Caches your Stan model, and recompiles if it has changed since the cache was created.

stan-model-cache.py

import pystan
import pickle
import os.path, time

def compile_model():
    with open('model.stan', 'r') as my_file:
        model_code = my_file.read()

    stan_model = pystan.StanModel(model_code=model_code)

    print('Compilation finished, writing to pickle.')

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

    return stan_model

def get_model():
    try:
        model_edited = os.path.getmtime('model.stan')
        pickle_edited = os.path.getmtime('model.pkl')

        if model_edited > pickle_edited:
            print('Model has been changed, recompiling.')
            return compile_model()

        print('Trying pre-compiled model.')
        return pickle.load(open('model.pkl', 'rb'))

    except FileNotFoundError as exception:
        print('Pre-compiled model not found. Compiling model.')

        return compile_model()