Kafka Connect ReplaceField SMT Usage Reference for Confluent Cloud

The org.apache.kafka.connect.transforms.ReplaceField Apache Kafka® Single Message Transform (SMT) filters or renames fields in a record’s Struct or Map.

Description

The ReplaceField SMT filters or renames fields within a Struct or Map.

Use the concrete transformation type designed for the record key (org.apache.kafka.connect.transforms.ReplaceField$Key) or value (org.apache.kafka.connect.transforms.ReplaceField$Value).

Examples

These examples show how to configure and use ReplaceField.

Drop a field

This configuration snippet shows how to use ReplaceField to exclude a field and remove it.

"transforms": "ReplaceField",
"transforms.ReplaceField.type": "org.apache.kafka.connect.transforms.ReplaceField$Value",
"transforms.ReplaceField.exclude": "c2"

This removes c2, transforming the original message as shown here:

{"c1":22,"c2":"foo"}

to this result:

{"c1":22}

Rename a field

This configuration snippet shows how to use ReplaceField with the renames property.

"transforms": "RenameField",
"transforms.RenameField.type": "org.apache.kafka.connect.transforms.ReplaceField$Value",
"transforms.RenameField.renames": "foo:c1,bar:c2"

This replaces the foo and bar field names with c1 and c2.

Before: {"foo":22,"bar":"baz"}

After: {"c1":22,"c2":"baz"}

Tip

For additional examples, see Replace Field for managed connectors.

Properties

Name	Description	Type	Default	Valid Values	Importance
`exclude`	Fields to exclude from the resulting Struct or Map. This takes precedence over the include list.	List	“”	Comma-separated list of fields to exclude.	Medium
`renames`	Field rename mappings.	List	“”	Comma-separated list of colon-delimited renaming pairs, for example `foo:bar,abc:xyz`.	Medium
`include`	Fields to include. If specified, only the named fields are included in the resulting Struct or Map.	List	“”	Comma-separated list of fields to include.	Medium

Predicates

Transformations can be configured with predicates so that the transformation is applied only to records which satisfy a condition. You can use predicates in a transformation chain and, when combined with the Kafka Connect Filter (Kafka) SMT Usage Reference for Confluent Cloud, predicates can conditionally filter out specific records. For details and examples, see Predicates.