Add maximum_refresh_time to progress_bar() (#147)

* Add maximum_refresh_time to progress_bar()

* None as default

audeer/core/tqdm.py

@@ -1,4 +1,6 @@
-from typing import Sequence
+import threading
+import time
+import typing
 
 from tqdm import tqdm
 
@@ -42,11 +44,12 @@ def format_display_message(text: str, pbar: bool = False) -> str:
 
 
 def progress_bar(
-    iterable: Sequence = None,
+    iterable: typing.Sequence = None,
     *,
     total: int = None,
     desc: str = None,
     disable: bool = False,
+    maximum_refresh_time: float = None,
 ) -> tqdm:
     r"""Progress bar with optional text on the right.
 
@@ -80,19 +83,67 @@ def progress_bar(
         total: total number of iterations
         desc: text shown on the right of the progress bar
         disable: don't show the display bar
+        maximum_refresh_time: refresh the progress bar
+            at least every ``maximum_refresh_time`` seconds,
+            using another thread.
+            If ``None``,
+            no refreshing is enforced
 
     Returns:
         progress bar object
 
     """
     if desc is None:
         desc = ""
-    return tqdm(
+    return tqdm_wrapper(
         iterable=iterable,
+        maximum_refresh_time=maximum_refresh_time,
         ncols=config.TQDM_COLUMNS,
         bar_format=config.TQDM_FORMAT,
         total=total,
         disable=disable,
         desc=format_display_message(desc, pbar=True),
         leave=config.TQDM_LEAVE,
     )
+
+
+def tqdm_wrapper(
+    iterable: typing.Sequence,
+    maximum_refresh_time: float,
+    *args,
+    **kwargs,
+) -> tqdm:
+    r"""Tqdm progress bar wrapper to enforce update once a second.
+
+    When using tqdm with large time durations
+    between single steps of the iteration,
+    it will not automatically update the elapsed time,
+    but needs to be forced,
+    see https://github.com/tqdm/tqdm/issues/861#issuecomment-2197893883.
+
+    Args:
+        iterable: sequence to iterate through
+        maximum_refresh_time: refresh the progress bar
+            at least every ``maximum_refresh_time`` seconds,
+            using another thread.
+            If ``None``,
+            no refreshing is enforced
+        args: arguments passed on to ``tqdm``
+        kwargs: keyword arguments passed on to ``tqdm``
+
+    Returns:
+        progress bar object
+
+    """
+    pbar = tqdm(iterable, *args, **kwargs)
+
+    def refresh():
+        while not pbar.disable:
+            time.sleep(maximum_refresh_time)
+            pbar.refresh()
+
+    if maximum_refresh_time is not None:
+        thread = threading.Thread(target=refresh, daemon=True)
+        thread.start()
+
+    return pbar

tests/test_tqdm.py

@@ -37,3 +37,15 @@ def test_progress_bar():
     pbar = audeer.progress_bar([0.1])
     for step in pbar:
         time.sleep(step)
+
+
+def test_progress_bar_update():
+    r"""Ensure progress bar is refreshed.
+
+    If the progress bar has to wait for a long time
+    until it would get updated,
+    we enforce an update by a given time.
+
+    """
+    for _ in audeer.progress_bar(range(2), maximum_refresh_time=0.01):
+        time.sleep(0.05)