fix multiprocessing logging mess (#2025)

Author: mikel-brostrom

boxmot/utils/__init__.py

@@ -6,6 +6,7 @@
 from pathlib import Path
 
 import numpy as np
+import multiprocessing as mp
 
 # global logger
 from loguru import logger
@@ -23,7 +24,17 @@
 
 NUM_THREADS = min(8, max(1, os.cpu_count() - 1))
 
-
-def only_main_thread(record):
-    # Check if the current thread is the main thread
-    return threading.current_thread().name == "MainThread"
+def _is_main_process(record):
+    return mp.current_process().name == "MainProcess"
+
+def configure_logging():
+    # this will remove *all* existing handlers and then add yours
+    logger.configure(handlers=[
+        {
+            "sink": sys.stderr,
+            "level":    "INFO",
+            "filter":   _is_main_process,
+        }
+    ])
+    
+configure_logging()