"""module lazyloader.""" import importlib import sys import types class LazyLoader(types.ModuleType): """Lazily import a module, mainly to avoid pulling in large dependencies. We use this for tensorflow and other optional libraries primarily at the top module level. """ # The lint error here is incorrect. def __init__( self, local_name, # pylint: disable=super-on-old-class parent_module_globals, name, warning=None, ): self._local_name = local_name self._parent_module_globals = parent_module_globals self._warning = warning super().__init__(str(name)) def _load(self): """Load the module and insert it into the parent's globals.""" # Import the target module and insert it into the parent's namespace module = importlib.import_module(self.__name__) self._parent_module_globals[self._local_name] = module # print("import", self.__name__) # print("Set global", self._local_name) # print("mod", module) sys.modules[self._local_name] = module # Emit a warning if one was specified if self._warning: print(self._warning) # noqa: T201 # Make sure to only warn once. self._warning = None # Update this object's dict so that if someone keeps a reference to the # LazyLoader, lookups are efficient (__getattr__ is only called on lookups # that fail). self.__dict__.update(module.__dict__) return module # def __getattribute__(self, item): # print("getattribute", item) def __getattr__(self, item): # print("getattr", item) module = self._load() return getattr(module, item) def __dir__(self): # print("dir") module = self._load() return dir(module)