated by this connector via regular expressions. The regex below is working and detects the patterns we want, but we also need to create all the topic names in lowercase.
We have tried to put this in the replacement expression as \L$1 but it is just printing and L in front of our topic names, for example LOutbound.Policy instead of outbound.policy
Does anybody know how to do this? Thanks in advance!
This is the connector curl command
curl -i -X PUT http://kafka-alpha-cp-kafka-connect:8083/connectors/kafka-bi-datacontract/config -H "Content-Type: application/json" -d '{
"name": "kafka-bi-datacontract",
"connector.class" : "io.debezium.connector.sqlserver.SqlServerConnector",
"database.hostname" : "ukdb3232123",
"database.server.name" : "ukdb3232123\\perf",
"database.port" : "12442",
"database.user" : "KafkaConnect-BI",
"database.password" : "*******",
"database.dbname" : "BeazleyIntelligenceDataContract",
"snapshot.lock.timeout.ms" : "10000000",
"table.whitelist" : "Outbound.Policy,Outbound.Section",
"database.history.kafka.bootstrap.servers" : "kafka-alpha-cp-kafka-headless:9092",
"database.history.kafka.topic": "schema-changes.bidatacontract",
"transforms": "dropTopicPrefix",
"transforms.dropTopicPrefix.type":"org.apache.kafka.connect.transforms.RegexRouter",
"transforms.dropTopicPrefix.regex":"^[^.]+.(.*)",
"transforms.dropTopicPrefix.replacement":"\\L$1"
}'

Answer 1

\L$1 or \\L$1 would be the same as L$1.
You would need to create/find your own transform for lowercasing.
Once you do, you can do something like this
"transforms": "dropTopicPrefix,lowertopic",
"transforms.dropTopicPrefix.type":"org.apache.kafka.connect.transforms.RegexRouter",
"transforms.dropTopicPrefix.regex":"^[^.]+.(.*)",
"transforms.dropTopicPrefix.replacement":"$1",
"transforms.lowerTopic.type":"com.example.foo.LowerCase$Topic",