add cron-based schedule trigger

surfsense_backend/app/automations/triggers/schedule/dispatch.py

@@ -0,0 +1,48 @@
+"""Schedule dispatch adapter: load + guard, then call generic dispatch."""
+
+from __future__ import annotations
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.automations.dispatch import DispatchError, dispatch_run
+from app.automations.persistence.enums.automation_status import AutomationStatus
+from app.automations.persistence.models.automation import Automation
+from app.automations.persistence.models.run import AutomationRun
+from app.automations.persistence.models.trigger import AutomationTrigger
+
+
+async def dispatch_schedule_run(
+    *,
+    session: AsyncSession,
+    trigger: AutomationTrigger,
+) -> AutomationRun:
+    """Fire one scheduled run for ``trigger``.
+
+    The caller (the schedule tick) is responsible for selecting due triggers
+    and advancing ``next_fire_at`` / ``last_fired_at`` before invoking this.
+    """
+    automation = await _load_automation(session, trigger.automation_id)
+    if automation is None:
+        raise DispatchError(
+            f"automation {trigger.automation_id} not found for trigger {trigger.id}"
+        )
+
+    if automation.status != AutomationStatus.ACTIVE:
+        raise DispatchError(
+            f"automation {trigger.automation_id} is {automation.status.value}, not active"
+        )
+
+    return await dispatch_run(
+        session=session,
+        automation=automation,
+        trigger=trigger,
+        payload=None,
+    )
+
+
+async def _load_automation(
+    session: AsyncSession, automation_id: int
+) -> Automation | None:
+    stmt = select(Automation).where(Automation.id == automation_id)
+    return (await session.execute(stmt)).scalar_one_or_none()