When using Loggly with Python, I log with restapi-logging-handler's LogglyHandler. It's easy to configure, uses threads to compelte the logging asynchronously, and just works. There's more thorough documentation on the GitHub site, but basically you can pip install it:

pip install restapi-logging-handler

Then it's just a matter of configuring the handler:

from restapi_logging_handler import LogglyHandler


logglyHandler = LogglyHandler(
    custom_token='loggly-custom-key',
    app_tags=['tag1', 'tag2', ...],
    interval=1.0,
    max_attemps=5
)

Then, attach that handler to your logger and you're good to go.