When using flask caching with File System, got an error of The process cannot access the file because it is being used by another process

Dash Python
1

Hi

I am following below example on using flask caching with File system to store a big dataframe which will be used repeatedly during different callbacks. Basically I’d like to cache that big dataframe so next time when callback, I don’t need to read it again.

And I always get an error of

delete key ‘main.get_longterm_dts_data_cache_memver’ → [WinError 32] The process cannot access the file because it is being used by another process: ‘cache-directory\3177d6ff18b798f403b4140f08f9fe90’

I don’t know why file is used by another process. I have no idea how to fix it.

Anyone help? Thank you so much


app = JupyterDash(__name__,
                 external_stylesheets=[
                 "https://stackpath.bootstrapcdn.com/bootswatch/4.5.0/flatly/bootstrap.min.css"
                 ],
                 suppress_callback_exceptions=True
                 )

cache = Cache(app.server, config={
    'CACHE_TYPE': 'filesystem',
    'CACHE_DIR': 'cache-directory'
})

TIMEOUT = 60

    df_DTS_all_longterm= pd.read_json(
                    get_longterm_dts_data_cache(wellname,dts_longterm_filename_list,start_date_prod,end_date_prod,  # on;y need to process the first filename under the dropdown list
                        need_multile_dts_file,dts_data_frequency,dts_well_depth_min,dts_depth_grouping,dts_data_export,
                        dts_missing_percent_resample), 
                    orient='split')

@cache.memoize(timeout=TIMEOUT)
def get_longterm_dts_data_cache(wellname,dts_longterm_filename_list,start_date_prod,end_date_prod,
                          need_multile_dts_file,dts_data_frequency,dts_well_depth_min,dts_depth_grouping,dts_data_export,
                          dts_missing_percent_resample):
return df_DTS_all_longterm.to_json(date_format='iso', orient='split')
2

anyone can help? the error is:

delete key ‘main .get_longterm_dts_data_cache_memver’ → [WinError 32] The process cannot access the file because it is being used by another process: ‘cache-directory\3177d6ff18b798f403b4140f08f9fe90’

get_longterm_dts_data is the function name using flask caching.

Thanks