Filter

The following provides usage information for the Confluent SMT io.confluent.connect.transforms.Filter.

Description

Include or drop records that match the filter.condition predicate.

The filter.condition is a predicate specifying JsonPath that is applied to each record processed, and when this predicate successfully matches the record is either included (when filter.type=include) or excluded (when filter.type=exclude).

The missing.or.null.behavior property defines how the transform behaves when a record does not have the field(s) used in the filter condition predicate. By default, the behavior is set to fail. However, the behavior can also be set to include or exclude the record that is missing the predicate’s field(s).

Use the transformation type designed for the record key (io.confluent.connect.transforms.Filter$Key) or value (io.confluent.connect.transforms.Filter$Value).

Installation

This transformation is developed by Confluent and does not ship by default with Kafka or Confluent Platform. You can install this transformation using the Confluent Hub Client:

confluent-hub install confluentinc/connect-transforms:latest

Examples

The configuration snippets below shows how to use and configure the Filter SMT.

The filter.condition is a predicate specifying JSON path. For more information on the JsonPath format, see JsonPath.

filterExample1 below defines the configuration for including records satisfying the filter condition. The filter.condition predicate specified in the record value is satisfied when the nested field 'author' in field 'book' is equal to either 'Tolstoy' or 'Dostoevsky'. The fail behavior is configured to throw an exception and fail the connector task when the record does not have the field(s) used in the filter condition.

transforms=filterExample1
# Use the 'io.confluent.connect.transforms.Filter$Value' as the source (record 'value') on which
# 'filter.condition' shall be applied.
transforms.filterExample1.type=io.confluent.connect.transforms.Filter$Value
transforms.filterExample1.filter.condition=$.book[?(@.author == "Tolstoy" || @author == "Dostoevsky")]
# Use 'include' to pass through all records that match the predicate.
transforms.filterExample1.filter.type=include
# Use the 'fail' behavior to throw an exception and fail the connector task when the record does
# not have the field(s) used in the 'filter.condition'.
transforms.filterExample1.missing.or.null.behavior=fail

filterExample2 below defines the configuration for excluding records satisfying the filter condition. The filter condition is applied to record key. The example uses the field timestamp and the nested field epoch. The include behavior is configured to pass the record through when the record does not have the field(s) used in the filter condition.

transforms=filterExample2
# Use the 'io.confluent.connect.transforms.Filter$Key' as the source (record 'key') on which
# 'filter.condition' shall be applied.
transforms.filterExample2.type=io.confluent.connect.transforms.Filter$Key
transforms.filterExample2.filter.condition=$.timestamp[?(@.epoch == "1594152325" || @epoch == "1594152326")]
# Use 'exclude' to drop all records that match the predicate.
transforms.filterExample2.filter.type=exclude
# Use the 'include' behavior to pass the record through when the record does not have the field(s)
# used in the 'filter.condition'.
transforms.filterExample2.missing.or.null.behavior=include

Properties

Name Description Type Default Valid Values Importance
filter.condition Specifies the criteria used to match records to be included or excluded by this transformation. Use JSON Path predicate notation defined in: https://github.com/json-path/JsonPath. string     high
filter.type Specifies the action to perform with records that match the filter.condition predicate. Use include to pass through all records that match the predicate and drop all records that do not satisfy the predicate, or use exclude to drop all records that match the predicate. string   [include, exclude] high
missing.or.null.behavior Specifies the behavior when the record does not have the field(s) used in the filter.condition. Use fail to throw an exception and fail the connector task, include to pass the record through, or exclude to drop the record. string fail [fail, include, exclude] medium