Try retrying operations in BLE

companion/bluetooth.py

@@ -5,8 +5,8 @@ from able.filters import ServiceUUIDFilter
 from kivy.logger import Logger
 
 _UART_SERVICE_UUID = "6e400001-b5a3-f393-e0a9-e50e24dcca9e"
-_UART_SERVICE_TX_UUID = "6e400002"
-_UART_SERVICE_RX_UUID = "6e400003"
+_UART_SERVICE_TX_UUID = "6e400002-b5a3-f393-e0a9-e50e24dcca9e"
+_UART_SERVICE_RX_UUID = "6e400003-b5a3-f393-e0a9-e50e24dcca9e"
 
 
 class MynitBluetooth(BluetoothDispatcher):
@@ -18,6 +18,7 @@ class MynitBluetooth(BluetoothDispatcher):
         self._available_devices = set()
         self._device = None
         self._characteristics = None, None
+        self._error_count = 0
 
         Logger.info("Starting BLE scanning")
 #        self.start_scan(filters=[ServiceUUIDFilter(_UART_SERVICE_UUID)])
@@ -38,7 +39,9 @@ class MynitBluetooth(BluetoothDispatcher):
 
     def on_scan_completed(self):
         if self._device:
-            # FIXME Add retries
+            self._error_count = 0
+            self.close_gatt()
+            self.gatt.refresh()
             self.connect_gatt(self._device)
 
     def on_connection_state_change(self, status, state):
@@ -49,15 +52,28 @@ class MynitBluetooth(BluetoothDispatcher):
             self.discover_services()
         else:
             Logger.warning("Connection failed, disconnecting and resetting")
-            self.close_gatt()
-            self._characteristics = None, None
-            self._device = None
-            self.start_scan()
+            self._error_count += 1
+            if self._error_count <= 2:
+                self.connect_gatt(self._device)
+            elif self._error_count <= 3:
+                self.close_gatt()
+                self.connect_gatt(self._device)
+            else:
+                self._characteristics = None, None
+                self._device = None
+                self._error_count = 0
+                self.start_scan()
 
     def on_services(self, status, services):
         Logger.info("Services discovered")
         self._characteristics = (services.search(_UART_SERVICE_TX_UUID), services.search(_UART_SERVICE_RX_UUID))
-        self.enable_notifications(self._characteristics[1])
+        Logger.info(self._characteristics)
+        if None in self._characteristics:
+            Logger.warning("UART services not yet found, retrying")
+            self.discover_services()
+        else:
+            Logger.info("UART services found, enabling notifications")
+            self.enable_notifications(self._characteristics[1])
 
     def on_characteristic_changed(self, characteristic):
         Logger.info("Data received")