from pathlib import Path
import sys
import json
import pyhf.exceptions
from pyhf.schema import variables
# importlib.resources.as_file wasn't added until Python 3.9
# c.f. https://docs.python.org/3.9/library/importlib.html#importlib.resources.as_file
if sys.version_info >= (3, 9):
from importlib import resources
else:
import importlib_resources as resources
[docs]
def load_schema(schema_id: str):
"""
Get a schema by relative path from cache, or load it into the cache and return.
Args:
schema_id (str): Relative path to schema from :attr:`pyhf.schema.path`
Example:
>>> import pyhf
>>> schema = pyhf.schema.load_schema("1.0.0/defs.json")
>>> type(schema)
<class 'dict'>
>>> schema.keys()
dict_keys(['$schema', '$id', 'definitions'])
>>> pyhf.schema.load_schema("0.0.0/defs.json") # doctest: +ELLIPSIS
Traceback (most recent call last):
...
pyhf.exceptions.SchemaNotFound: ...
Returns:
schema (dict): The loaded schema.
Raises:
~pyhf.exceptions.SchemaNotFound: if the provided ``schema_id`` cannot be found.
"""
try:
return variables.SCHEMA_CACHE[
f'{Path(variables.SCHEMA_BASE).joinpath(schema_id)}'
]
except KeyError:
pass
ref = variables.schemas.joinpath(schema_id)
with resources.as_file(ref) as path:
if not path.exists():
raise pyhf.exceptions.SchemaNotFound(
f'The schema {schema_id} was not found. Do you have the right version or the right path? {path}'
)
with path.open(encoding="utf-8") as json_schema:
schema = json.load(json_schema)
variables.SCHEMA_CACHE[schema['$id']] = schema
return variables.SCHEMA_CACHE[schema['$id']]
# pre-populate the cache to avoid network access
# on first validation in standard usage
# (not in pyhf.schema.variables to avoid circular imports)
load_schema(f'{variables.SCHEMA_VERSION}/defs.json')