proper logging, add signal handler for graceful termination

feeder.py

@@ -1,4 +1,6 @@
 import sys
+import signal
+import logging
 from os.path import expanduser
 sys.path.append(expanduser('~'))
 import socket
@@ -20,6 +22,9 @@ Usage:
         python feeder.py uri [device] [instrument]
 """
 
+logging.basicConfig(filename='logfile.log', filemode='w', level=logging.INFO,
+                    format='%(asctime)s %(levelname)s %(message)s')
+
 
 def main(dbname=None, access='write'):
     # egen = EventStream(ScanReply(), ScanStream(), n=NicosStream('localhost:14002'))
@@ -42,14 +47,21 @@ def main(dbname=None, access='write'):
                 port = fm.info.get(ins, {}).get(service, {})
                 if port:
                     uri = f'{host}:{port}'
-                    print('CREATE', uri, ins, cfginfo.get((ins, service)))
+                    logging.info('CREATE %s %s %s', uri, ins, cfginfo.get((ins, service)))
                     TrySecopConnect(uri)
                     db.set_instrument(uri, ins)
 
     event_map = {'value': db.add_float, 'error': db.add_error, 'stream': db.add_stream}
 
+    running = [True]
+
+    def handler(self, num, frame):
+        running.clear()
+
+    signal.signal(signal.SIGTERM, handler)
+
     try:
-        while 1:
+        while running:
             for kind, *args in egen.get_events():
                 event_map[kind](*args)
             db.flush()
@@ -57,6 +69,7 @@ def main(dbname=None, access='write'):
         for kind, *args in egen.finish():
             event_map[kind](*args)
         db.disconnect()
+        logging.info('gracefully finished')
 
 
 if len(sys.argv) >= 3: