avoid installing dependencies for widgets

limbus/widgets/types.py

@@ -5,9 +5,15 @@
 import logging
 import functools
 
-import cv2
+try:
+    # NOTE: we import the cv2 & visdom modules here to avoid having it as a dependency
+    # for the whole project.
+    import cv2
+    import visdom
+except ImportError:
+    pass
+
 import torch
-import visdom
 import kornia
 import numpy as np
 
@@ -163,6 +169,11 @@ class Visdom(Viz):
 
     def __init__(self) -> None:
         super().__init__()
+        try:
+            import visdom
+        except:
+            raise ImportError("To use Visdom as backend install the widgets extras: "
+                              "pip install limbus[widgets]")
         self._vis: Optional[visdom.Visdom] = None
         self._try_init()
 
@@ -305,6 +316,14 @@ def show_text(self, component: Component, title: str, text: str, append: bool =
 class OpenCV(Console):
     """Console visualization backend + openCV for images."""
 
+    def __init__(self) -> None:
+        super().__init__()
+        try:
+            import cv2
+        except:
+            raise ImportError("To use OpenCV as backend install the widgets extras: "
+                              "pip install limbus[widgets]")
+
     @is_enabled
     @set_title
     def show_image(self, component: Component, title: str, image: torch.Tensor):

setup.py

@@ -10,10 +10,8 @@
       install_requires=[
           'torch',
           'numpy',
-          'visdom',
           'typeguard',
           'kornia',
-          'opencv-python'
       ],
       extras_require={
           'dev': [
@@ -30,7 +28,11 @@
           ],
           'components': [
               'limbus-components'
-          ]
+          ],
+          'widgets': [
+              'visdom',
+              'opencv-python',
+            ]
       },
       packages=find_packages(where='.'),
       package_dir={'': '.'},

setup_dev_env.sh

@@ -43,5 +43,5 @@ $conda_bin env create
 source $conda_bin_dir/activate $dev_env_dir/envs/limbus
 
 # install dev requirements
-pip install -e .[dev,components]
+pip install -e .[dev,components,widgets]
 # note that limbus-components is not installed in editable mode