Example of pickleless numpy serialization

datetime64_safe_serialization.py

# coding=UTF-8
import io
import multiprocessing

import numpy


def numpy_dumps(numpy_array):
    """Safely pickle numpy array to string.

    Args:
        numpy_array (numpy.ndarray): arbitrary numpy array.

    Returns:
        A string representation of the array that can be loaded using
        `numpy_loads.

    """
    with io.BytesIO() as file_stream:
        numpy.save(file_stream, numpy_array, allow_pickle=False)
        return file_stream.getvalue()


def numpy_loads(binary_numpy_string):
    """Safely unpickle binary string to numpy array.

    Args:
        binary_numpy_string (str): binary string representing a pickled
            numpy array.

    Returns:
        A numpy representation of ``binary_numpy_string``.

    """
    with io.BytesIO(binary_numpy_string) as file_stream:
        return numpy.load(file_stream)


array_in = numpy.empty(1, dtype='datetime64,f4')
print(array_in.dtype['f0'].metadata)  # prints None

q = multiprocessing.Queue()
# safely pickle the array
q.put(numpy_dumps(array_in))

# unpickle the result
array_out = numpy_loads(q.get())
print(array_out.dtype['f0'].metadata)  # prints None
numpy.save('out', array_out)  # totally fine