A type: custom rule carries a check written in the native syntax of a specific quality engine. You name the engine with engine and provide the engine-specific definition under implementation. Custom rules let you use capabilities of an engine that the portable library and SQL rules don’t cover.
Custom rules are consumed by the matching engine — typically via the corresponding exporter — rather than being compiled to portable SQL.
schema:
- name: events
properties:
- name: event_type
logicalType: string
quality:
- type: custom
engine: dqx
implementation:
criticality: error
check:
function: is_in_list
arguments:
allowed:
- click
- view
- purchase
Export these to a DQX check file with datacontract export dqx.
schema:
- name: orders
quality:
- type: custom
engine: soda
implementation: |
checks for orders:
- row_count > 10
Export to a SodaCL file with datacontract export sodacl.
:::warning
Raw SodaCL custom checks (type: custom, engine: soda) are no longer executed by datacontract test since soda-core was removed; such a rule is reported as a warning. Migrate it to a SQL rule (type: sql) to keep it executable, or keep it as a custom rule purely for the SodaCL export.
:::
The same pattern applies to other engines (for example Great Expectations). Provide engine and an implementation understood by that engine, and use the matching exporter to generate its native artifact.
