114 lines
3.9 KiB
Python
114 lines
3.9 KiB
Python
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import inspect
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from functools import partial
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try:
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from joblib.externals.cloudpickle import dumps, loads
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cloudpickle = True
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except ImportError:
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cloudpickle = False
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WRAP_CACHE = dict()
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class CloudpickledObjectWrapper(object):
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def __init__(self, obj, keep_wrapper=False):
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self._obj = obj
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self._keep_wrapper = keep_wrapper
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def __reduce__(self):
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_pickled_object = dumps(self._obj)
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if not self._keep_wrapper:
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return loads, (_pickled_object,)
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return _reconstruct_wrapper, (_pickled_object, self._keep_wrapper)
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def __getattr__(self, attr):
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# Ensure that the wrapped object can be used seemlessly as the
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# previous object.
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if attr not in ['_obj', '_keep_wrapper']:
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return getattr(self._obj, attr)
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return getattr(self, attr)
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# Make sure the wrapped object conserves the callable property
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class CallableObjectWrapper(CloudpickledObjectWrapper):
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def __call__(self, *args, **kwargs):
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return self._obj(*args, **kwargs)
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def _wrap_non_picklable_objects(obj, keep_wrapper):
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if callable(obj):
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return CallableObjectWrapper(obj, keep_wrapper=keep_wrapper)
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return CloudpickledObjectWrapper(obj, keep_wrapper=keep_wrapper)
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def _reconstruct_wrapper(_pickled_object, keep_wrapper):
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obj = loads(_pickled_object)
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return _wrap_non_picklable_objects(obj, keep_wrapper)
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def _wrap_objects_when_needed(obj):
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# Function to introspect an object and decide if it should be wrapped or
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# not.
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if not cloudpickle:
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return obj
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need_wrap = "__main__" in getattr(obj, "__module__", "")
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if isinstance(obj, partial):
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return partial(
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_wrap_objects_when_needed(obj.func),
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*[_wrap_objects_when_needed(a) for a in obj.args],
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**{k: _wrap_objects_when_needed(v)
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for k, v in obj.keywords.items()}
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)
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if callable(obj):
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# Need wrap if the object is a function defined in a local scope of
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# another function.
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func_code = getattr(obj, "__code__", "")
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need_wrap |= getattr(func_code, "co_flags", 0) & inspect.CO_NESTED
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# Need wrap if the obj is a lambda expression
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func_name = getattr(obj, "__name__", "")
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need_wrap |= "<lambda>" in func_name
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if not need_wrap:
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return obj
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wrapped_obj = WRAP_CACHE.get(obj)
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if wrapped_obj is None:
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wrapped_obj = _wrap_non_picklable_objects(obj, keep_wrapper=False)
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WRAP_CACHE[obj] = wrapped_obj
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return wrapped_obj
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def wrap_non_picklable_objects(obj, keep_wrapper=True):
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"""Wrapper for non-picklable object to use cloudpickle to serialize them.
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Note that this wrapper tends to slow down the serialization process as it
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is done with cloudpickle which is typically slower compared to pickle. The
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proper way to solve serialization issues is to avoid defining functions and
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objects in the main scripts and to implement __reduce__ functions for
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complex classes.
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"""
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if not cloudpickle:
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raise ImportError("could not from joblib.externals import cloudpickle. Please install "
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"cloudpickle to allow extended serialization. "
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"(`pip install cloudpickle`).")
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# If obj is a class, create a CloudpickledClassWrapper which instantiates
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# the object internally and wrap it directly in a CloudpickledObjectWrapper
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if inspect.isclass(obj):
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class CloudpickledClassWrapper(CloudpickledObjectWrapper):
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def __init__(self, *args, **kwargs):
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self._obj = obj(*args, **kwargs)
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self._keep_wrapper = keep_wrapper
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CloudpickledClassWrapper.__name__ = obj.__name__
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return CloudpickledClassWrapper
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# If obj is an instance of a class, just wrap it in a regular
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# CloudpickledObjectWrapper
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return _wrap_non_picklable_objects(obj, keep_wrapper=keep_wrapper)
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