Here is a snippet that attaches two log handlers to the root logger. Note

configure_logging()

is called outside of the task. If

configure_logging()

is moved inside the task, exceptions are raised.

import logging
import sys

import prefect
from prefect import Flow, task


def configure_logging():
    #logger = prefect.utilities.logging.get_logger()
    logger = logging.getLogger()

    # If your logger is the root logger, you may want to set it to INFO or DEBUG
    logger.setLevel('INFO')

    handler = logging.FileHandler('mylog.log', encoding='utf-8')
    handler2 = logging.StreamHandler(sys.stdout)

    formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s',
                                  datefmt='%Y-%m-%d_%H:%M:%S')

    handler.setFormatter(formatter)
    handler2.setFormatter(formatter)

    logger.addHandler(handler)
    logger.addHandler(handler2)

# configure logging outside of task
configure_logging()

@task(log_stdout=True)
def log_something():
    <http://logging.info|logging.info>('Hello')

with Flow('log-test') as flow:
    log_something()


flow.run()