Add BLE retry/backoff for connection timeouts and bump to 0.1.10

fichero_printer/fichero/printer.py

@@ -53,6 +53,8 @@ DELAY_CHUNK_GAP = 0.02       # inter-chunk pacing for BLE throughput
 DELAY_RASTER_SETTLE = 0.50   # wait for printhead after raster transfer
 DELAY_AFTER_FEED = 0.30      # wait after form feed before stop command
 DELAY_NOTIFY_EXTRA = 0.05    # extra wait for trailing BLE notification fragments
+BLE_CONNECT_RETRIES = 3      # retry transient BLE connect failures
+BLE_CONNECT_BACKOFF = 0.7    # base backoff in seconds (linear: n * base)
 
 
 # --- Exceptions ---
@@ -405,17 +407,38 @@ async def connect(
         raise PrinterError(f"Classic Bluetooth connection failed for '{address}'.")
     else:
         addr = address or await find_printer()
-        try:
-            async with BleakClient(addr) as client:
-                pc = PrinterClient(client)
-                await pc.start()
-                yield pc
-        except BleakDBusError as exc:
-            if "br-connection-not-supported" in str(exc).lower():
-                raise PrinterError(
-                    "BLE connection failed (br-connection-not-supported). "
-                    "Try Classic Bluetooth with classic=true and channel=1."
-                ) from exc
-            raise PrinterError(f"BLE connection failed: {exc}") from exc
-        except BleakError as exc:
-            raise PrinterError(f"BLE error: {exc}") from exc
+        def _is_retryable_ble_error(exc: Exception) -> bool:
+            msg = str(exc).lower()
+            return any(token in msg for token in ("timeout", "timed out", "br-connection-timeout"))
+
+        last_exc: Exception | None = None
+        for attempt in range(1, BLE_CONNECT_RETRIES + 1):
+            try:
+                async with BleakClient(addr) as client:
+                    pc = PrinterClient(client)
+                    await pc.start()
+                    yield pc
+                    return
+            except BleakDBusError as exc:
+                msg = str(exc).lower()
+                if "br-connection-not-supported" in msg:
+                    raise PrinterError(
+                        "BLE connection failed (br-connection-not-supported). "
+                        "Try Classic Bluetooth with classic=true and channel=1."
+                    ) from exc
+                last_exc = exc
+                if _is_retryable_ble_error(exc) and attempt < BLE_CONNECT_RETRIES:
+                    await asyncio.sleep(BLE_CONNECT_BACKOFF * attempt)
+                    continue
+                raise PrinterError(f"BLE connection failed: {exc}") from exc
+            except BleakError as exc:
+                last_exc = exc
+                if _is_retryable_ble_error(exc) and attempt < BLE_CONNECT_RETRIES:
+                    await asyncio.sleep(BLE_CONNECT_BACKOFF * attempt)
+                    continue
+                raise PrinterError(f"BLE error: {exc}") from exc
+        if last_exc is not None:
+            raise PrinterError(
+                f"BLE connection failed after {BLE_CONNECT_RETRIES} attempts: {last_exc}"
+            ) from last_exc
+        raise PrinterError("BLE connection failed for unknown reason.")