Getting TypeError: can't pickle _thread.RLock objects

Question

Read a number of similar questions, most of them mentioned that you shouldn\'t try to serialize an unserializable object. I am not able to understand the issue. I am able to sav

Answer 1

I was able to replicate your issue in TF 2.3.0 using Google Colab

import pickle
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense

model = Sequential()
model.add(Dense(1, input_dim=42, activation='sigmoid'))
model.compile(optimizer='adam', loss='categorical_crossentropy', metrics=['accuracy'])

with open('model.pkl', 'wb') as f:
    pickle.dump(model, f)

Output:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-1-afb2bf58a891> in <module>()
      8 
      9 with open('model.pkl', 'wb') as f:
---> 10     pickle.dump(model, f)

TypeError: can't pickle _thread.RLock objects

@adriangb, proposed hot fix to this issue in github for more details please refer this

import pickle

from tensorflow.keras.models import Sequential, Model
from tensorflow.keras.layers import Dense
from tensorflow.python.keras.layers import deserialize, serialize
from tensorflow.python.keras.saving import saving_utils


def unpack(model, training_config, weights):
    restored_model = deserialize(model)
    if training_config is not None:
        restored_model.compile(
            **saving_utils.compile_args_from_training_config(
                training_config
            )
        )
    restored_model.set_weights(weights)
    return restored_model

# Hotfix function
def make_keras_picklable():

    def __reduce__(self):
        model_metadata = saving_utils.model_metadata(self)
        training_config = model_metadata.get("training_config", None)
        model = serialize(self)
        weights = self.get_weights()
        return (unpack, (model, training_config, weights))

    cls = Model
    cls.__reduce__ = __reduce__

# Run the function
make_keras_picklable()

# Create the model
model = Sequential()
model.add(Dense(1, input_dim=42, activation='sigmoid'))
model.compile(optimizer='adam', loss='categorical_crossentropy', metrics=['accuracy'])

# Save
with open('model.pkl', 'wb') as f:
    pickle.dump(model, f)