feat: add feature toggle system for disabling modules and UI

examples/settings.py

@@ -56,6 +56,7 @@
                 "django.template.context_processors.request",
                 "django.contrib.auth.context_processors.auth",
                 "django.contrib.messages.context_processors.messages",
+                "django_program.context_processors.program_features",
             ],
         },
     },

src/django_program/conference/admin.py

@@ -3,7 +3,7 @@
 from django import forms
 from django.contrib import admin
 
-from django_program.conference.models import Conference, Section
+from django_program.conference.models import Conference, FeatureFlags, Section
 
 SECRET_PLACEHOLDER = "\u2022" * 12
 
@@ -86,21 +86,83 @@ class SectionInline(admin.TabularInline):
     fields = ("name", "slug", "start_date", "end_date", "order")
 
 
+class FeatureFlagsForm(forms.ModelForm):
+    """Form for FeatureFlags that replaces 'Unknown' with 'Default (enabled)'.
+
+    Each nullable boolean field defaults to ``None`` which means "use the
+    value from ``DJANGO_PROGRAM['features']`` in settings".  Since the
+    out-of-the-box default for every feature is ``True``, the widget
+    label reads "Default (enabled)" instead of Django's generic "Unknown".
+    """
+
+    class Meta:
+        model = FeatureFlags
+        exclude: list[str] = []
+
+    def __init__(self, *args: object, **kwargs: object) -> None:
+        """Replace 'Unknown' widget labels with 'Default (enabled)'."""
+        super().__init__(*args, **kwargs)
+        for field in self.fields.values():
+            if isinstance(field.widget, forms.NullBooleanSelect):
+                field.widget.choices = [
+                    ("unknown", "Default (enabled)"),
+                    ("true", "Yes — force ON"),
+                    ("false", "No — force OFF"),
+                ]
+
+
+class FeatureFlagsInline(admin.StackedInline):
+    """Inline editor for per-conference feature flag overrides.
+
+    Allows toggling individual features directly from the conference
+    admin change form. At most one ``FeatureFlags`` row per conference.
+    """
+
+    model = FeatureFlags
+    form = FeatureFlagsForm
+    extra = 0
+    max_num = 1
+    fieldsets = (
+        (
+            "Module Toggles",
+            {
+                "fields": (
+                    "registration_enabled",
+                    "sponsors_enabled",
+                    "travel_grants_enabled",
+                    "programs_enabled",
+                    "pretalx_sync_enabled",
+                ),
+            },
+        ),
+        (
+            "UI Toggles",
+            {
+                "fields": (
+                    "public_ui_enabled",
+                    "manage_ui_enabled",
+                    "all_ui_enabled",
+                ),
+            },
+        ),
+    )
+
+
 @admin.register(Conference)
 class ConferenceAdmin(admin.ModelAdmin):
     """Admin interface for managing conferences.
 
     Groups fields into logical fieldsets: basic information, dates,
     third-party integrations (Pretalx and Stripe), and status metadata.
-    Sections are editable inline via ``SectionInline``.
+    Sections and feature flags are editable inline.
     """
 
     form = ConferenceForm
     list_display = ("name", "slug", "start_date", "end_date", "is_active")
     list_filter = ("is_active",)
     search_fields = ("name", "slug")
     prepopulated_fields = {"slug": ("name",)}
-    inlines = (SectionInline,)
+    inlines = (SectionInline, FeatureFlagsInline)
 
     fieldsets = (
         (
@@ -148,3 +210,49 @@ class SectionAdmin(admin.ModelAdmin):
     list_filter = ("conference",)
     search_fields = ("name", "slug")
     prepopulated_fields = {"slug": ("name",)}
+
+
+@admin.register(FeatureFlags)
+class FeatureFlagsAdmin(admin.ModelAdmin):
+    """Standalone admin for per-conference feature flag overrides.
+
+    Provides a list view for quick scanning across conferences.
+    The same data is also editable inline on the Conference admin page.
+    """
+
+    form = FeatureFlagsForm
+    list_display = (
+        "conference",
+        "registration_enabled",
+        "sponsors_enabled",
+        "travel_grants_enabled",
+        "programs_enabled",
+        "public_ui_enabled",
+        "updated_at",
+    )
+    list_filter = ("conference",)
+    fieldsets = (
+        ("Conference", {"fields": ("conference",)}),
+        (
+            "Module Toggles",
+            {
+                "fields": (
+                    "registration_enabled",
+                    "sponsors_enabled",
+                    "travel_grants_enabled",
+                    "programs_enabled",
+                    "pretalx_sync_enabled",
+                ),
+            },
+        ),
+        (
+            "UI Toggles",
+            {
+                "fields": (
+                    "public_ui_enabled",
+                    "manage_ui_enabled",
+                    "all_ui_enabled",
+                ),
+            },
+        ),
+    )

src/django_program/conference/apps.py

@@ -10,3 +10,7 @@ class DjangoProgramConferenceConfig(AppConfig):
     name = "django_program.conference"
     label = "program_conference"
     verbose_name = "Conference"
+
+    def ready(self) -> None:
+        """Import signal handlers."""
+        import django_program.conference.signals  # noqa: F401, PLC0415

src/django_program/conference/migrations/0004_add_feature_flags.py

@@ -0,0 +1,62 @@
+# Generated by Django 5.2.11 on 2026-02-14 01:39
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("program_conference", "0003_conference_address"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="FeatureFlags",
+            fields=[
+                ("id", models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name="ID")),
+                (
+                    "registration_enabled",
+                    models.BooleanField(
+                        blank=True,
+                        help_text="Override registration toggle. Leave blank to use default from settings.",
+                        null=True,
+                    ),
+                ),
+                ("sponsors_enabled", models.BooleanField(blank=True, help_text="Override sponsors toggle.", null=True)),
+                (
+                    "travel_grants_enabled",
+                    models.BooleanField(blank=True, help_text="Override travel grants toggle.", null=True),
+                ),
+                (
+                    "programs_enabled",
+                    models.BooleanField(blank=True, help_text="Override programs/activities toggle.", null=True),
+                ),
+                (
+                    "pretalx_sync_enabled",
+                    models.BooleanField(blank=True, help_text="Override Pretalx sync toggle.", null=True),
+                ),
+                (
+                    "public_ui_enabled",
+                    models.BooleanField(blank=True, help_text="Override public UI toggle.", null=True),
+                ),
+                (
+                    "manage_ui_enabled",
+                    models.BooleanField(blank=True, help_text="Override manage UI toggle.", null=True),
+                ),
+                ("all_ui_enabled", models.BooleanField(blank=True, help_text="Master UI switch override.", null=True)),
+                ("updated_at", models.DateTimeField(auto_now=True)),
+                (
+                    "conference",
+                    models.OneToOneField(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="feature_flags",
+                        to="program_conference.conference",
+                    ),
+                ),
+            ],
+            options={
+                "verbose_name": "feature flags",
+                "verbose_name_plural": "feature flags",
+            },
+        ),
+    ]

src/django_program/conference/models.py

@@ -62,3 +62,69 @@ class Meta:
 
     def __str__(self) -> str:
         return f"{self.name} ({self.conference.slug})"
+
+
+class FeatureFlags(models.Model):
+    """Per-conference feature toggle overrides.
+
+    Database-backed flags that override the defaults from
+    ``DJANGO_PROGRAM["features"]``. Changes take effect immediately
+    without server restart. Each conference has at most one row.
+
+    All boolean fields are nullable: ``None`` means "use default from
+    settings", while an explicit ``True`` or ``False`` overrides.
+    """
+
+    conference = models.OneToOneField(
+        "program_conference.Conference",
+        on_delete=models.CASCADE,
+        related_name="feature_flags",
+    )
+    registration_enabled = models.BooleanField(
+        null=True,
+        blank=True,
+        help_text="Override registration toggle. Leave blank to use default from settings.",
+    )
+    sponsors_enabled = models.BooleanField(
+        null=True,
+        blank=True,
+        help_text="Override sponsors toggle.",
+    )
+    travel_grants_enabled = models.BooleanField(
+        null=True,
+        blank=True,
+        help_text="Override travel grants toggle.",
+    )
+    programs_enabled = models.BooleanField(
+        null=True,
+        blank=True,
+        help_text="Override programs/activities toggle.",
+    )
+    pretalx_sync_enabled = models.BooleanField(
+        null=True,
+        blank=True,
+        help_text="Override Pretalx sync toggle.",
+    )
+    public_ui_enabled = models.BooleanField(
+        null=True,
+        blank=True,
+        help_text="Override public UI toggle.",
+    )
+    manage_ui_enabled = models.BooleanField(
+        null=True,
+        blank=True,
+        help_text="Override manage UI toggle.",
+    )
+    all_ui_enabled = models.BooleanField(
+        null=True,
+        blank=True,
+        help_text="Master UI switch override.",
+    )
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        verbose_name = "feature flags"
+        verbose_name_plural = "feature flags"
+
+    def __str__(self) -> str:
+        return f"Feature flags for {self.conference}"

src/django_program/conference/signals.py

@@ -0,0 +1,19 @@
+"""Signals for the conference app."""
+
+from django.db.models.signals import post_save
+from django.dispatch import receiver
+
+from django_program.conference.models import Conference, FeatureFlags
+
+
+@receiver(post_save, sender=Conference)
+def create_feature_flags(
+    sender: type[Conference],  # noqa: ARG001
+    instance: Conference,
+    *,
+    created: bool,
+    **kwargs: object,  # noqa: ARG001
+) -> None:
+    """Auto-create a FeatureFlags row when a new Conference is saved."""
+    if created:
+        FeatureFlags.objects.get_or_create(conference=instance)

src/django_program/context_processors.py

@@ -0,0 +1,39 @@
+"""Django context processors for django-program."""
+
+from django.http import HttpRequest  # noqa: TC002 -- used in runtime annotation (PEP 649)
+
+from django_program.features import is_feature_enabled
+
+# Feature names that correspond to FeaturesConfig boolean attributes.
+_FEATURE_NAMES = (
+    "registration",
+    "sponsors",
+    "travel_grants",
+    "programs",
+    "pretalx_sync",
+    "public_ui",
+    "manage_ui",
+    "all_ui",
+)
+
+
+def program_features(request: HttpRequest) -> dict[str, dict[str, bool]]:
+    """Expose resolved feature toggle flags to templates.
+
+    Each flag is resolved through :func:`~django_program.features.is_feature_enabled`
+    so that master-switch overrides (e.g. ``all_ui_enabled``) are applied.
+    When the request carries a ``conference`` attribute (set by middleware
+    or the view), per-conference DB overrides are included in the resolution.
+
+    Add ``"django_program.context_processors.program_features"`` to the
+    ``context_processors`` list in your ``TEMPLATES`` setting.
+
+    Usage in templates::
+
+        {% if program_features.registration_enabled %}
+            <a href="{% url 'registration:ticket-list' %}">Registration</a>
+        {% endif %}
+    """
+    conference = getattr(request, "conference", None)
+    resolved = {f"{name}_enabled": is_feature_enabled(name, conference=conference) for name in _FEATURE_NAMES}
+    return {"program_features": resolved}