# noqa: D205,D400
"""
CF-Convention checking
======================
Utilities designed to verify the compliance of metadata with the CF-Convention.
"""
import fnmatch
import re
from typing import Sequence, Union
from .options import cfcheck
from .utils import VARIABLES, ValidationError
# TODO: Implement pandas infer_freq in xarray with CFTimeIndex. >> PR pydata/xarray#4033
[docs]@cfcheck
def check_valid(var, key: str, expected: Union[str, Sequence[str]]):
r"""Check that a variable's attribute has one of the expected values. Raise a ValidationError otherwise."""
att = getattr(var, key, None)
if att is None:
raise ValidationError(f"Variable does not have a `{key}` attribute.")
if isinstance(expected, str):
expected = [expected]
for exp in expected:
if fnmatch.fnmatch(att, exp):
break
else:
raise ValidationError(
f"Variable has a non-conforming {key}: Got `{att}`, expected `{expected}`",
)
[docs]def cfcheck_from_name(varname, vardata):
"""Perform cfchecks on a DataArray using specifications from xclim's default variables."""
data = VARIABLES[varname]
if "cell_methods" in data:
_check_cell_methods(
getattr(vardata, "cell_methods", None), data["cell_methods"]
)
if "standard_name" in data:
check_valid(vardata, "standard_name", data["standard_name"])
@cfcheck
def _check_cell_methods(data_cell_methods: str, expected_method: str) -> None:
if data_cell_methods is None:
raise ValidationError("Variable does not have a `cell_methods` attribute.")
EXTRACT_CELL_METHOD_REGEX = r"(\s*\S+\s*:(\s+[\w()-]+)+)(?!\S*:)"
for m in re.compile(EXTRACT_CELL_METHOD_REGEX).findall(data_cell_methods):
if m[0].__contains__(expected_method):
return None
raise ValidationError(
f"Variable has a non-conforming cell_methods: "
f"Got `{data_cell_methods}`, which do not include the expected "
f"`{expected_method}`"
)