bugfix/SK-850 | Sets client status to online in database when client …

…connects (#606)

* Sets client status to online in database when client connects. Also clean up status of previously connected clients on startup.

fedn/network/combiner/combiner.py

@@ -65,7 +65,6 @@ def __init__(self, config):
         # Client queues
         self.clients = {}
 
-        self.modelservice = ModelService()
 
         # Validate combiner name
         match = re.search(VALID_NAME_REGEX, config["name"])
@@ -122,6 +121,17 @@ def __init__(self, config):
         self.repository = Repository(announce_config["storage"]["storage_config"])
 
         self.statestore = MongoStateStore(announce_config["statestore"]["network_id"], announce_config["statestore"]["mongo_config"])
+
+        # Fetch all clients previously connected to the combiner
+        # If a client and a combiner goes down at the same time,
+        # the client will be stuck listed as "online" in the statestore.
+        # Set the status to offline for previous clients.
+        previous_clients = self.statestore.clients.find({"combiner": config["name"]})
+        for client in previous_clients:
+            self.statestore.set_client({"name": client["name"], "status": "offline"})
+
+        self.modelservice = ModelService()
+
         # Create gRPC server
         self.server = Server(self, self.modelservice, grpc_config)
 
@@ -600,6 +610,10 @@ def TaskStream(self, response, context):
 
         self._send_status(status)
 
+        # Set client status to online
+        self.clients[client.name]["status"] = "online"
+        self.statestore.set_client({"name": client.name, "status": "online"})
+
         # Keep track of the time context has been active
         start_time = time.time()
         while context.is_active():