Added watchdog module

hc_spider/watchdog.py

@@ -0,0 +1,36 @@
+import os
+import threading
+import time
+
+from hc_spider.model import SharedObjects
+
+
+class Watchdog(threading.Thread):
+    _shared_objects: SharedObjects
+
+    def __init__(self, **kwargs) -> None:
+        self._shared_objects = SharedObjects(**kwargs)
+        super().__init__()
+        self.daemon = True
+        self.name = "Watchdog"
+
+    def run(self) -> None:
+        print(f"{self.name} started with pid [{os.getpid()}]")
+        fifo_file = self._shared_objects.config.get("watchdog_file")
+        if os.path.exists(fifo_file) is False:
+            os.mkfifo(fifo_file)
+
+        with open(fifo_file) as f:
+            while True:
+                time.sleep(1)
+                data = f.read().strip("\n")
+                match data:
+                    case "exit":
+                        self._shared_objects.shutdown_event.set()
+                        self._shared_objects.watchdog_event.set()
+                        break
+
+        print(f"[{self.name}] is shutting down", flush=True)
+
+    def __del__(self) -> None:
+        print(f"[{self.name}] exited", flush=True)