Drop use of setuptools extension

We were wrapping easy_install's 'install_scripts' and 'develop' methods
to generate a custom WSGI script. This was a replacement of
functionality previously provided by PBR. Unfortunately easy_install is
deprecated for removal at a future date and we don't yet have a modern
equivalent in pip [1]. As such, we need a migration plan for this and it
seems like the old school 'scripts' option is probably it. The main
downside of this is that the shebang isn't updated accordingly, which
means this won't work very well in virtualenvs, but I'm hoping that the
use of '/usr/bin/env' will allow us to work around this. At least in
local testing, it seems like this is the case:

  ❯ virtualenv .venv
  ❯ pip install .
  ❯ cat .venv/bin/gnocchi-api | head -1
  #!/gnocchi/.venv/bin/python

[1] https://discuss.python.org/t/adding-support-for-wsgi-scripts-entrypoint/30905

Signed-off-by: Stephen Finucane <[email protected]>

bin/gnocchi-api

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import sys
+from gnocchi.cli import api
+
+if __name__ == '__main__':
+    sys.exit(api.api())
+else:
+    application = api.wsgi()

setup.cfg

@@ -25,6 +25,9 @@ packages =
 
 include_package_data = true
 
+scripts =
+    bin/gnocchi-api
+
 install_requires =
     numpy>=1.14.0
     iso8601

setup.py

@@ -15,82 +15,8 @@
 # limitations under the License.
 
 import setuptools
-import sys
 
-from setuptools.command import develop
-from setuptools.command import easy_install
-from setuptools.command import install_scripts
-
-
-# NOTE(sileht): We use a template to set the right
-# python version in the sheban
-SCRIPT_TMPL = """
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#    http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-# implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-import sys
-from gnocchi.cli import api
-
-if __name__ == '__main__':
-    sys.exit(api.api())
-else:
-    application = api.wsgi()
-"""
-
-
-PY3 = sys.version_info >= (3,)
-
-
-class local_install_scripts(install_scripts.install_scripts):
-    def run(self):
-        # NOTE(tobias-urdin): Always install_scripts so that we get
-        # gnocchi-api otherwise it's left out when installing with pip.
-        self.no_ep = False
-        install_scripts.install_scripts.run(self)
-        # NOTE(sileht): Build wheel embed custom script as data, and put sheban
-        # in script of the building machine. To workaround that build_scripts
-        # on bdist_whell return '#!python' and then during whl install it's
-        # replaced by the correct interpreter. We do the same here.
-        bs_cmd = self.get_finalized_command('build_scripts')
-        executable = getattr(bs_cmd, 'executable', easy_install.sys_executable)
-        try:
-            script = easy_install.get_script_header(
-                "", executable) + SCRIPT_TMPL
-        except AttributeError:
-            script = easy_install.ScriptWriter.get_header(
-                "", executable) + SCRIPT_TMPL
-        if PY3:
-            script = script.encode('ascii')
-        self.write_script("gnocchi-api", script, 'b')
-
-
-class local_develop(develop.develop):
-    def install_wrapper_scripts(self, dist):
-        develop.develop.install_wrapper_scripts(self, dist)
-        if self.exclude_scripts:
-            return
-        try:
-            script = easy_install.get_script_header("") + SCRIPT_TMPL
-        except AttributeError:
-            script = easy_install.ScriptWriter.get_header("") + SCRIPT_TMPL
-        if PY3:
-            script = script.encode('ascii')
-        self.write_script("gnocchi-api", script, 'b')
-
-
-cmdclass = {
-    'develop': local_develop,
-    'install_scripts': local_install_scripts,
-}
+cmdclass = {}
 
 try:
     from sphinx import setup_command