Source code for bokeh.util.dependencies

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# Copyright (c) 2012 - 2020, Anaconda, Inc., and Bokeh Contributors.
# All rights reserved.
#
# The full license is in the file LICENSE.txt, distributed with this software.
#-----------------------------------------------------------------------------
''' Utilities for checking dependencies

'''

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# Boilerplate
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import logging # isort:skip
log = logging.getLogger(__name__)

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# Imports
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# Standard library imports
from importlib import import_module
from types import ModuleType
from typing import Optional

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# Globals and constants
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__all__ = (
    'import_optional',
    'import_required',
)

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# General API
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[docs]def import_optional(mod_name: str) -> Optional[ModuleType]: ''' Attempt to import an optional dependency. Silently returns None if the requested module is not available. Args: mod_name (str) : name of the optional module to try to import Returns: imported module or None, if import fails ''' try: return import_module(mod_name) except ImportError: pass except Exception: msg = "Failed to import optional module `{}`".format(mod_name) log.exception(msg) return None
[docs]def import_required(mod_name: str, error_msg: str) -> ModuleType: ''' Attempt to import a required dependency. Raises a RuntimeError if the requested module is not available. Args: mod_name (str) : name of the required module to try to import error_msg (str) : error message to raise when the module is missing Returns: imported module Raises: RuntimeError ''' try: return import_module(mod_name) except ImportError as e: raise RuntimeError(error_msg) from e
#----------------------------------------------------------------------------- # Dev API #----------------------------------------------------------------------------- #----------------------------------------------------------------------------- # Private API #----------------------------------------------------------------------------- #----------------------------------------------------------------------------- # Code #-----------------------------------------------------------------------------