sync controller database to disk and load it on start

src/capport/comm/hub.py

@@ -265,9 +265,6 @@ class ControllerConn:
 
 
 class HubApplication:
-    def is_controller(self) -> bool:
-        return False
-
     async def new_peer(self, *, peer_id: uuid.UUID) -> None:
         _logger.info(f"New peer {peer_id}")
 
@@ -287,13 +284,18 @@ class HubApplication:
 
 
 class Hub:
-    def __init__(self, config: Config, app: HubApplication) -> None:
+    def __init__(self, config: Config, app: HubApplication, *, is_controller: bool) -> None:
         self._config = config
         self._instance_id = uuid.uuid4()
         self._hostname = socket.getfqdn()
-        self.database = capport.database.Database()
         self._app = app
-        self._is_controller = bool(app.is_controller())
+        self._is_controller = is_controller
+        state_filename: typing.Optional[str]
+        if is_controller:
+            state_filename = 'capport.state'
+        else:
+            state_filename = None
+        self.database = capport.database.Database(state_filename=state_filename)
         self._anon_context = ssl.SSLContext()
         # python ssl doesn't support setting tls1.3 ciphers yet, so make sure we stay on 1.2 for now to enable anon
         self._anon_context.minimum_version = ssl.TLSVersion.TLSv1_2
@@ -324,6 +326,7 @@ class Hub:
 
     async def run(self, *, task_status=trio.TASK_STATUS_IGNORED):
         async with trio.open_nursery() as nursery:
+            await nursery.start(self.database.run)
             if self._is_controller:
                 await nursery.start(self._listen)
 
@@ -412,12 +415,12 @@ class Hub:
             pass
         elif isinstance(variant, capport.comm.message.MacStates):
             await self._app.received_mac_state(from_peer_id=peer_id, states=variant)
-            pu = capport.database.PendingUpdates()
-            for state in variant.states:
-                self.database.received_mac_state(state, pending_updates=pu)
-            if pu.macs:
+            async with self.database.make_changes() as pu:
+                for state in variant.states:
+                    pu.received_mac_state(state)
+            if pu:
                 # re-broadcast all received updates to all peers
-                await self.broadcast(*pu.serialize(), exclude=peer_id)
+                await self.broadcast(*pu.serialized, exclude=peer_id)
                 await self._app.mac_states_changed(from_peer_id=peer_id, pending_updates=pu)
         else:
             await self._app.received_unknown_message(from_peer_id=peer_id, msg=msg)