[datasets] Add an env var for progress bar behavior (#20586)

Adds a RAY_DATA_DISABLE_PROGRESS_BARS env var to control the default progress bar behavior. The default value is "0". Setting it to "1" disables progress bars, unless they are reenabled again by the set_progress_bars method.

python/ray/data/impl/progress_bar.py

@@ -1,6 +1,7 @@
 from typing import List, Any
 
 import ray
+from ray.ray_constants import env_integer
 from ray.types import ObjectRef
 from ray.util.annotations import PublicAPI
 
@@ -12,13 +13,18 @@ except ImportError:
     needs_warning = True
 
 # Whether progress bars are enabled in this process.
-_enabled: bool = True
+_enabled: bool = not bool(env_integer("RAY_DATA_DISABLE_PROGRESS_BARS", 0))
 
 
 @PublicAPI
 def set_progress_bars(enabled: bool) -> bool:
     """Set whether progress bars are enabled.
 
+    The default behavior is controlled by the
+    ``RAY_DATA_DISABLE_PROGRESS_BARS`` environment variable. By default,
+    it is set to "0". Setting it to "1" will disable progress bars, unless
+    they are reenabled by this method.
+
     Returns:
         Whether progress bars were previously enabled.
     """