feat(notifications): add EDA-based idempotent processing and DLQ for chapter/event updates

backend/Makefile

@@ -156,6 +156,9 @@ run-backend-fuzz:
 	@COMPOSE_BAKE=true DOCKER_BUILDKIT=1 \
 	docker compose --project-name nest-fuzz -f docker-compose/fuzz/compose.yaml up --build --remove-orphans --abort-on-container-exit backend db cache
 
+run-notification-worker:
+	@CMD="python manage.py owasp_run_notification_worker" $(MAKE) exec-backend-command-it
+
 save-backup:
 	@echo "Saving Nest backup"
 	@CMD="python manage.py dumpdata --natural-primary --natural-foreign --indent=2" $(MAKE) exec-backend-command > backend/data/backup.json

backend/apps/owasp/Makefile

@@ -11,6 +11,10 @@ owasp-aggregate-member-contributions:
 	@echo "Aggregating OWASP community member contributions"
 	@CMD="python manage.py owasp_aggregate_member_contributions" $(MAKE) exec-backend-command
 
+owasp-check-event-deadlines:
+	@echo "Checking OWASP event deadlines"
+	@CMD="python manage.py owasp_check_event_deadlines" $(MAKE) exec-backend-command
+
 owasp-create-project-metadata-file:
 	@echo "Generating metadata"
 	@CMD="python manage.py owasp_create_project_metadata_file $(entity_key)" $(MAKE) exec-backend-command

backend/apps/owasp/admin/notification.py

@@ -0,0 +1,24 @@
+"""Admin registration for notification models."""
+
+from django.contrib import admin
+
+from apps.owasp.models.notification import Notification, Subscription
+
+
+@admin.register(Subscription)
+class SubscriptionAdmin(admin.ModelAdmin):
+    """Admin for Subscription model."""
+
+    list_display = ("user", "content_type", "object_id", "created_at")
+    list_filter = ("content_type", "created_at")
+    search_fields = ("user__email", "user__username")
+
+
+@admin.register(Notification)
+class NotificationAdmin(admin.ModelAdmin):
+    """Admin for Notification model."""
+
+    list_display = ("recipient", "type", "title", "is_read", "created_at")
+    list_filter = ("type", "is_read", "created_at")
+    search_fields = ("recipient__email", "recipient__username", "title", "message")
+    readonly_fields = ("created_at",)

backend/apps/owasp/apps.py

@@ -7,3 +7,9 @@ class OwaspConfig(AppConfig):
     """Owasp app config."""
 
     name = "apps.owasp"
+
+    def ready(self):
+        """Import signals when app is ready."""
+        import apps.owasp.signals.chapter
+        import apps.owasp.signals.event
+        import apps.owasp.signals.snapshot  # noqa: F401

backend/apps/owasp/management/commands/owasp_check_event_deadlines.py

@@ -0,0 +1,36 @@
+"""Management command to check for approaching event deadlines."""
+
+import logging
+
+from django.core.management.base import BaseCommand
+from django.utils import timezone
+
+from apps.owasp.models.event import Event
+from apps.owasp.utils.notifications import publish_event_notification
+
+logger = logging.getLogger(__name__)
+
+REMINDER_DAYS = (7, 3, 1)
+
+
+class Command(BaseCommand):
+    """Check for events with approaching deadlines and queue reminder notifications."""
+
+    help = "Check for events with approaching deadlines and send reminder notifications."
+
+    def handle(self, *args, **options):
+        """Handle execution."""
+        self.stdout.write("Checking for approaching event deadlines...")
+        today = timezone.now().date()
+        total_reminders = 0
+
+        for days in REMINDER_DAYS:
+            target_date = today + timezone.timedelta(days=days)
+            events = Event.objects.filter(start_date=target_date)
+
+            for event in events:
+                self.stdout.write(f"  Event '{event.name}' starts in {days} days ({target_date})")
+                publish_event_notification(event, "deadline_reminder", days_remaining=days)
+                total_reminders += 1
+
+        self.stdout.write(self.style.SUCCESS(f"Queued {total_reminders} deadline reminder(s)."))

backend/apps/owasp/management/commands/owasp_notification_dlq.py

@@ -0,0 +1,169 @@
+"""Management command to manage notification DLQ."""
+
+import sys
+
+from django.core.mail import send_mail
+from django.core.management.base import BaseCommand
+from django_redis import get_redis_connection
+
+
+class Command(BaseCommand):
+    """Manage notification DLQ manually."""
+
+    help = "Manage notification DLQ: list, retry, or remove failed notifications"
+
+    DLQ_STREAM_KEY = "owasp_notifications_dlq"
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "action",
+            type=str,
+            choices=["list", "retry", "remove"],
+            help="Action to perform: list, retry, or remove",
+        )
+        parser.add_argument(
+            "--id",
+            type=str,
+            help="Specific message ID to act on (required for retry/remove unless --all is used)",
+        )
+        parser.add_argument(
+            "--all",
+            action="store_true",
+            help="Apply action to all messages",
+        )
+
+    def handle(self, *args, **options):
+        action = options["action"]
+        message_id = options.get("id")
+        all_messages = options.get("all")
+
+        redis_conn = get_redis_connection("default")
+
+        if action == "list":
+            self.list_dlq(redis_conn)
+        elif action == "retry":
+            if not message_id and not all_messages:
+                self.stdout.write(self.style.ERROR("Error: --id or --all is required for retry"))
+                sys.exit(1)
+            self.retry_dlq(redis_conn, message_id, all_messages)
+        elif action == "remove":
+            if not message_id and not all_messages:
+                self.stdout.write(self.style.ERROR("Error: --id or --all is required for remove"))
+                sys.exit(1)
+            self.remove_dlq(redis_conn, message_id, all_messages)
+
+    def list_dlq(self, redis_conn):
+        """List all failed notifications in DLQ."""
+        messages = redis_conn.xrange(self.DLQ_STREAM_KEY, "-", "+")
+
+        if not messages:
+            self.stdout.write(self.style.SUCCESS("DLQ is empty - no failed notifications"))
+            return
+
+        self.stdout.write("\n" + "=" * 100)
+        self.stdout.write(
+            f"{'ID':<20} | {'Email':<25} | {'Type':<18} | {'Entity':<15} | {'Retries':<8}"
+        )
+        self.stdout.write("=" * 100)
+
+        for msg_id, data in messages:
+            msg_id_str = msg_id.decode("utf-8") if isinstance(msg_id, bytes) else msg_id
+            user_email = self._get_value(data, b"user_email", "unknown")
+            notif_type = self._get_value(data, b"notification_type", "unknown")
+            entity_name = self._get_value(data, b"entity_name", "unknown")[:15]
+            retries = self._get_value(data, b"dlq_retries", "0")
+
+            self.stdout.write(
+                f"{msg_id_str:<20} | {user_email:<25} | "
+                f"{notif_type:<18} | {entity_name:<15} | {retries:<8}"
+            )
+
+        self.stdout.write("=" * 100)
+        self.stdout.write(f"Total: {len(messages)} failed notification(s)\n")
+
+    def retry_dlq(self, redis_conn, message_id, all_messages):
+        """Retry failed notification(s)."""
+        if all_messages:
+            messages = redis_conn.xrange(self.DLQ_STREAM_KEY, "-", "+")
+        else:
+            result = redis_conn.xrange(self.DLQ_STREAM_KEY, message_id, message_id)
+            messages = result or []
+
+        if not messages:
+            self.stdout.write(self.style.ERROR("Message(s) not found"))
+            return
+
+        success_count = 0
+        error_count = 0
+
+        for msg_id, data in messages:
+            if not data:
+                continue
+
+            try:
+                user_email = self._get_value(data, b"user_email")
+                title = self._get_value(data, b"title")
+                message = self._get_value(data, b"message")
+                related_link = self._get_value(data, b"related_link")
+
+                if user_email and title and message:
+                    full_message = (
+                        f"{message}\n\nView: {related_link}" if related_link else message
+                    )
+                    send_mail(
+                        subject=title,
+                        message=full_message,
+                        from_email="noreply@owasp.org",
+                        recipient_list=[user_email],
+                        fail_silently=False,
+                    )
+                    redis_conn.xdel(self.DLQ_STREAM_KEY, msg_id)
+                    success_count += 1
+                    self.stdout.write(f"Retried: {msg_id} -> {user_email}")
+                else:
+                    self.stdout.write(self.style.WARNING(f"Skipped (missing data): {msg_id}"))
+                    error_count += 1
+
+            except Exception as e:  # noqa: BLE001
+                error_count += 1
+                retries = int(self._get_value(data, b"dlq_retries", "0"))
+                new_retries = str(retries + 1)
+                data[b"dlq_retries"] = new_retries.encode()
+                new_msg = {k.decode(): v.decode() for k, v in data.items()}
+                redis_conn.xdel(self.DLQ_STREAM_KEY, msg_id)
+                redis_conn.xadd(self.DLQ_STREAM_KEY, new_msg)
+                self.stdout.write(
+                    self.style.ERROR(f"Failed to retry {msg_id}: {e}, incremented retries")
+                )
+
+        self.stdout.write(
+            self.style.SUCCESS(
+                f"\nRetry complete: {success_count} succeeded, {error_count} failed/retried"
+            )
+        )
+
+    def remove_dlq(self, redis_conn, message_id, all_messages):
+        """Remove failed notification(s) from DLQ."""
+        if all_messages:
+            messages = redis_conn.xrange(self.DLQ_STREAM_KEY, "-", "+")
+        else:
+            messages = redis_conn.xrange(self.DLQ_STREAM_KEY, message_id, message_id)
+
+        if not messages:
+            self.stdout.write(self.style.ERROR("No messages found"))
+            return
+
+        count = 0
+        for msg_id, _ in messages:
+            redis_conn.xdel(self.DLQ_STREAM_KEY, msg_id)
+            count += 1
+            self.stdout.write(f"Removed: {msg_id}")
+
+        self.stdout.write(self.style.SUCCESS(f"\nRemoved {count} message(s) from DLQ"))
+
+    def _get_value(self, data, key, default=None):
+        """Get value from message data."""
+        value = data.get(key.encode() if isinstance(key, str) else key)
+        if value:
+            return value.decode("utf-8")
+        return default