add systemd watchdog support

src/scat/writers/pcapwriter.py

@@ -5,6 +5,7 @@
 import struct
 
 from scat.writers.abstractwriter import AbstractWriter
+from scat.writers.systemd_notify import systemd_notify_watchdog_alive
 
 class PcapWriter(AbstractWriter):
     def __init__(self, filename: str, port_cp: int = 4729, port_up: int = 47290):
@@ -66,6 +67,7 @@ def write_pkt(self, sock_content: bytes, port: int, radio_id: int=0, ts: datetim
             self.ip_id = 0
 
     def write_cp(self, sock_content: bytes, radio_id: int=0, ts: datetime.datetime=datetime.datetime.now()):
+        systemd_notify_watchdog_alive()
         self.write_pkt(sock_content, self.port_cp, radio_id, ts)
 
     def write_up(self, sock_content: bytes, radio_id: int=0, ts: datetime.datetime=datetime.datetime.now()):

src/scat/writers/rawwriter.py

@@ -2,6 +2,7 @@
 # coding: utf8
 
 from scat.writers.abstractwriter import AbstractWriter
+from scat.writers.systemd_notify import systemd_notify_watchdog_alive
 
 class RawWriter(AbstractWriter):
     def __init__(self, fname: str, header: bytes=b'', trailer: bytes=b''):
@@ -13,6 +14,7 @@ def __enter__(self):
         return self
 
     def write_cp(self, sock_content: bytes, radio_id: int=0, ts: None = None):
+        systemd_notify_watchdog_alive()
         self.raw_file.write(sock_content)
 
     def write_up(self, sock_content: bytes, radio_id: int=0, ts: None = None):

src/scat/writers/socketwriter.py

@@ -5,6 +5,7 @@
 import struct
 
 from scat.writers.abstractwriter import AbstractWriter
+from scat.writers.systemd_notify import systemd_notify_watchdog_alive
 
 class SocketWriter(AbstractWriter):
     def __init__(self, base_address: str, port_cp: int = 4729, port_up: int = 47290):
@@ -21,6 +22,7 @@ def __enter__(self):
         return self
 
     def write_cp(self, sock_content: bytes, radio_id: int=0, ts: None = None):
+        systemd_notify_watchdog_alive()
         if radio_id <= 0:
             dest_address = self.base_address
         else:

src/scat/writers/systemd_notify.py

@@ -0,0 +1,4 @@
+import subprocess
+
+def systemd_notify_watchdog_alive():
+    subprocess.run(["systemd-notify", "WATCHDOG=1"], check=True)