Avoid calling setup.py in the extract_messages command

The setup.py has been deprecated in Python for quite a while, and it has
been generating a lot of warnings. We can avoid it completely, together
with the shell call, by calling the babel functions directly.

I'm also moving the extractor settings from pyproject.toml to the
relevant babel-*.cfg files, to keep everything together.

Signed-off-by: Radomir Dopieralski <openstack@dopieralski.pl>
Change-Id: Ie0616b5f2a96cf8560135e5f6849c737aa9b88d0

babel-django.cfg

@@ -1,3 +1,5 @@
 [python: **.py]
 [django: **/templates/**.html]
 [django: **/templates/**.csv]
+[extractors]
+django = horizon.utils.babel_extract_django:extract_django

babel-djangojs.cfg

@@ -5,3 +5,5 @@
 # /openstack_dashboard/dashboards/XYZ/static which will ensure
 # that plugins are also translated.
 [angular: **/static/**.html]
+[extractors]
+angular = horizon.utils.babel_extract_angular:extract_angular

openstack_dashboard/management/commands/extract_messages.py

@@ -13,10 +13,9 @@
 # limitations under the License.
 
 import os
-from subprocess import call
 
+from babel.messages.frontend import CommandLineInterface
 from django.core.management.base import BaseCommand
-from setuptools.dist import Distribution
 
 
 DOMAINS = ['django', 'djangojs']
@@ -44,17 +43,6 @@ class Command(BaseCommand):
                                   "polluting the source code"))
 
     def handle(self, *args, **options):
-        cmd = ('python setup.py {quiet} extract_messages '
-               '-F babel-{domain}.cfg '
-               '--input-dirs {module} '
-               '-o {potfile}')
-        distribution = Distribution()
-        distribution.parse_config_files(distribution.find_config_files())
-
-        quiet = '-q' if int(options['verbosity']) == 0 else ''
-        if options['check_only']:
-            cmd += " ; rm {potfile}"
-
         for module in options['module']:
             for domain in options['domain']:
                 potfile = '{module}/locale/{domain}.pot'.format(module=module,
@@ -62,6 +50,14 @@ class Command(BaseCommand):
                 if not os.path.exists(potfile):
                     with open(potfile, 'wb') as f:
                         f.write(b'')
-
-                call(cmd.format(module=module, domain=domain, potfile=potfile,
-                                quiet=quiet), shell=True)
+                command = [
+                    'pybabel', 'extract',
+                    '-F', f'babel-{domain}.cfg',
+                    '--input-dirs', module,
+                    '-o', potfile,
+                ]
+                if int(options['verbosity']) == 0:
+                    command.insert(1, '-q')
+                CommandLineInterface().run(command)
+                if options['check_only']:
+                    os.remove(potfile)

pyproject.toml

@@ -36,13 +36,6 @@ classifiers = [
 openstack_dashboard = "openstack_dashboard.utils.config:list_options"
 openstack_dashboard_integration_tests = "openstack_dashboard.test.integration_tests.config:list_opts"
 
-[project.entry-points."babel.extractors"]
-# We use a custom extractor to find translatable strings in AngularJS templates.
-# See https://babel.pocoo.org/en/latest/messages.html#referencing-extraction-methods
-# for details on how this works.
-angular = "horizon.utils.babel_extract_angular:extract_angular"
-django = "horizon.utils.babel_extract_django:extract_django"
-
 [project.urls]
 Homepage = "https://docs.openstack.org/horizon"
 Repository = "https://opendev.org/openstack/horizon/"