build_rule_checks()

Return an asset check for each of the schema’s rules on asset, plus the column-schema check.

Usage

Source

build_rule_checks(
    schema,
    /,
    *,
    asset,
    name=None,
    partitions_def=None,
    check_granularity=None,
    max_failure_examples=None
)

The checks read the asset’s table through its own IO manager, as a pl.DataFrame, and write nothing.

Parameters

schema: type[dy.Schema]

The schema whose rules become checks.

asset: str | dg.AssetKey

The key of the asset whose table the checks read, which dd.asset did not build.

name: str | None = None

The name of the step that runs the checks. None uses the asset key’s Python identifier followed by __checks, because a name built from the schema would repeat for two assets that share it, and Dagster raises on two steps with one name.

partitions_def: dg.PartitionsDefinition | None = None

The asset’s partitions, so each run checks one partition. Dagster does not check that it matches the asset’s.

check_granularity: Granularity | None = None

How many checks report the schema’s rules: one per rule at rule, and at column one per column with rules plus one per schema-level rule. None uses DAGSTER_DATAFRAMELY_CHECK_GRANULARITY if set, else rule.

max_failure_examples: int | None = None

A rule’s check metadata has at most this many rows that failed it. None uses DAGSTER_DATAFRAMELY_MAX_FAILURE_EXAMPLES if set, else 5.

Returns

dg.AssetChecksDefinition

One definition with every check, which Dagster runs in one step. Pass it to dg.Definitions(asset_checks=[...]).

Raises

InvalidSettingError

A setting’s argument or environment variable has a value the setting does not allow.

ReservedColumnError

A column name is in the reserved dy_ namespace.

InvalidColumnNameError

A column name has a character Dagster does not allow in an asset check name.

CheckNameCollisionError

Two rules produce the same asset check name.

InvalidSeverityError

The schema declares a severity this package cannot read.

ColumnSchemaError

In a run, the table’s columns or dtypes do not match the schema.

Examples

import dagster_dataframely as dd
from dagster_dataframely.data import OrdersSchema

warehouse_checks = dd.build_rule_checks(OrdersSchema, asset="warehouse_orders")
[spec.name for spec in warehouse_checks.check_specs][:4]

['dy_schema__columns',
 'dy_rule__paid_orders_have_amount',
 'dy_rule__line_numbers_are_dense',
 'dy_rule__primary_key']