[FR] Add Feature flags (#4982)

* make currency choices independend

* Remove check for field, just try to get rid of it

* Add IF EXISTS to avoid error (works in postgres)

* Look for operational error, not programming error

* Use variants, depending on errors caused

* [FR] Add Feature flags
Fixes #4965

* Add option to define custom flags

* Revert "make currency choices independend"

This reverts commit ab84a7ff83.

* try fixing mysql

* more safeguards

* fix executioner call

* a fck

* use migrations. syntax

* and another round for mysql

* revert print change

* use UTC for datetime

* Update part.migrations.0112

- Add custom migration class which handles errors

* Add unit test for migration

- Ensure that the new fields are added to the model

* Update reference to PR

* fix ruleset for missing_models

* fix ruleset for flags_flagstate

* add API endpoints for flags

* add tests for new API endpoints

* fix tests

* fix merge

* fix tests

---------

Co-authored-by: martin <martin@iggland.com>
Co-authored-by: Oliver Walters <oliver.henry.walters@gmail.com>

InvenTree/InvenTree/settings.py

@@ -234,6 +234,7 @@ INSTALLED_APPS = [
     'formtools',                            # Form wizard tools
     'dbbackup',                             # Backups - django-dbbackup
     'taggit',                               # Tagging
+    'flags',                                # Flagging - django-flags
 
     'allauth',                              # Base app for SSO
     'allauth.account',                      # Extend user with accounts
@@ -944,3 +945,23 @@ if DEBUG:
 
 logger.info(f"MEDIA_ROOT: '{MEDIA_ROOT}'")
 logger.info(f"STATIC_ROOT: '{STATIC_ROOT}'")
+
+# Flags
+FLAGS = {
+    'EXPERIMENTAL': [
+        {'condition': 'boolean', 'value': DEBUG},
+        {'condition': 'parameter', 'value': 'experimental='},
+    ],  # Should experimental features be turned on?
+    'NEXT_GEN': [
+        {'condition': 'parameter', 'value': 'ngen='},
+    ],  # Should next-gen features be turned on?
+}
+
+# Get custom flags from environment/yaml
+CUSTOM_FLAGS = get_setting('INVENTREE_FLAGS', 'flags', None, typecast=dict)
+if CUSTOM_FLAGS:
+    if not isinstance(CUSTOM_FLAGS, dict):
+        logger.error(f"Invalid custom flags, must be valid dict: {CUSTOM_FLAGS}")
+    else:
+        logger.info(f"Custom flags: {CUSTOM_FLAGS}")
+        FLAGS.update(CUSTOM_FLAGS)

InvenTree/common/api.py

@@ -2,6 +2,7 @@
 
 import json
 
+from django.conf import settings
 from django.http.response import HttpResponse
 from django.urls import include, path, re_path
 from django.utils.decorators import method_decorator
@@ -480,6 +481,29 @@ class ProjectCodeDetail(RetrieveUpdateDestroyAPI):
     permission_classes = [permissions.IsAuthenticated, IsStaffOrReadOnly]
 
 
+class FlagList(ListAPI):
+    """List view for feature flags."""
+
+    queryset = settings.FLAGS
+    serializer_class = common.serializers.FlagSerializer
+    permission_classes = [permissions.AllowAny, ]
+
+
+class FlagDetail(RetrieveAPI):
+    """Detail view for an individual feature flag."""
+
+    serializer_class = common.serializers.FlagSerializer
+    permission_classes = [permissions.AllowAny, ]
+
+    def get_object(self):
+        """Attempt to find a config object with the provided key."""
+        key = self.kwargs['key']
+        value = settings.FLAGS.get(key, None)
+        if not value:
+            raise NotFound()
+        return {key: value}
+
+
 settings_api_urls = [
     # User settings
     re_path(r'^user/', include([
@@ -552,6 +576,11 @@ common_api_urls = [
         re_path(r'^.*$', NewsFeedEntryList.as_view(), name='api-news-list'),
     ])),
 
+    # Flags
+    path('flags/', include([
+        path('<str:key>/', FlagDetail.as_view(), name='api-flag-detail'),
+        re_path(r'^.*$', FlagList.as_view(), name='api-flag-list'),
+    ])),
 ]
 
 admin_api_urls = [

InvenTree/common/serializers.py

@@ -1,7 +1,9 @@
 """JSON serializers for common components."""
 
+
 from django.urls import reverse
 
+from flags.state import flag_state
 from rest_framework import serializers
 
 from common.models import (InvenTreeSetting, InvenTreeUserSetting,
@@ -269,3 +271,19 @@ class ProjectCodeSerializer(InvenTreeModelSerializer):
             'code',
             'description'
         ]
+
+
+class FlagSerializer(serializers.Serializer):
+    """Serializer for feature flags."""
+
+    def to_representation(self, instance):
+        """Return the configuration data as a dictionary."""
+        request = self.context.get('request')
+        if not isinstance(instance, str):
+            instance = list(instance.keys())[0]
+        data = {'key': instance, 'state': flag_state(instance, request=request)}
+
+        if request and request.user.is_superuser:
+            data['conditions'] = self.instance[instance]
+
+        return data

InvenTree/common/tests.py

@@ -875,6 +875,43 @@ class CommonTest(InvenTreeAPITestCase):
         self.user.is_superuser = False
         self.user.save()
 
+    def test_flag_api(self):
+        """Test flag URLs."""
+        # Not superuser
+        response = self.get(reverse('api-flag-list'), expected_code=200)
+        self.assertEqual(len(response.data), 2)
+        self.assertEqual(response.data[0]['key'], 'EXPERIMENTAL')
+
+        # Turn into superuser
+        self.user.is_superuser = True
+        self.user.save()
+
+        # Successful checks
+        response = self.get(reverse('api-flag-list'), expected_code=200)
+        self.assertEqual(len(response.data), 2)
+        self.assertEqual(response.data[0]['key'], 'EXPERIMENTAL')
+        self.assertTrue(response.data[0]['conditions'])
+
+        response = self.get(reverse('api-flag-detail', kwargs={'key': 'EXPERIMENTAL'}), expected_code=200)
+        self.assertEqual(len(response.data), 3)
+        self.assertEqual(response.data['key'], 'EXPERIMENTAL')
+        self.assertTrue(response.data['conditions'])
+
+        # Try without param -> false
+        response = self.get(reverse('api-flag-detail', kwargs={'key': 'NEXT_GEN'}), expected_code=200)
+        self.assertFalse(response.data['state'])
+
+        # Try with param -> true
+        response = self.get(reverse('api-flag-detail', kwargs={'key': 'NEXT_GEN'}), {'ngen': ''}, expected_code=200)
+        self.assertTrue(response.data['state'])
+
+        # Try non existent flag
+        response = self.get(reverse('api-flag-detail', kwargs={'key': 'NON_EXISTENT'}), expected_code=404)
+
+        # Turn into normal user again
+        self.user.is_superuser = False
+        self.user.save()
+
 
 class ColorThemeTest(TestCase):
     """Tests for ColorTheme."""

InvenTree/config_template.yaml

@@ -228,3 +228,11 @@ remote_login_header: HTTP_REMOTE_USER
 #   splash: splash_screen.jpg
 #   hide_admin_link: true
 #   hide_password_reset: true
+
+# Custom flags
+# InvenTree uses django-flags; read more in their docs at https://cfpb.github.io/django-flags/conditions/
+# Use environment variable INVENTREE_FLAGS or the settings below
+# flags:
+#  MY_FLAG:
+#     - condition: 'parameter'
+#       value: 'my_flag_param1'

InvenTree/users/models.py

@@ -81,6 +81,7 @@ class RuleSet(models.Model):
             'common_newsfeedentry',
             'taggit_tag',
             'taggit_taggeditem',
+            'flags_flagstate',
         ],
         'part_category': [
             'part_partcategory',

requirements.in

@@ -10,6 +10,7 @@ django-crispy-forms<2.0                 # Form helpers # FIXED 2023-02-18 due to
 django-dbbackup                         # Backup / restore of database and media files
 django-error-report                     # Error report viewer for the admin interface
 django-filter                           # Extended filtering options
+django-flags                            # Feature flags
 django-formtools                        # Form wizard tools
 django-ical                             # iCal export for calendar views
 django-import-export==2.5.0             # Data import / export for admin interface

requirements.txt

@@ -53,6 +53,7 @@ django==3.2.19
     #   django-dbbackup
     #   django-error-report
     #   django-filter
+    #   django-flags
     #   django-formtools
     #   django-ical
     #   django-import-export
@@ -92,6 +93,8 @@ django-error-report==0.2.0
     # via -r requirements.in
 django-filter==23.2
     # via -r requirements.in
+django-flags==5.0.12
+    # via -r requirements.in
 django-formtools==2.4.1
     # via -r requirements.in
 django-ical==1.9.1