Structure settings in modules

.github/setup_evap/action.yml

@@ -23,8 +23,10 @@ runs:
       with:
         arguments: "${{ inputs.shell }}"
 
-    - name: Add localsettings
-      run: cp evap/settings_test.py evap/localsettings.py
+    - run: |
+        echo "DJANGO_SETTINGS_MODULE=localsettings" >> "$GITHUB_ENV"
+        ln -s evap/development/cisettings.py localsettings.py
+        ln -s evap/settings/schema.pyi localsettings.pyi
       shell: bash
 
     - name: Create data/ directory

.github/workflows/tests.yml

@@ -69,6 +69,7 @@ jobs:
         with:
           submodules: true
       - uses: DeterminateSystems/nix-installer-action@main
+      - run: echo "DJANGO_SETTINGS_MODULE=evap.development.cisettings" >> "$GITHUB_ENV"
       - run: nix run .#build-dist
       - run: tar tvf dist/*.tar.gz
       - run: unzip -l dist/*.whl
@@ -92,6 +93,8 @@ jobs:
       - run: pip install *.whl
       - name: Check that "evaluation" section appears in help string
         run: python -m evap --help | grep --fixed-strings "[evaluation]"
+        env:
+          DJANGO_SETTINGS_MODULE: evap.development.cisettings
 
   test_frontend:
     name: Test Frontend
@@ -225,28 +228,25 @@ jobs:
           WHEEL=$(echo *.whl)
           pip install $WHEEL[psycopg-binary]
 
+      - run: echo "DJANGO_SETTINGS_MODULE=evap.development.cisettings" >> "$GITHUB_ENV"
       - name: Load test data
         working-directory: deployment
         run: |
           cat <(echo 'from evap.settings import *') ../main/evap/settings_test.py | tee deployment_settings.py
           python -m evap migrate
           python -m evap loaddata test_data
-        env:
-          DJANGO_SETTINGS_MODULE: deployment_settings
       - name: Backup database
         working-directory: deployment
         run: ./update_production.sh backup.json
         env:
           EVAP_OVERRIDE_BACKUP_FILENAME: true
           EVAP_SKIP_UPDATE: true
           EVAP_SKIP_APACHE_STEPS: true
-          DJANGO_SETTINGS_MODULE: deployment_settings
       - name: Reload backup
         working-directory: deployment
         run: echo "yy" | ./load_production_backup.sh backup.json
         env:
           EVAP_SKIP_APACHE_STEPS: true
-          DJANGO_SETTINGS_MODULE: deployment_settings
 
   macos-nix-build:
     runs-on: macos-14

.gitignore

@@ -23,6 +23,8 @@ dist/
 .DS_Store
 thumbs.db
 
+localsettings.py
+localsettings.pyi
 evap/localsettings.py
 evap/static/css/evap.css
 evap/static/css/evap.css.map

evap/__main__.py

@@ -1,16 +1,21 @@
 #!/usr/bin/env python3
 
-import os
+import logging
 import sys
 
 from django.conf import settings
 from django.core.management import execute_from_command_line
 
 
 def main():
-    assert not settings.configured
-    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "evap.settings")
     settings.DATADIR.mkdir(exist_ok=True)
+
+    if settings.TESTING:
+        from typeguard import install_import_hook  # noqa: PLC0415
+
+        install_import_hook(("evap", "tools"))
+        logging.disable()
+
     execute_from_command_line(sys.argv)
 
 

evap/development/cisettings.py

@@ -0,0 +1,10 @@
+from evap.settings import default, dev, local_services, open_id, test  # noqa: TID251
+from evap.settings_resolver import resolve_settings
+
+
+class CiSettings:
+    DEBUG = True
+    SECRET_KEY = "evap-github-actions-secret-key"  # nosec
+
+
+globals().update(resolve_settings([default, open_id, dev, local_services, test, CiSettings]))

evap/development/localsettings.template.py

@@ -1,59 +1,12 @@
 # noqa: N999
 
-from fractions import Fraction
-from pathlib import Path
+from evap.settings import debug_toolbar, default, dev, local_services, open_id, test  # noqa: TID251
+from evap.settings_resolver import resolve_settings
 
-from django.utils.safestring import mark_safe
 
-DATABASES = {
-    "default": {
-        "ENGINE": "django.db.backends.postgresql",
-        "NAME": "evap",
-        "USER": "evap",
-        "PASSWORD": "evap",
-        # Absolute path to use unix domain socket
-        "HOST": Path("./data/").resolve(),
-        "CONN_MAX_AGE": 600,
-    }
-}
+class LocalSettings:
+    DEBUG = True
+    SECRET_KEY = "$SECRET_KEY"  # nosec
 
-REDIS_URL = f"unix://{Path('./data/redis.socket').resolve()}"
 
-CACHES = {
-    "default": {
-        "BACKEND": "django.core.cache.backends.redis.RedisCache",
-        "LOCATION": f"{REDIS_URL}?db=0",
-    },
-    "results": {
-        "BACKEND": "django.core.cache.backends.redis.RedisCache",
-        "LOCATION": f"{REDIS_URL}?db=1",
-        "TIMEOUT": None,  # is always invalidated manually
-    },
-    "sessions": {
-        "BACKEND": "django.core.cache.backends.redis.RedisCache",
-        "LOCATION": f"{REDIS_URL}?db=2",
-    },
-}
-
-# Make this unique, and don't share it with anybody.
-SECRET_KEY = "$SECRET_KEY"  # nosec
-
-# Make apache work when DEBUG == False
-ALLOWED_HOSTS = ["localhost", "127.0.0.1"]
-
-### Evaluation progress rewards
-GLOBAL_EVALUATION_PROGRESS_REWARDS: list[tuple[Fraction, str]] = [
-    (Fraction("0"), "0€"),
-    (Fraction("0.25"), "1.000€"),
-    (Fraction("0.6"), "3.000€"),
-    (Fraction("0.7"), "7.000€"),
-    (Fraction("0.9"), "10.000€"),
-]
-GLOBAL_EVALUATION_PROGRESS_EXCLUDED_COURSE_TYPE_IDS: list[int] = []
-GLOBAL_EVALUATION_PROGRESS_EXCLUDED_EVALUATION_IDS: list[int] = []
-GLOBAL_EVALUATION_PROGRESS_INFO_TEXT = {
-    "de": mark_safe("Deine Teilnahme am Evaluationsprojekt wird helfen. Evaluiere also <b>jetzt</b>!"),
-    "en": mark_safe("Your participation in the evaluation helps, so evaluate <b>now</b>!"),
-}
-# Questionnaires automatically added to exam evaluations
-EXAM_QUESTIONNAIRE_IDS = [111]
+globals().update(resolve_settings([default, local_services, open_id, dev, test, debug_toolbar, LocalSettings]))

evap/evaluation/tests/test_tools.py

@@ -1,3 +1,5 @@
+import graphlib
+from argparse import Namespace
 from unittest.mock import patch
 from uuid import UUID
 
@@ -18,6 +20,7 @@
     inside_transaction,
     is_prefetched,
 )
+from evap.settings_resolver import derived, not_set, required, resolve_settings
 
 
 class TestLanguageMiddleware(WebTest):
@@ -242,3 +245,83 @@ def test_inside_transaction(self):
 
         with transaction.atomic():
             self.assertTrue(inside_transaction())
+
+
+class TestResolveSettings(TestCase):
+    def test_not_set(self):
+        # We don't use the "remove a previous setting" functionality anywhere, but this behavior is the natural composition of layers and not_set
+        self.assertEqual(resolve_settings([Namespace(FOO=42), Namespace(FOO=not_set())]), {})
+        self.assertEqual(resolve_settings([Namespace(FOO=not_set()), Namespace(FOO=42)]), {"FOO": 42})
+
+    def test_key_names(self):
+        # See SettingResolver.iter_settings
+        self.assertEqual(resolve_settings([Namespace(foo=1, _FOO=2, FoO=3)]), {})
+
+    def test_derived(self):
+        self.assertEqual(
+            resolve_settings(
+                [
+                    Namespace(
+                        FOO=1,
+                        BAR=derived(final={"FOO"})(lambda prev, final: final.FOO + 10),
+                    ),
+                    Namespace(
+                        FOO=derived(prev={"FOO"})(lambda prev, final: prev.FOO + 100),
+                        BAR=derived(prev={"BAR"})(lambda prev, final: prev.BAR + 1000),
+                    ),
+                ]
+            ),
+            {
+                "FOO": 101,
+                "BAR": 1111,
+            },
+        )
+
+    def test_cycle(self):
+        with self.assertRaises(graphlib.CycleError):
+            resolve_settings(
+                [
+                    Namespace(
+                        FOO=derived(final={"BAR"})(lambda prev, final: final.BAR),
+                        BAR=derived(final={"FOO"})(lambda prev, final: final.FOO),
+                    ),
+                    Namespace(
+                        FOO=derived(prev={"FOO"})(lambda prev, final: prev.FOO),
+                        BAR=derived(prev={"BAR"})(lambda prev, final: prev.BAR),
+                    ),
+                ]
+            )
+
+    def test_required(self):
+        with self.assertRaises(ValueError):
+            resolve_settings([Namespace(FOO=required())])
+        with self.assertRaises(ValueError):
+            resolve_settings(
+                [Namespace(FOO=required()), Namespace(FOO=42, BAR=derived(prev={"FOO"})(lambda prev, final: prev.FOO))]
+            )
+        self.assertEqual(
+            resolve_settings(
+                [
+                    Namespace(FOO=required()),
+                    Namespace(FOO=42, BAR=derived(final={"FOO"})(lambda prev, final: final.FOO)),
+                ]
+            ),
+            {"FOO": 42, "BAR": 42},
+        )
+
+    def test_derived_final_dependencies(self):
+        # Ensure that derived final dependencies are ordered before in the topological order
+        self.assertEqual(
+            resolve_settings(
+                [
+                    Namespace(FOO=required()),
+                    Namespace(
+                        FOO=42,
+                        BAR=derived(final={"BAZ"})(lambda prev, final: final.BAZ),
+                        BAZ=derived(final={"FOO"})(lambda prev, final: final.FOO),
+                    ),
+                    Namespace(),
+                ]
+            ),
+            {"FOO": 42, "BAR": 42, "BAZ": 42},
+        )

evap/settings/debug_toolbar.py

@@ -0,0 +1,40 @@
+# pylint: disable=unused-argument,invalid-name
+
+from evap.settings_resolver import derived
+
+# Very helpful but eats a lot of performance on sql-heavy pages.
+# Works only with DEBUG = True and Django's development server (so no apache).
+ENABLE_DEBUG_TOOLBAR = False
+
+
+@derived(final={"DEBUG", "ENABLE_DEBUG_TOOLBAR", "TESTING"})
+def REALLY_ENABLE_DEBUG_TOOLBAR(prev, final):
+    return final.ENABLE_DEBUG_TOOLBAR and final.DEBUG and not final.TESTING
+
+
+@derived(prev={"INSTALLED_APPS"}, final={"REALLY_ENABLE_DEBUG_TOOLBAR"})
+def INSTALLED_APPS(prev, final):
+    if final.REALLY_ENABLE_DEBUG_TOOLBAR:
+        return prev.INSTALLED_APPS + ["debug_toolbar"]
+    return prev.INSTALLED_APPS
+
+
+@derived(prev={"MIDDLEWARE"}, final={"REALLY_ENABLE_DEBUG_TOOLBAR"})
+def MIDDLEWARE(prev, final):
+    if final.REALLY_ENABLE_DEBUG_TOOLBAR:
+        return ["debug_toolbar.middleware.DebugToolbarMiddleware"] + prev.MIDDLEWARE
+    return prev.MIDDLEWARE
+
+
+def show_toolbar(request):
+    return True
+
+
+@derived(prev={"DEBUG_TOOLBAR_CONFIG"}, final={"REALLY_ENABLE_DEBUG_TOOLBAR"})
+def DEBUG_TOOLBAR_CONFIG(prev, final):
+    if final.REALLY_ENABLE_DEBUG_TOOLBAR:
+        return {
+            "SHOW_TOOLBAR_CALLBACK": "evap.settings.debug_toolbar.show_toolbar",
+            "JQUERY_URL": "",
+        }
+    return prev.DEBUG_TOOLBAR_CONFIG