Ensure one status thread is started per process

issue10335
review349751004

trytond/status.py

@@ -15,9 +15,14 @@ address = 'trytond-stat.socket'
 
 Process = namedtuple('Process', ['start_time', 'request'])
 
+_PID = None
+_PATH = None
+_LOCK = threading.Lock()
+
 
 @contextmanager
 def processing(request):
+    start(_PATH)  # check if running thread
     process = Process(time.perf_counter(), request)
     status[id(process)] = process
     try:
@@ -67,7 +72,14 @@ def dumper(path):
 
 
 def start(path):
-    threading.Thread(target=dumper, args=(path,), daemon=True).start()
+    global _PID, _PATH
+    if _PID != os.getpid() and path:  # Quick test without lock
+        with _LOCK:
+            if _PID != os.getpid():
+                threading.Thread(
+                    target=dumper, args=(path,), daemon=True).start()
+                _PID = os.getpid()
+                _PATH = path
 
 
 def listen(path, callback=None):