drop usage of pkg_resource for newer python compat

pkg_resources comes from setuptools and not the python stdlib. Starting
with python 3.12 and newer, setuptools won't automatically be installed
into virtualenvs so the lack of a direct dependency will result in an
error. Further more setuptools has deprecated pkg_resources and intends
to remove it so adding a dependency would just be a band aid. The python
stdlib has added a replacement for how sushy uses pkg_resources starting
with python 3.9 and newer. Since sushy supports python 3.8 and newer we
must support using the backport package.

Depends-on: https://review.opendev.org/c/openstack/requirements/+/925306
Change-Id: I83719e368f8f7d39963c29c0013f512d1883a8dc

requirements.txt

@@ -10,3 +10,4 @@ pbr!=2.1.0,>=2.0.0 # Apache-2.0
 requests>=2.14.2 # Apache-2.0
 python-dateutil>=2.7.0 # BSD
 stevedore>=1.29.0 # Apache-2.0
+importlib_resources>=1.3; python_version<'3.9' # Apache-2.0

sushy/main.py

@@ -16,7 +16,14 @@ import collections
 import logging
 import os
 
-import pkg_resources
+try:
+    from importlib import resources
+
+    if not hasattr(resources, "files"):
+        import importlib_resources as resources
+except ImportError:
+    import importlib_resources as resources
+
 import requests
 
 from sushy import auth as sushy_auth
@@ -41,7 +48,7 @@ from sushy import utils
 
 LOG = logging.getLogger(__name__)
 
-STANDARD_REGISTRY_PATH = 'standard_registries/'
+STANDARD_REGISTRY_PATH = 'standard_registries'
 
 
 class ProtocolFeaturesSupportedField(base.CompositeField):
@@ -568,18 +575,17 @@ class Sushy(base.ResourceBase):
         :returns: list of MessageRegistry
         """
 
-        message_registries = []
-        resource_package_name = __name__
-        for json_file in pkg_resources.resource_listdir(
-                resource_package_name, STANDARD_REGISTRY_PATH):
-            # Not using path.join according to pkg_resources docs
-            mes_reg = message_registry.MessageRegistry(
-                None, STANDARD_REGISTRY_PATH + json_file,
-                reader=base.JsonPackagedFileReader(
-                    resource_package_name))
-            message_registries.append(mes_reg)
-
-        return message_registries
+        return [
+            message_registry.MessageRegistry(
+                None,
+                os.path.join(STANDARD_REGISTRY_PATH, json_file.name),
+                reader=base.JsonPackagedFileReader(__package__),
+            )
+            for json_file in resources.files(__package__)
+            .joinpath(STANDARD_REGISTRY_PATH)
+            .iterdir()
+            if json_file.is_file()
+        ]
 
     @property
     @utils.cache_it

sushy/resources/base.py

@@ -22,7 +22,12 @@ import json
 import logging
 import zipfile
 
-import pkg_resources
+try:
+    from importlib import resources
+    if not hasattr(resources, 'files'):
+        import importlib_resources as resources
+except ImportError:
+    import importlib_resources as resources
 
 from sushy import exceptions
 from sushy.resources import constants
@@ -486,9 +491,9 @@ class JsonPackagedFileReader(AbstractDataReader):
     def get_data(self):
         """Gets JSON file from packaged file denoted by path"""
 
-        with pkg_resources.resource_stream(self._resource_package_name,
-                                           self._path) as resource:
-            json_data = json.loads(resource.read().decode(encoding='utf-8'))
+        ref = resources.files(self._resource_package_name).joinpath(self._path)
+        with ref.open(encoding='utf-8') as fp:
+            json_data = json.load(fp)
             return FieldData(None, None, json_data)