test.py

"""
I'm trying to save the results of a session (stored
in the session dictionary) after the user has exited 
the Gooey interface. This worked in a previous version 
where I was using the click CLI module but when I added
Gooey, only the initial values stored in the session
dictionary are available upon script termination.

Requires:
Gooey
watchdog
Python3

Use:
python3 test.py

In the Gooey interface, select a folder.
Create a file ending in 'txt'
The file event should display in the Gooey window
and the event count should increment (by 1 or 2 depending
on your OS) and the updated event list will display.
Press Stop button and confirm by pressing Yes button
Expected the full event list (session['events']) to be
printed in the terminal. Instead only the initial values
are printed.
"""

import atexit
import time
import os
from gooey import Gooey, GooeyParser
from watchdog.observers import Observer
from watchdog.events import PatternMatchingEventHandler

# Create a test dict which will be modified in each function
# except those in the ImageHandler class
test_dict = {}
test_dict['value'] = 'initial'
session = {}
# Add fake dict for events key to see if it persists until app terminates
session['events'] = [{'event_type':'initial', 'src_path':'initial', 'dest_path':'initial'}]
print(session['events'])
print(test_dict)


class ImageHandler(PatternMatchingEventHandler):
    def on_any_event(self, event):
        # I don't think global is needed here, it doesn't help, but testing in case
        global session
        if hasattr(event, 'event_type'):
            event_type = event.event_type
        else:
            event_type = None
        if hasattr(event, 'src_path'):
            src_path = event.src_path
        else:
            src_path = None
        if hasattr(event, 'dest_path'):
            dest_path = event.dest_path
        else:
            dest_path = None
        event = {'event_type':event_type, 'src_path':src_path, 'dest_path':dest_path}
        print('New file event:', event)
        session['events'].append(event)
        # Printing to confirm all events are registered
        print('All file events:')
        print(session['events'])


@Gooey(program_name='Test')
def main():
    global session
    test_dict['value'] = 'in main'
    print(test_dict)
    client_parser = GooeyParser(description='Test Description')
    client_parser.add_argument('directory', help='Specify  directory.', widget="DirChooser")
    args = client_parser.parse_args()
    observed_path = os.path.abspath(args.directory)
    # Just testing with txt files for now
    # Generate new file events by creating, renaming, deleting .txt files in chosen directory
    event_handler = ImageHandler(patterns=['*.txt'])
    observer = Observer()
    observer.schedule(event_handler, observed_path, recursive=True)
    observer.start()
    try:
        while True:
            time.sleep(1)
            # Printing event count to confirm that session var is in scope
            print('Event count:{}'.format(len(session['events'])))
    except KeyboardInterrupt:
        # This is a holdover from the click CLI
        # Kept for testing
        print('Ending by KeyboardInterrupt')


def end_session():
    test_dict['value'] = 'ending'
    print(test_dict)
    print(session['events'])
    print('Above value is the initial value of session[events], not the expected list generated during execution.')


if __name__ == '__main__':
    # Using atexit because I don't know another way to call a function
    # when user terminates script via Gooey window.
    atexit.register(end_session)
    main()