basic systemd integration

Change-Id: I8525971aea417f6744831acf3effc4436c4e9883
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/22934
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Tested-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

debian/control

@@ -16,6 +16,7 @@ Build-Depends: debhelper (>= 11~),
  python3-psutil (>= 0.4),
  python3-pytest,
  python3-serial,
+ python3-systemd,
  git,
  markdown,
  python3-daemon

secop/server.py

@@ -43,6 +43,11 @@ from secop.errors import ConfigError
 from secop.lib import formatException, get_class, getGeneralConfig, mkthread
 from secop.modules import Attached
 
+try:
+    import systemd.daemon
+except ImportError:
+    systemd = None
+
 
 
 class Server:
@@ -102,6 +107,8 @@ class Server:
         while self._restart:
             self._restart = False
             try:
+                if systemd:
+                    systemd.daemon.notify("STATUS=initializing")
                 self._processCfg()
             except Exception:
                 print(formatException(verbose=True))
@@ -112,6 +119,8 @@ class Server:
             for ifname, ifobj in self.interfaces.items():
                 self.log.debug('starting thread for interface %r' % ifname)
                 threads.append((ifname, mkthread(ifobj.serve_forever)))
+            if systemd:
+                systemd.daemon.notify("READY=1\nSTATUS=accepting requests")
             for ifname, t in threads:
                 t.join()
                 self.log.debug('thread for %r died' % ifname)