Add import error helper

satpy/readers/insat3d_img_l1b_h5.py

@@ -6,7 +6,11 @@
 import dask.array as da
 import numpy as np
 import xarray as xr
-from datatree import DataTree
+
+from satpy.utils import import_error_helper
+
+with import_error_helper("xarray-datatree"):
+    from datatree import DataTree
 
 from satpy.readers.file_handlers import BaseFileHandler
 

satpy/tests/test_utils.py

@@ -30,7 +30,15 @@
 import pytest
 import xarray as xr
 
-from satpy.utils import angle2xyz, get_satpos, lonlat2xyz, proj_units_to_meters, xyz2angle, xyz2lonlat
+from satpy.utils import (
+    angle2xyz,
+    get_satpos,
+    import_error_helper,
+    lonlat2xyz,
+    proj_units_to_meters,
+    xyz2angle,
+    xyz2lonlat,
+)
 
 
 class TestUtils(unittest.TestCase):
@@ -569,3 +577,12 @@ def test_convert_remote_files_to_fsspec_storage_options(open_files):
     _ = convert_remote_files_to_fsspec(filenames, storage_options=storage_options)
 
     open_files.assert_called_once_with(filenames, **storage_options)
+
+
+def test_import_error_helper():
+    """Test the import error helper."""
+    module = "some_crazy_name_for_unknow_dependency_module"
+    with pytest.raises(ImportError) as err:
+        with import_error_helper(module):
+            import unknow_dependency_module  # noqa
+    assert module in str(err)

satpy/utils.py

@@ -25,6 +25,7 @@
 import logging
 import os
 import warnings
+from contextlib import contextmanager
 from typing import Mapping, Optional
 from urllib.parse import urlparse
 
@@ -680,3 +681,12 @@ def _merge_storage_options(storage_options, storage_opt_dict):
         storage_options = storage_opt_dict
 
     return storage_options
+
+
+@contextmanager
+def import_error_helper(dependency_name):
+    """Give more info on an import error."""
+    try:
+        yield
+    except ImportError as err:
+        raise ImportError(err.msg + f" It can be installed with the {dependency_name} package.")