only read/write if file specified in config

FreeDMR-SAMPLE.cfg

@@ -36,6 +36,7 @@ PEER_URL: https://www.radioid.net/static/rptrs.json
 SUBSCRIBER_URL: https://www.radioid.net/static/users.json
 TGID_URL: http://downloads.freedmr.uk/downloads/talkgroup_ids.json
 STALE_DAYS: 7
+SUB_MAP_FILE:
 
 [MYSQL]
 USE_MYSQL: False

bridge_master.py

@@ -417,6 +417,7 @@ def SubMapTrimmer():
     for _remove in _remove_list:
         SUB_MAP.pop(_remove)
     
+    if CONFIG['ALIASES']['SUB_MAP_FILE']:
         subMapWrite()
  
     
@@ -2610,6 +2611,7 @@ if __name__ == '__main__':
         hblink_handler(_signal, _frame)
         logger.info('(GLOBAL) SHUTDOWN: ALL SYSTEM HANDLERS EXECUTED - STOPPING REACTOR')
         reactor.stop()
+        if CONFIG['ALIASES']['SUB_MAP_FILE']:
             subMapWrite()
 
     # Set signal handers so that we can gracefully exit if need be
@@ -2635,6 +2637,7 @@ if __name__ == '__main__':
     #SUB_MAP = {bytes_3(73578):('REP-1',1,time())}
     SUB_MAP = {}
     
+    if CONFIG['ALIASES']['SUB_MAP_FILE']:
         try:
             with open(CONFIG['ALIASES']['SUB_MAP_FILE']) as _json_file:
                 SUB_MAP = json.load(_json_file)

docker-configs/docker-compose_install.sh

@@ -85,6 +85,7 @@ PEER_URL: https://www.radioid.net/static/rptrs.json
 SUBSCRIBER_URL: http://downloads.freedmr.uk/downloads/local_subscriber_ids.json
 TGID_URL: TGID_URL: http://downloads.freedmr.uk/downloads/talkgroup_ids.json
 STALE_DAYS: 7
+SUB_MAP_FILE:
 
 [MYSQL]
 USE_MYSQL: False