chore: import upstream snapshot with attribution

swift/utils/shutdown_manager.py

@@ -0,0 +1,35 @@
+import os
+import signal
+
+
+class ShutdownManager:
+
+    def __init__(self, signals=None, stop_file=None):
+        if signals is None:
+            signals = [signal.SIGTERM, signal.SIGINT, signal.SIGUSR1, signal.SIGUSR2]
+        self._signals = signals
+        self._stop_file = stop_file or '/tmp/stop'
+
+        self._shutdown_requested = False
+        self._old_handlers = {}
+
+    def _handler(self, signum, frame):
+        self._shutdown_requested = True
+
+    def register(self):
+        for s in self._signals:
+            self._old_handlers[s] = signal.getsignal(s)
+            signal.signal(s, self._handler)
+
+    def unregister(self):
+        for s, handler in self._old_handlers.items():
+            signal.signal(s, handler)
+        self._old_handlers = {}
+
+    def should_shutdown(self) -> bool:
+        if self._shutdown_requested:
+            return True
+        return os.path.exists(self._stop_file)
+
+    def reset(self):
+        self._shutdown_requested = False