from dagster import (
DagsterInvariantViolationError,
_check as check,
)
from pandas import DataFrame, Timestamp
from pandas.core.dtypes.common import (
is_bool_dtype,
is_float_dtype,
is_integer_dtype,
is_numeric_dtype,
is_string_dtype,
)
from dagster_pandas.constraints import (
CategoricalColumnConstraint,
ColumnDTypeFnConstraint,
ColumnDTypeInSetConstraint,
Constraint,
ConstraintViolationException,
DataFrameConstraint,
InRangeColumnConstraint,
NonNullableColumnConstraint,
UniqueColumnConstraint,
)
PANDAS_NUMERIC_TYPES = {"int64", "float"}
def _construct_keyword_constraints(non_nullable, unique, ignore_missing_vals):
non_nullable = check.bool_param(non_nullable, "exists")
unique = check.bool_param(unique, "unique")
ignore_missing_vals = check.bool_param(ignore_missing_vals, "ignore_missing_vals")
if non_nullable and ignore_missing_vals:
raise DagsterInvariantViolationError(
"PandasColumn cannot have a non-null constraint while also ignore missing values"
)
constraints = []
if non_nullable:
constraints.append(NonNullableColumnConstraint())
if unique:
constraints.append(UniqueColumnConstraint(ignore_missing_vals=ignore_missing_vals))
return constraints
[docs]class PandasColumn:
"""The main API for expressing column level schemas and constraints for your custom dataframe
types.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If th column exists, the validate function will validate the column. Defaults to True.
constraints (Optional[List[Constraint]]): List of constraint objects that indicate the
validation rules for the pandas column.
"""
def __init__(self, name, constraints=None, is_required=None):
self.name = check.str_param(name, "name")
self.is_required = check.opt_bool_param(is_required, "is_required", default=True)
self.constraints = check.opt_list_param(constraints, "constraints", of_type=Constraint)
def validate(self, dataframe):
if self.name not in dataframe.columns:
# Ignore validation if column is missing from dataframe and is not required
if self.is_required:
raise ConstraintViolationException(
f"Required column {self.name} not in dataframe with columns {dataframe.columns}"
)
else:
for constraint in self.constraints:
constraint.validate(dataframe, self.name)
@staticmethod
def exists(name, non_nullable=False, unique=False, ignore_missing_vals=False, is_required=None):
"""Simple constructor for PandasColumns that expresses existence constraints.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
non_nullable (Optional[bool]): If true, this column will enforce a constraint that all values in the column
ought to be non null values.
unique (Optional[bool]): If true, this column will enforce a uniqueness constraint on the column values.
ignore_missing_vals (Optional[bool]): A flag that is passed into most constraints. If true, the constraint will
only evaluate non-null data. Ignore_missing_vals and non_nullable cannot both be True.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If the column exists the validate function will validate the column. Default to True.
"""
return PandasColumn(
name=check.str_param(name, "name"),
constraints=_construct_keyword_constraints(
non_nullable=non_nullable, unique=unique, ignore_missing_vals=ignore_missing_vals
),
is_required=is_required,
)
@staticmethod
def boolean_column(
name, non_nullable=False, unique=False, ignore_missing_vals=False, is_required=None
):
"""Simple constructor for PandasColumns that expresses boolean constraints on boolean dtypes.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
non_nullable (Optional[bool]): If true, this column will enforce a constraint that all values in the column
ought to be non null values.
unique (Optional[bool]): If true, this column will enforce a uniqueness constraint on the column values.
ignore_missing_vals (Optional[bool]): A flag that is passed into most constraints. If true, the constraint will
only evaluate non-null data. Ignore_missing_vals and non_nullable cannot both be True.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If the column exists the validate function will validate the column. Default to True.
"""
return PandasColumn(
name=check.str_param(name, "name"),
constraints=[ColumnDTypeFnConstraint(is_bool_dtype)]
+ _construct_keyword_constraints(
non_nullable=non_nullable, unique=unique, ignore_missing_vals=ignore_missing_vals
),
is_required=is_required,
)
@staticmethod
def numeric_column(
name,
min_value=-float("inf"),
max_value=float("inf"),
non_nullable=False,
unique=False,
ignore_missing_vals=False,
is_required=None,
):
"""Simple constructor for PandasColumns that expresses numeric constraints numeric dtypes.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
min_value (Optional[Union[int,float]]): The lower bound for values you expect in this column. Defaults to -float('inf')
max_value (Optional[Union[int,float]]): The upper bound for values you expect in this column. Defaults to float('inf')
non_nullable (Optional[bool]): If true, this column will enforce a constraint that all values in the column
ought to be non null values.
unique (Optional[bool]): If true, this column will enforce a uniqueness constraint on the column values.
ignore_missing_vals (Optional[bool]): A flag that is passed into most constraints. If true, the constraint will
only evaluate non-null data. Ignore_missing_vals and non_nullable cannot both be True.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If the column exists the validate function will validate the column. Default to True.
"""
return PandasColumn(
name=check.str_param(name, "name"),
constraints=[
ColumnDTypeFnConstraint(is_numeric_dtype),
InRangeColumnConstraint(
check.numeric_param(min_value, "min_value"),
check.numeric_param(max_value, "max_value"),
ignore_missing_vals=ignore_missing_vals,
),
]
+ _construct_keyword_constraints(
non_nullable=non_nullable, unique=unique, ignore_missing_vals=ignore_missing_vals
),
is_required=is_required,
)
@staticmethod
def integer_column(
name,
min_value=-float("inf"),
max_value=float("inf"),
non_nullable=False,
unique=False,
ignore_missing_vals=False,
is_required=None,
):
"""Simple constructor for PandasColumns that expresses numeric constraints on integer dtypes.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
min_value (Optional[Union[int,float]]): The lower bound for values you expect in this column. Defaults to -float('inf')
max_value (Optional[Union[int,float]]): The upper bound for values you expect in this column. Defaults to float('inf')
non_nullable (Optional[bool]): If true, this column will enforce a constraint that all values in the column
ought to be non null values.
unique (Optional[bool]): If true, this column will enforce a uniqueness constraint on the column values.
ignore_missing_vals (Optional[bool]): A flag that is passed into most constraints. If true, the constraint will
only evaluate non-null data. Ignore_missing_vals and non_nullable cannot both be True.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If the column exists the validate function will validate the column. Default to True.
"""
return PandasColumn(
name=check.str_param(name, "name"),
constraints=[
ColumnDTypeFnConstraint(is_integer_dtype),
InRangeColumnConstraint(
check.numeric_param(min_value, "min_value"),
check.numeric_param(max_value, "max_value"),
ignore_missing_vals=ignore_missing_vals,
),
]
+ _construct_keyword_constraints(
non_nullable=non_nullable, unique=unique, ignore_missing_vals=ignore_missing_vals
),
is_required=is_required,
)
@staticmethod
def float_column(
name,
min_value=-float("inf"),
max_value=float("inf"),
non_nullable=False,
unique=False,
ignore_missing_vals=False,
is_required=None,
):
"""Simple constructor for PandasColumns that expresses numeric constraints on float dtypes.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
min_value (Optional[Union[int,float]]): The lower bound for values you expect in this column. Defaults to -float('inf')
max_value (Optional[Union[int,float]]): The upper bound for values you expect in this column. Defaults to float('inf')
non_nullable (Optional[bool]): If true, this column will enforce a constraint that all values in the column
ought to be non null values.
unique (Optional[bool]): If true, this column will enforce a uniqueness constraint on the column values.
ignore_missing_vals (Optional[bool]): A flag that is passed into most constraints. If true, the constraint will
only evaluate non-null data. Ignore_missing_vals and non_nullable cannot both be True.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If the column exists the validate function will validate the column. Default to True.
"""
return PandasColumn(
name=check.str_param(name, "name"),
constraints=[
ColumnDTypeFnConstraint(is_float_dtype),
InRangeColumnConstraint(
check.numeric_param(min_value, "min_value"),
check.numeric_param(max_value, "max_value"),
ignore_missing_vals=ignore_missing_vals,
),
]
+ _construct_keyword_constraints(
non_nullable=non_nullable, unique=unique, ignore_missing_vals=ignore_missing_vals
),
is_required=is_required,
)
@staticmethod
def datetime_column(
name,
min_datetime=Timestamp.min,
max_datetime=Timestamp.max,
non_nullable=False,
unique=False,
ignore_missing_vals=False,
is_required=None,
tz=None,
):
"""Simple constructor for PandasColumns that expresses datetime constraints on 'datetime64[ns]' dtypes.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
min_datetime (Optional[Union[int,float]]): The lower bound for values you expect in this column.
Defaults to pandas.Timestamp.min.
max_datetime (Optional[Union[int,float]]): The upper bound for values you expect in this column.
Defaults to pandas.Timestamp.max.
non_nullable (Optional[bool]): If true, this column will enforce a constraint that all values in the column
ought to be non null values.
unique (Optional[bool]): If true, this column will enforce a uniqueness constraint on the column values.
ignore_missing_vals (Optional[bool]): A flag that is passed into most constraints. If true, the constraint will
only evaluate non-null data. Ignore_missing_vals and non_nullable cannot both be True.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If the column exists the validate function will validate the column. Default to True.
tz (Optional[str]): Required timezone for values eg: tz='UTC', tz='Europe/Dublin', tz='US/Eastern'.
Defaults to None, meaning naive datetime values.
"""
if tz is None:
datetime_constraint = ColumnDTypeInSetConstraint({"datetime64[ns]"})
else:
datetime_constraint = ColumnDTypeInSetConstraint({f"datetime64[ns, {tz}]"})
# One day more/less than absolute min/max to prevent OutOfBoundsDatetime errors when converting min/max to be tz aware
if min_datetime.tz_localize(None) == Timestamp.min:
min_datetime = Timestamp("1677-09-22 00:12:43.145225Z")
if max_datetime.tz_localize(None) == Timestamp.max:
max_datetime = Timestamp("2262-04-10 23:47:16.854775807Z")
# Convert bounds to same tz
if Timestamp(min_datetime).tz is None:
min_datetime = Timestamp(min_datetime).tz_localize(tz)
if Timestamp(max_datetime).tz is None:
max_datetime = Timestamp(max_datetime).tz_localize(tz)
return PandasColumn(
name=check.str_param(name, "name"),
constraints=[
datetime_constraint,
InRangeColumnConstraint(
min_datetime, max_datetime, ignore_missing_vals=ignore_missing_vals
),
]
+ _construct_keyword_constraints(
non_nullable=non_nullable, unique=unique, ignore_missing_vals=ignore_missing_vals
),
is_required=is_required,
)
@staticmethod
def string_column(
name, non_nullable=False, unique=False, ignore_missing_vals=False, is_required=None
):
"""Simple constructor for PandasColumns that expresses constraints on string dtypes.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
non_nullable (Optional[bool]): If true, this column will enforce a constraint that all values in the column
ought to be non null values.
unique (Optional[bool]): If true, this column will enforce a uniqueness constraint on the column values.
ignore_missing_vals (Optional[bool]): A flag that is passed into most constraints. If true, the constraint will
only evaluate non-null data. Ignore_missing_vals and non_nullable cannot both be True.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If the column exists the validate function will validate the column. Default to True.
"""
return PandasColumn(
name=check.str_param(name, "name"),
constraints=[ColumnDTypeFnConstraint(is_string_dtype)]
+ _construct_keyword_constraints(
non_nullable=non_nullable, unique=unique, ignore_missing_vals=ignore_missing_vals
),
is_required=is_required,
)
@staticmethod
def categorical_column(
name,
categories,
of_types=frozenset({"category", "object"}),
non_nullable=False,
unique=False,
ignore_missing_vals=False,
is_required=None,
):
"""Simple constructor for PandasColumns that expresses categorical constraints on specified dtypes.
Args:
name (str): Name of the column. This must match up with the column name in the dataframe you
expect to receive.
categories (List[Any]): The valid set of buckets that all values in the column must match.
of_types (Optional[Union[str, Set[str]]]): The expected dtype[s] that your categories and values must
abide by.
non_nullable (Optional[bool]): If true, this column will enforce a constraint that all values in
the column ought to be non null values.
unique (Optional[bool]): If true, this column will enforce a uniqueness constraint on the column values.
ignore_missing_vals (Optional[bool]): A flag that is passed into most constraints. If true, the
constraint will only evaluate non-null data. Ignore_missing_vals and non_nullable cannot both be True.
is_required (Optional[bool]): Flag indicating the optional/required presence of the column.
If the column exists the validate function will validate the column. Default to True.
"""
of_types = {of_types} if isinstance(of_types, str) else of_types
return PandasColumn(
name=check.str_param(name, "name"),
constraints=[
ColumnDTypeInSetConstraint(of_types),
CategoricalColumnConstraint(categories, ignore_missing_vals=ignore_missing_vals),
]
+ _construct_keyword_constraints(
non_nullable=non_nullable, unique=unique, ignore_missing_vals=ignore_missing_vals
),
is_required=is_required,
)
def validate_constraints(dataframe, pandas_columns=None, dataframe_constraints=None):
dataframe = check.inst_param(dataframe, "dataframe", DataFrame)
pandas_columns = check.opt_list_param(
pandas_columns, "column_constraints", of_type=PandasColumn
)
dataframe_constraints = check.opt_list_param(
dataframe_constraints, "dataframe_constraints", of_type=DataFrameConstraint
)
if pandas_columns:
for column in pandas_columns:
column.validate(dataframe)
if dataframe_constraints:
for dataframe_constraint in dataframe_constraints:
dataframe_constraint.validate(dataframe)