Tom Han
09/10/2025, 4:48 PMtqdm style progress bar inside a flow with log_prints set as true, would the progress bar overflown my logging space? I don't want that, but also the tdqm progress bar is not inside my code, so I am not sure if I can use the progress artifact to monkey patch it.Marvin
09/10/2025, 4:48 PMMarvin
09/10/2025, 4:54 PMlog_prints=True, tqdm’s updates will be captured as Prefect logs and can spam your logs. tqdm writes to stderr by default and emits frequent carriage-return updates; when captured, these often appear as many log lines.
Good ways to prevent log spam without modifying the third‑party code:
- Temporarily disable tqdm via environment variable
- This works even when the tqdm call is buried in a library.
- Wrap just the problematic call:
import os
from contextlib import contextmanager
@contextmanager
def disable_tqdm():
prev = os.environ.get("TQDM_DISABLE")
os.environ["TQDM_DISABLE"] = "1"
try:
yield
finally:
if prev is None:
os.environ.pop("TQDM_DISABLE", None)
else:
os.environ["TQDM_DISABLE"] = prev
with disable_tqdm():
third_party_fn()
- You can also set this env var in your deployment/worker environment.
- Redirect only stderr during the call (tqdm’s default output)
- Keeps your other `print`s logged while swallowing the progress bar:
from io import StringIO
from contextlib import redirect_stderr
with redirect_stderr(StringIO()):
third_party_fn()
- Temporarily disable Prefect’s print capture
- If you’re okay suppressing all print-capture for the block, use:
from prefect.logging import disable_run_logger
with disable_run_logger():
third_party_fn()
- This will stop Prefect from capturing prints (including tqdm) for the duration of the context, then re-enable logging afterward.
- Reduce tqdm’s chattiness (if you want to keep it visible)
- Set environment variables to slow down updates:
os.environ["TQDM_MININTERVAL"] = "5" # seconds between refreshes
os.environ["TQDM_MINiters"] = "100" # iterations between refreshes
- Docs: tqdm parameters
About Prefect progress artifacts
- Prefect doesn’t provide an automatic integration to “monkey‑patch” third‑party tqdm bars into artifacts. You’d need to call the artifact APIs yourself from your code.
- If you do control the loop, you can replace tqdm with a Progress artifact:
from prefect.artifacts import create_progress_artifact, update_progress_artifact
aid = create_progress_artifact(progress=0, key="my-step", description="Processing items")
for i, item in enumerate(items, 1):
# ... work ...
update_progress_artifact(aid, progress=100 * i / len(items))
- API reference/source: prefect.artifacts
Notes
- Very chatty output increases run overhead and can make logs hard to navigate in the UI. Prefer one of the suppression approaches above.
- Prefect logging docs: Prefect 3 logging API
Would you like help wiring one of these wrappers around a specific function where tqdm is being used? If you can share how you call the third‑party code, I can suggest the least invasive option.Bring your towel and join one of the fastest growing data communities. Welcome to our second-generation open source orchestration platform, a completely rethought approach to dataflow automation.
Powered by