Incorrect log position

🐛 Bug description

When {bar} is removed from bar_format of argument of ProgressBar, immediate logger output does not print in newline.

Add

import logging

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

to beginning of mnist_with_tqdm_logger.py and change this line to

    pbar = ProgressBar(
        persist=True, bar_format="{desc}[{n_fmt}/{total_fmt}] {percentage:3.0f}%|{postfix} [{elapsed}<{remaining}]",
    )

This seems not happen to very small example

import logging
import time

import tqdm

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

logger.info("before")

for i in tqdm.tqdm(
    range(3),
    leave=True,
    bar_format="{desc}[{n_fmt}/{total_fmt}] {percentage:3.0f}%|{postfix} [{elapsed}<{remaining}]",
):
    time.sleep(0.5)

logger.info("after")

Note that the leave argument in tqdm corresponds to the persist in ProgressBar.

Environment

• PyTorch Version (e.g., 1.4): 1.5.0
• Ignite Version (e.g., 0.3.0): 2d30d1d
• OS (e.g., Linux): macOS 10.15.5
• How you installed Ignite (conda, pip, source): source
• Python version: 3.7.5
• Any other relevant information: None

[Yevgnen]

@vfdev-5 You are always fast 😃

[liebkne]

I have a similar issue, when handlers for Events.ITERATION_COMPLETED which lies between Events.EPOCH_STARTED and Events.EPOCH_COMPLETED output logs(e.g., adjust lr based on iteration and output a info message like lr adjusted to ...), they come after the progress bar if the {bar} is hidden.