Replace pkg_resources with importlib.metadata for entry points (closes #225)

climix/metadata.py

@@ -9,10 +9,10 @@ import logging
 import os
 import re
 import string
+import sys
 from typing import Any, List, Mapping, Optional, Union
 
 import iris
-import pkg_resources
 import xdg.BaseDirectory
 import yaml
 
@@ -20,6 +20,13 @@ from .index import Index
 from .period import PeriodSpecification
 
 
+if sys.version_info[:2] >= (3, 10):
+    # pylint: disable=no-name-in-module
+    from importlib.metadata import entry_points
+else:
+    from importlib_metadata import entry_points
+
+
 @dataclass
 class CellMethod:
     name: str
@@ -355,9 +362,7 @@ class IndexCatalog:
 
 def build_index_function(spec):
     name = spec.name
-    candidates = list(
-        pkg_resources.iter_entry_points("climix.index_functions", name=name)
-    )
+    candidates = list(entry_points(group="climix.index_functions", name=name))
     if len(candidates) == 0:
         raise ValueError(f"No implementation found for index_function <{name}>")
     elif len(candidates) > 1:

setup.py

@@ -36,6 +36,7 @@ setuptools.setup(
         "dask>=2.4.0",
         "dask-jobqueue",
         "distributed>=2.4.0",
+        'importlib_metadata>=4.4; python_version < "2.10"',
         "numpy",
         "pyxdg",
         "PyYAML",