Log Formatter for Flask to trim pathname relative to app_root

FlaskAppFormatter.py

# app is flask app object
class FlaskAppFormatter(logging.Formatter):
    def format(self, record):
        if record.pathname and record.pathname.startswith(app.root_path):
            record.pathname = record.pathname.lstrip(app.root_path)

        return super(FlaskAppFormatter, self).format(record)