Kafka Connect KeyToValue SMT Usage Reference for Confluent Cloud¶

The following provides usage information for the SMT com.clickhouse.kafka.connect.transforms.KeyToValue.

Description¶

The KeyToValue SMT converts Kafka message key into a value. It is particularly useful when you want to store a message’s key data directly within its value. By default, the key’s content is added to the value under a new field named _key with a String type.

To apply the KeyToValue SMT, add the following to your connector configuration:

"transforms": "KeyToValue",
"transforms.KeyToValue.type": "com.clickhouse.kafka.connect.transforms.KeyToValue",
"transforms.KeyToValue.fields": "<key-name>"

Replace the <field-name> with the message key you want to convert into a value.

Examples¶

The example below shows how to use KeyToValue SMT.

Consider a Kafka message with the following key and value:

Key:
```
123
```

Value (before SMT):

{
  "name": "John Doe",
  "email": "john.doe@example.com"
}

Adding the SMT to your Connector Configuration:

To apply the KeyToValue SMT, add the following to your connector configuration:

"transforms": "KeyToValue",
"transforms.KeyToValue.type": "com.clickhouse.kafka.connect.transforms.KeyToValue",
"transforms.KeyToValue.fields": "customer_id"

Value (after SMT):

After the KeyToValue SMT applies, the message value transforms as follows:

{
  "customer_id": 123,
  "name": "John Doe",
  "email": "john.doe@example.com"
}