wiring.validation_results()

Validate a frame and yield the asset’s materialization and check results.

Usage

Source

wiring.validation_results(
    schema,
    frame,
    *,
    valid_key,
    quarantine_writer=None,
    check_granularity=None,
    schema_rules=None,
    max_failure_samples=None,
    statistics=None,
    row_sample=None
)

Parameters

frame: pl.DataFrame | pl.LazyFrame | None

The frame to validate, or None to skip.

valid_key: dg.AssetKey

The key the run materializes the valid rows under: the asset’s own key, such as context.asset_key. A key the asset does not have fails the step with DagsterInvariantViolationError on the first yield, and the asset writes nothing.

quarantine_writer: QuarantineWriter | None = None

The writer for the invalid rows, called at most once, with the frame quarantine_frame returns. With None, any invalid row fails the run with ValidationAbortError, and the asset writes nothing.

check_granularity: Granularity | None = None

Pass the value check_specs received, or the results name checks the asset does not declare. None uses DAGSTER_DATAFRAMELY_CHECK_GRANULARITY if set, else rule.

schema_rules: SchemaRules | None = None

Pass the value check_specs received, as for check_granularity. None uses DAGSTER_DATAFRAMELY_SCHEMA_RULES if set, else collapsed.

max_failure_samples: int | None = None

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

statistics: bool | None = None

Whether the materialization metadata has statistics of the written rows. None uses DAGSTER_DATAFRAMELY_STATISTICS if set, else True.

row_sample: int | None = None

The materialization metadata has at most this many valid rows, and this many invalid rows. None uses DAGSTER_DATAFRAMELY_ROW_SAMPLE if set, else 5.

Yields

The asset’s dg.MaterializeResult, if the run writes its table, then one dg.AssetCheckResult per check. On a skip, it yields only the check results, and every check passes. It writes the quarantine instead of yielding it.

Raises

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.

InvalidSettingError

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

DagsterInvariantViolationError

frame is neither a Polars frame nor None.

ColumnSchemaError

The frame’s columns or dtypes do not match the schema. It yields the column-schema check’s failing result first, and writes nothing.

ValidationAbortError

Rows failed validation and quarantine_writer is None, so the package writes nothing.

NoValidRowsError

Every row failed validation. It writes the quarantine, and not the asset’s table.