Added file locking to avoid db contention

RobottasSignalr.py

@@ -7,6 +7,8 @@ import time
 import sqlite3
 import sys
 
+from contextlib import closing
+from filelock import Timeout, FileLock
 from fastf1.signalr_aio import Connection
 
 import fastf1
@@ -85,7 +87,8 @@ class SignalRClient:
                        "SessionData", "LapCount"]
 
         self.debug = debug
-        self._db_is_open = False
+        self.messages_db = 'messages.db'
+        self.messages_lock = FileLock('messages.lock')
         self.filename = filename
         self.filemode = filemode
         self.timeout = timeout
@@ -97,6 +100,7 @@ class SignalRClient:
                 stream=sys.stderr
             )
             self.logger = logging.getLogger('SignalR')
+            self.logger.warning("Created logger for SignalR")
         else:
             self.logger = logger
 
@@ -104,23 +108,15 @@ class SignalRClient:
         self._t_last_message = None
 
     def _to_file(self, msg):
-        """
-        self._output_file.write(msg + '\n')
-        self._output_file.flush()
-        """
-        #print(msg)
-        con = sqlite3.connect('messages.db')
-
         try:
-            with con:
-                self._db_is_open = True
-                con.execute("insert into messages (message) values(?)", (msg,))
-            con.close()
-            self.db_is_open = False
+            with self.messages_lock:
+                with closing(sqlite3.connect(self.messages_db)) as con:
+                    with closing(con.cursor()) as cur:
+                        #self.logger.warning("about to log: " + msg)
+                        cur.execute("insert into messages (message) values(?)", (msg,))
+                        con.commit()
         except:
-            if con is not None:
-                con.close()
-            self._db_is_open = False
+            print(f'Error writing message to db.')
 
     async def _on_do_nothing(self, msg):
         # just do nothing with the message; intended for debug mode where some
@@ -196,8 +192,6 @@ class SignalRClient:
         await asyncio.gather(asyncio.ensure_future(self._supervise()),
                              asyncio.ensure_future(self._run()))
         #self._output_file.close()
-        while(self._db_is_open):
-            asyncio.sleep(1)
         self.logger.warning("Exiting...")
 
     def start(self):