Add import error details for optional dependencies (#606)

Author: rickwierenga

pylabrobot/audio/audio.py

@@ -9,15 +9,18 @@
   from IPython.display import Audio, display
 
   USE_AUDIO = True
-except ImportError:
+except ImportError as e:
   USE_AUDIO = False
+  _AUDIO_IMPORT_ERROR = e
 
 
 def _audio_check(func):
   @functools.wraps(func)
   def wrapper(*args, **kwargs):
     if not USE_AUDIO:
-      return
+      raise RuntimeError(
+        f"Audio functionality requires IPython.display. Import error: {_AUDIO_IMPORT_ERROR}"
+      )
     return func(*args, **kwargs)
 
   return wrapper

pylabrobot/io/ftdi.py

@@ -9,8 +9,9 @@
   from pylibftdi import Device
 
   HAS_PYLIBFTDI = True
-except ImportError:
+except ImportError as e:
   HAS_PYLIBFTDI = False
+  _FTDI_IMPORT_ERROR = e
 
 from pylabrobot.io.capture import CaptureReader, Command, capturer, get_capture_or_validation_active
 from pylabrobot.io.errors import ValidationError
@@ -38,7 +39,7 @@ def __init__(self, device_id: Optional[str] = None):
 
   async def setup(self):
     if not HAS_PYLIBFTDI:
-      raise RuntimeError("pylibftdi not installed.")
+      raise RuntimeError(f"pylibftdi not installed. Import error: {_FTDI_IMPORT_ERROR}")
     self._dev.open()
     self._executor = ThreadPoolExecutor(max_workers=1)
 

pylabrobot/io/hid.py

@@ -12,8 +12,9 @@
   import hid  # type: ignore
 
   USE_HID = True
-except ImportError:
+except ImportError as e:
   USE_HID = False
+  _HID_IMPORT_ERROR = e
 
 
 logger = logging.getLogger(__name__)
@@ -40,7 +41,9 @@ def __init__(self, vid=0x03EB, pid=0x2023, serial_number: Optional[str] = None):
 
   async def setup(self):
     if not USE_HID:
-      raise RuntimeError("This backend requires the `hid` package to be installed")
+      raise RuntimeError(
+        f"This backend requires the `hid` package to be installed. Import error: {_HID_IMPORT_ERROR}"
+      )
     self.device = hid.Device(vid=self.vid, pid=self.pid, serial=self.serial_number)
     self._executor = ThreadPoolExecutor(max_workers=1)
     logger.log(LOG_LEVEL_IO, "Opened HID device %s", self._unique_id)

pylabrobot/io/serial.py

@@ -11,8 +11,9 @@
   import serial
 
   HAS_SERIAL = True
-except ImportError:
+except ImportError as e:
   HAS_SERIAL = False
+  _SERIAL_IMPORT_ERROR = e
 
 from pylabrobot.io.capture import CaptureReader, Command, capturer, get_capture_or_validation_active
 from pylabrobot.io.validation_utils import LOG_LEVEL_IO, align_sequences
@@ -63,7 +64,7 @@ def port(self) -> str:
 
   async def setup(self):
     if not HAS_SERIAL:
-      raise RuntimeError("pyserial not installed.")
+      raise RuntimeError(f"pyserial not installed. Import error: {_SERIAL_IMPORT_ERROR}")
     loop = asyncio.get_running_loop()
     self._executor = ThreadPoolExecutor(max_workers=1)
 

pylabrobot/liquid_handling/backends/http.py

@@ -10,8 +10,9 @@
   import requests
 
   HAS_REQUESTS = True
-except ImportError:
+except ImportError as e:
   HAS_REQUESTS = False
+  _REQUESTS_IMPORT_ERROR = e
 
 
 class HTTPBackend(SerializingBackend):
@@ -44,7 +45,9 @@ def __init__(
     """
 
     if not HAS_REQUESTS:
-      raise RuntimeError("The http backend requires the requests module.")
+      raise RuntimeError(
+        f"The http backend requires the requests module. Import error: {_REQUESTS_IMPORT_ERROR}"
+      )
 
     super().__init__(num_channels=num_channels)
     self.session: Optional[requests.Session] = None

pylabrobot/liquid_handling/backends/opentrons_backend.py

@@ -43,8 +43,9 @@
     from requests import HTTPError
 
     USE_OT = True
-  except ImportError:
+  except ImportError as e:
     USE_OT = False
+    _OT_IMPORT_ERROR = e
 else:
   USE_OT = False
 
@@ -79,6 +80,7 @@ def __init__(self, host: str, port: int = 31950):
     if not USE_OT:
       raise RuntimeError(
         "Opentrons is not installed. Please run pip install pylabrobot[opentrons]."
+        f" Import error: {_OT_IMPORT_ERROR}."
         " Only supported on Python 3.10 and below."
       )
 

pylabrobot/liquid_handling/backends/websocket.py

@@ -12,8 +12,9 @@
   import websockets.legacy.server
 
   HAS_WEBSOCKETS = True
-except ImportError:
+except ImportError as e:
   HAS_WEBSOCKETS = False
+  _WEBSOCKETS_IMPORT_ERROR = e
 
 from pylabrobot.__version__ import STANDARD_FORM_JSON_VERSION
 from pylabrobot.liquid_handling.backends.serializing_backend import (
@@ -46,7 +47,9 @@ def __init__(
     """
 
     if not HAS_WEBSOCKETS:
-      raise RuntimeError("The WebSocketBackend requires websockets to be installed.")
+      raise RuntimeError(
+        f"The WebSocketBackend requires websockets to be installed. Import error: {_WEBSOCKETS_IMPORT_ERROR}"
+      )
 
     super().__init__(num_channels=num_channels)
     self._websocket: Optional["websockets.legacy.server.WebSocketServerProtocol"] = None
@@ -252,7 +255,9 @@ async def setup(self):
     """Start the websocket server. This will run in a separate thread."""
 
     if not HAS_WEBSOCKETS:
-      raise RuntimeError("The WebSocketBackend requires websockets to be installed.")
+      raise RuntimeError(
+        f"The WebSocketBackend requires websockets to be installed. Import error: {_WEBSOCKETS_IMPORT_ERROR}"
+      )
 
     async def run_server():
       self._stop_ = self.loop.create_future()

pylabrobot/plate_reading/biotek_backend.py

@@ -9,25 +9,31 @@
 
 try:
   import cv2  # type: ignore
-except ImportError:
+
+  CV2_AVAILABLE = True
+except ImportError as e:
   cv2 = None  # type: ignore
+  CV2_AVAILABLE = False
+  _CV2_IMPORT_ERROR = e
 
 from pylabrobot.resources.plate import Plate
 
 try:
   import numpy as np  # type: ignore
 
   USE_NUMPY = True
-except ImportError:
+except ImportError as e:
   USE_NUMPY = False
+  _NUMPY_IMPORT_ERROR = e
 
 try:
   import PySpin  # type: ignore
 
   # can be downloaded from https://www.teledynevisionsolutions.com/products/spinnaker-sdk/
   USE_PYSPIN = True
-except ImportError:
+except ImportError as e:
   USE_PYSPIN = False
+  _PYSPIN_IMPORT_ERROR = e
 
 from pylabrobot.io.ftdi import FTDI
 from pylabrobot.plate_reading.backend import ImageReaderBackend
@@ -149,7 +155,10 @@ async def setup(self, use_cam: bool = False) -> None:
 
     if use_cam:
       if not USE_PYSPIN:
-        raise RuntimeError("PySpin is not installed. Please follow the imaging setup instructions.")
+        raise RuntimeError(
+          "PySpin is not installed. Please follow the imaging setup instructions. "
+          f"Import error: {_PYSPIN_IMPORT_ERROR}"
+        )
       if self.imaging_config is None:
         raise RuntimeError("Imaging configuration is not set.")
 
@@ -866,7 +875,10 @@ async def auto_focus(self, timeout: float = 30):
       raise RuntimeError("Row and column not set. Run select() first.")
     if not USE_NUMPY:
       # This is strange, because Spinnaker requires numpy
-      raise RuntimeError("numpy is not installed. See Cytation5 installation instructions.")
+      raise RuntimeError(
+        "numpy is not installed. See Cytation5 installation instructions. "
+        f"Import error: {_NUMPY_IMPORT_ERROR}"
+      )
 
     # objective function: variance of laplacian
     async def evaluate_focus(focus_value):
@@ -882,8 +894,10 @@ async def evaluate_focus(focus_value):
       )
       image = images[0]  # self.capture returns List now
 
-      if cv2 is None:
-        raise RuntimeError("cv2 needs to be installed for auto focus")
+      if not CV2_AVAILABLE:
+        raise RuntimeError(
+          f"cv2 needs to be installed for auto focus. Import error: {_CV2_IMPORT_ERROR}"
+        )
 
       # NVMG: Normalized Variance of the Gradient Magnitude
       # Chat invented this i think

pylabrobot/pumps/agrowpumps/agrowdosepump_backend.py

@@ -6,8 +6,11 @@
 
 try:
   from pymodbus.client import AsyncModbusSerialClient  # type: ignore
-except ImportError:
+
+  _MODBUS_IMPORT_ERROR = None
+except ImportError as e:
   AsyncModbusSerialClient = None  # type: ignore
+  _MODBUS_IMPORT_ERROR = e
 
 from pylabrobot.pumps.backend import PumpArrayBackend
 
@@ -117,7 +120,10 @@ async def setup(self):
 
   async def _setup_modbus(self):
     if AsyncModbusSerialClient is None:
-      raise RuntimeError("pymodbus is not installed. Please install it with 'pip install pymodbus'")
+      raise RuntimeError(
+        "pymodbus is not installed. Please install it with 'pip install pymodbus'."
+        f" Import error: {_MODBUS_IMPORT_ERROR}"
+      )
     self._modbus = AsyncModbusSerialClient(
       port=self.port,
       baudrate=115200,

pylabrobot/resources/opentrons/load.py

@@ -6,8 +6,9 @@
   import opentrons_shared_data.labware
 
   USE_OT = True
-except ImportError:
+except ImportError as e:
   USE_OT = False
+  _OT_IMPORT_ERROR = e
 
 from pylabrobot.resources.coordinate import Coordinate
 from pylabrobot.resources.plate import Plate
@@ -35,7 +36,9 @@ def ot_definition_to_resource(
 
   if not USE_OT:
     raise ImportError(
-      "opentrons_shared_data is not installed. " "run `pip install opentrons_shared_data`"
+      "opentrons_shared_data is not installed. "
+      f"Import error: {_OT_IMPORT_ERROR}. "
+      "run `pip install opentrons_shared_data`"
     )
 
   display_category = data["metadata"]["displayCategory"]