Can I define the logger globally?

[anna_geller]

Prefect 2.0

No, setting the logger globally (i.e. at a module scope) is not supported. You should define the logger and log messages within your tasks and flows instead. The following will raise a RuntimeError:

from prefect import get_run_logger

logger = get_run_logger()
logger.info("Starting the script...")

The output

Traceback (most recent call last):
  File "/Users/xxx/repos/orion/example.py", line 3, in <module>
    logger = get_run_logger()
  File "/Users/xxx/repos/orion/src/prefect/logging/loggers.py", line 91, in get_run_logger
    raise RuntimeError("There is no active flow or task run context.")
RuntimeError: There is no active flow or task run context.

To avoid such issues, set your logger and add your logs exclusively within tasks, flows, and subflows using the get_run_logger function, as described in this topic:

How can I add logs to my flow?

Prefect 2.0 Orion provides the get_run_logger function that returns a logging.Logger object. Retrieve the logger within the flow or task function and use it there. Here is how you can use it in your tasks, flows, and subflows: from prefect import task, get_run_logger @task def marvins_favorite_task(): logger = get_run_logger() logger.info("Hello from the Marvin's favorite task!")

An example flow with various log levels

from prefect import flow, task, get_run_logger @task def foo(): …

Prefect 1.0

Prefect 1.0 allows logging exclusively within tasks. Adding logs outside of Prefect tasks is not supported.