Kafka Connect ReplaceField SMT Usage Reference for Confluent Platform

The ReplaceField SMT (org.apache.kafka.connect.transforms.ReplaceField) filters or renames fields within an Apache Kafka® record’s Struct or Map.

Description

Filter or rename 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).

For the Confluent version that also supports nested fields, see ReplaceField (Confluent).

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 will be included in the resulting Struct or Map.	list	“”	Comma-separated list of fields to include.	medium
`replace.null.with.default`	Specifies whether to replace null fields with their defined default values. When set to `true`, the default value is applied. Otherwise, the field remains null.	boolean	`true`	`true` or `false`	medium

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"}

Predicates

Configure transformations with predicates to ensure they process only records that satisfy a particular condition. You can also use predicates in a transformation chain with the Kafka Connect Filter (Kafka) SMT Usage Reference for Confluent Platform to conditionally filter specific records. For more information, see Predicates.