Refactor model download progress tracking and enhance SSE handling

- Rearranged imports for consistency in useModelDownloadToast hook.
- Improved logging in useModelDownloadToast for better debugging during download events.
- Updated progress calculation to handle cases where progress exceeds 100%.
- Enhanced toast notifications to reflect download completion and error states.
- Introduced throttling in ProgressManager to optimize SSE updates and prevent overwhelming clients.
- Added new test scripts for monitoring SSE events during model downloads, ensuring accurate progress reporting.

backend/utils/hf_progress.py

@@ -32,7 +32,6 @@ class HFProgressTracker:
             """A tqdm subclass that reports progress to our tracker."""
 
             def __init__(self, *args, **kwargs):
-                print(f"[DEBUG TrackedTqdm] __init__ called with desc: {kwargs.get('desc', '')}")
                 # Extract filename from desc before passing to parent
                 desc = kwargs.get("desc", "")
                 if not desc and args:
@@ -81,7 +80,6 @@ class HFProgressTracker:
                     }
             
             def update(self, n=1):
-                print(f"[DEBUG TrackedTqdm] update called with n={n}, filter_non_downloads={tracker.filter_non_downloads}")
                 result = super().update(n)
 
                 # Report progress
@@ -121,10 +119,7 @@ class HFProgressTracker:
             
             def _is_download_progress(self, filename: str) -> bool:
                 """Check if this is a real download progress bar vs internal processing."""
-                print(f"[DEBUG _is_download_progress] Checking filename: '{filename}'")
-                
                 if not filename or filename == "unknown":
-                    print(f"[DEBUG _is_download_progress] Rejected: empty/unknown filename")
                     return False
                 
                 # Real downloads have file extensions
@@ -141,9 +136,7 @@ class HFProgressTracker:
                 skip_patterns = ['segment', 'processing', 'generating', 'loading']
                 has_skip_pattern = any(pattern in filename_lower for pattern in skip_patterns)
                 
-                result = has_extension and not has_skip_pattern
-                print(f"[DEBUG _is_download_progress] has_extension={has_extension}, has_skip_pattern={has_skip_pattern}, result={result}")
-                return result
+                return has_extension and not has_skip_pattern
             
             def close(self):
                 with tracker._lock:
@@ -156,13 +149,11 @@ class HFProgressTracker:
     @contextmanager
     def patch_download(self):
         """Context manager to patch tqdm for progress tracking."""
-        print("[DEBUG HFProgressTracker] patch_download called")
         try:
             import tqdm as tqdm_module
 
             # Store original tqdm class
             self._original_tqdm_class = tqdm_module.tqdm
-            print(f"[DEBUG HFProgressTracker] Original tqdm class: {self._original_tqdm_class}")
             
             # Reset totals
             with self._lock:
@@ -175,22 +166,18 @@ class HFProgressTracker:
             
             # Create our tracked tqdm class
             tracked_tqdm = self._create_tracked_tqdm_class()
-            print(f"[DEBUG HFProgressTracker] Created TrackedTqdm class: {tracked_tqdm}")
 
             # Patch tqdm.tqdm
             tqdm_module.tqdm = tracked_tqdm
-            print(f"[DEBUG HFProgressTracker] Patched tqdm.tqdm")
 
             # Also patch tqdm.auto.tqdm if it exists (used by huggingface_hub)
             self._original_tqdm_auto = None
             if hasattr(tqdm_module, "auto") and hasattr(tqdm_module.auto, "tqdm"):
                 self._original_tqdm_auto = tqdm_module.auto.tqdm
                 tqdm_module.auto.tqdm = tracked_tqdm
-                print(f"[DEBUG HFProgressTracker] Patched tqdm.auto.tqdm")
             
             # Patch in sys.modules to catch already-imported references
             self._patched_modules = {}
-            patched_count = 0
             for module_name in list(sys.modules.keys()):
                 if "huggingface" in module_name or module_name.startswith("tqdm"):
                     try:
@@ -203,11 +190,8 @@ class HFProgressTracker:
                             ):
                                 self._patched_modules[module_name] = attr
                                 setattr(module, "tqdm", tracked_tqdm)
-                                patched_count += 1
-                                print(f"[DEBUG HFProgressTracker] Patched {module_name}.tqdm")
                     except (AttributeError, TypeError):
                         pass
-            print(f"[DEBUG HFProgressTracker] Patched {patched_count} modules in sys.modules")
             
             yield