databases/databases/importer.py at drop-python3.6 · pythonran/databases · GitHub

35 lines (28 loc) · 1.08 KB

import importlib

import typing

class ImportFromStringError(Exception):

pass

def import_from_string(import_str: str) -> typing.Any:

module_str, _, attrs_str = import_str.partition(":")

if not module_str or not attrs_str:

message = (

'Import string "{import_str}" must be in format "<module>:<attribute>".'

)

raise ImportFromStringError(message.format(import_str=import_str))

try:

module = importlib.import_module(module_str)

except ImportError as exc:

if exc.name != module_str:

raise exc from None

message = 'Could not import module "{module_str}".'

raise ImportFromStringError(message.format(module_str=module_str))

instance = module

try:

for attr_str in attrs_str.split("."):

instance = getattr(instance, attr_str)

except AttributeError as exc:

message = 'Attribute "{attrs_str}" not found in module "{module_str}".'

raise ImportFromStringError(

message.format(attrs_str=attrs_str, module_str=module_str)

)

return instance

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