Based on the research and GitHub discussions, I can provide some solutions to ensure your task logs are visible when running tasks in parallel. Here's what you need to know: 1. Use a More Robust Task Runner The default

ThreadPoolTaskRunner

can sometimes have issues with log visibility in parallel execution. Consider using either: -

DaskTaskRunner

for better logging handling in parallel execution -

RayTaskRunner

which provides better task isolation and logging capabilities 2. Configure Logging Level Make sure your logging level is set appropriately. You can set this through environment variables:

python
import logging
from prefect import flow, task

# Set logging level for your flow
logging.basicConfig(level=<http://logging.INFO|logging.INFO>)

3. Use Prefect's Built-in Logger Instead of using print statements, use Prefect's built-in logging functionality:

python
from prefect import flow, task, get_run_logger

@task
async def my_task(x):
    logger = get_run_logger()
    <http://logger.info|logger.info>(f"Processing {x}")
    # Your task logic here

4. Structured Task Definition When defining tasks that will run in parallel, make sure to structure them properly:

python
from prefect import flow, task

@task
async def parallel_task(item):
    logger = get_run_logger()
    <http://logger.info|logger.info>(f"Processing item: {item}")
    # Your task logic here

@flow
async def main_flow():
    # This will run tasks in parallel while maintaining proper logging
    results = await parallel_task.map([1, 2, 3, 4, 5])

5. Task Runner Configuration Example If you want to use Dask for better logging handling:

python
from prefect import flow
from prefect_dask.task_runners import DaskTaskRunner

@flow(task_runner=DaskTaskRunner())
def my_flow():
    # Your flow logic here

The key points to remember are: - Always use Prefect's

get_run_logger()

instead of print statements - Consider using

DaskTaskRunner

or

RayTaskRunner

for better parallel execution logging - Make sure your logging level is set appropriately - Structure your tasks properly for parallel execution These changes should help ensure your logs remain visible even when tasks are running concurrently. The logs will be properly captured and displayed in the Prefect UI and your console output. Would you like me to provide more specific examples for your use case or explain any of these solutions in more detail?