Move named url init out of Middleware init

* Middleware classes can be instantiated multiple times in testing. To
  make this a non-issue, move the init code for named urls out of the
  middleware init and into the app init.
* This makes it easier to use other testing facilities, like
  LiveServerTestCase, without having to mock the named url middleware
  init.

awx/main/apps.py

@@ -1,7 +1,40 @@
 from django.apps import AppConfig
 from django.utils.translation import gettext_lazy as _
+from awx.main.utils.named_url_graph import _customize_graph, generate_graph
+from awx.conf import register, fields
 
 
 class MainConfig(AppConfig):
     name = 'awx.main'
     verbose_name = _('Main')
+
+    def load_named_url_feature(self):
+        models = [m for m in self.get_models() if hasattr(m, 'get_absolute_url')]
+        generate_graph(models)
+        _customize_graph()
+        register(
+            'NAMED_URL_FORMATS',
+            field_class=fields.DictField,
+            read_only=True,
+            label=_('Formats of all available named urls'),
+            help_text=_('Read-only list of key-value pairs that shows the standard format of all available named URLs.'),
+            category=_('Named URL'),
+            category_slug='named-url',
+        )
+        register(
+            'NAMED_URL_GRAPH_NODES',
+            field_class=fields.DictField,
+            read_only=True,
+            label=_('List of all named url graph nodes.'),
+            help_text=_(
+                'Read-only list of key-value pairs that exposes named URL graph topology.'
+                ' Use this list to programmatically generate named URLs for resources'
+            ),
+            category=_('Named URL'),
+            category_slug='named-url',
+        )
+
+    def ready(self):
+        super().ready()
+
+        self.load_named_url_feature()

awx/main/middleware.py

@@ -9,18 +9,13 @@ from pathlib import Path
 
 from django.conf import settings
 from django.contrib.auth import logout
-from django.contrib.auth.models import User
 from django.db.migrations.recorder import MigrationRecorder
 from django.db import connection
 from django.shortcuts import redirect
-from django.apps import apps
 from django.utils.deprecation import MiddlewareMixin
-from django.utils.translation import gettext_lazy as _
 from django.urls import reverse, resolve
 
 from awx.main import migrations
-from awx.main.utils.named_url_graph import generate_graph, GraphNode
-from awx.conf import fields, register
 from awx.main.utils.profiling import AWXProfiler
 from awx.main.utils.common import memoize
 
@@ -100,49 +95,7 @@ class DisableLocalAuthMiddleware(MiddlewareMixin):
                 logout(request)
 
 
-def _customize_graph():
-    from awx.main.models import Instance, Schedule, UnifiedJobTemplate
-
-    for model in [Schedule, UnifiedJobTemplate]:
-        if model in settings.NAMED_URL_GRAPH:
-            settings.NAMED_URL_GRAPH[model].remove_bindings()
-            settings.NAMED_URL_GRAPH.pop(model)
-    if User not in settings.NAMED_URL_GRAPH:
-        settings.NAMED_URL_GRAPH[User] = GraphNode(User, ['username'], [])
-        settings.NAMED_URL_GRAPH[User].add_bindings()
-    if Instance not in settings.NAMED_URL_GRAPH:
-        settings.NAMED_URL_GRAPH[Instance] = GraphNode(Instance, ['hostname'], [])
-        settings.NAMED_URL_GRAPH[Instance].add_bindings()
-
-
 class URLModificationMiddleware(MiddlewareMixin):
-    def __init__(self, get_response):
-        models = [m for m in apps.get_app_config('main').get_models() if hasattr(m, 'get_absolute_url')]
-        generate_graph(models)
-        _customize_graph()
-        register(
-            'NAMED_URL_FORMATS',
-            field_class=fields.DictField,
-            read_only=True,
-            label=_('Formats of all available named urls'),
-            help_text=_('Read-only list of key-value pairs that shows the standard format of all available named URLs.'),
-            category=_('Named URL'),
-            category_slug='named-url',
-        )
-        register(
-            'NAMED_URL_GRAPH_NODES',
-            field_class=fields.DictField,
-            read_only=True,
-            label=_('List of all named url graph nodes.'),
-            help_text=_(
-                'Read-only list of key-value pairs that exposes named URL graph topology.'
-                ' Use this list to programmatically generate named URLs for resources'
-            ),
-            category=_('Named URL'),
-            category_slug='named-url',
-        )
-        super().__init__(get_response)
-
     @staticmethod
     def _hijack_for_old_jt_name(node, kwargs, named_url):
         try:

awx/main/tests/functional/test_named_url.py

@@ -1,9 +1,6 @@
 # -*- coding: utf-8 -*-
-from unittest import mock
-
 import pytest
 
-from django.core.exceptions import ImproperlyConfigured
 from django.conf import settings
 
 from awx.api.versioning import reverse
@@ -23,25 +20,6 @@ from awx.main.models import (  # noqa
     User,
     WorkflowJobTemplate,
 )
-from awx.conf import settings_registry
-
-
-def setup_module(module):
-    # In real-world scenario, named url graph structure is populated by __init__
-    # of URLModificationMiddleware. The way Django bootstraps ensures the initialization
-    # will happen *once and only once*, while the number of initialization is uncontrollable
-    # in unit test environment. So it is wrapped by try-except block to mute any
-    # unwanted exceptions.
-    try:
-        URLModificationMiddleware(mock.Mock())
-    except ImproperlyConfigured:
-        pass
-
-
-def teardown_module(module):
-    # settings_registry will be persistent states unless we explicitly clean them up.
-    settings_registry.unregister('NAMED_URL_FORMATS')
-    settings_registry.unregister('NAMED_URL_GRAPH_NODES')
 
 
 @pytest.mark.django_db

awx/main/utils/named_url_graph.py

@@ -5,7 +5,6 @@ from collections import deque
 # Django
 from django.db import models
 from django.conf import settings
-from django.contrib.contenttypes.models import ContentType
 
 
 NAMED_URL_RES_DILIMITER = "++"
@@ -245,6 +244,8 @@ def _generate_configurations(nodes):
 
 
 def _dfs(configuration, model, graph, dead_ends, new_deadends, parents):
+    from django.contrib.contenttypes.models import ContentType
+
     parents.add(model)
     fields, fk_names = configuration[model][0][:], configuration[model][1][:]
     adj_list = []
@@ -306,3 +307,19 @@ def generate_graph(models):
 def reset_counters():
     for node in settings.NAMED_URL_GRAPH.values():
         node.counter = 0
+
+
+def _customize_graph():
+    from django.contrib.auth.models import User
+    from awx.main.models import Instance, Schedule, UnifiedJobTemplate
+
+    for model in [Schedule, UnifiedJobTemplate]:
+        if model in settings.NAMED_URL_GRAPH:
+            settings.NAMED_URL_GRAPH[model].remove_bindings()
+            settings.NAMED_URL_GRAPH.pop(model)
+    if User not in settings.NAMED_URL_GRAPH:
+        settings.NAMED_URL_GRAPH[User] = GraphNode(User, ['username'], [])
+        settings.NAMED_URL_GRAPH[User].add_bindings()
+    if Instance not in settings.NAMED_URL_GRAPH:
+        settings.NAMED_URL_GRAPH[Instance] = GraphNode(Instance, ['hostname'], [])
+        settings.NAMED_URL_GRAPH[Instance].add_bindings()