Add nightly schedule for router validation

gso/schedules/__init__.py

 """Tasks that are scheduled to run periodically in :term:`GSO`."""
+
+from orchestrator.schedules import SchedulingFunction  # type:ignore[attr-defined]
+
+from gso.schedules.validate_routers_nightly import run_validate_routers
+
+#  TODO: This list overwrites the default, and therefore leaves all default schedules unused.
+#  TODO: Consider using the default schedules.
+ALL_SCHEDULERS: list[SchedulingFunction] = [run_validate_routers]

gso/schedules/validate_routers_nightly.py

+"""Nightly schedule for validating all active Routers' configuration."""
+
+import logging
+
+from orchestrator.schedules.scheduling import scheduler
+from orchestrator.services.processes import start_process
+
+from gso.services.subscriptions import get_active_router_subscriptions
+
+logger = logging.getLogger(__name__)
+
+
+@scheduler(name="Validate routers", time_unit="day", at="03:00")
+def run_validate_routers() -> None:
+    """Validate configuration on all active Routers, every night at 3AM."""
+    routers = get_active_router_subscriptions(includes=["subscription_id"])
+
+    for router in routers:
+        msg = f"Validating configuration of router subscription {router['subscription_id']}"
+        logger.info(msg)
+        start_process("validate_router", [{"subscription_id": router["subscription_id"]}])

gso/workflows/tasks/validate_router.py

+"""Router validation workflow. Used in a nightly schedule."""
+
 import json
 
 from orchestrator.targets import Target
-from orchestrator.types import State
 from orchestrator.utils.json import json_dumps
-from orchestrator.workflow import StepList, init, workflow, done, step
-from orchestrator.workflows.steps import store_process_subscription, unsync, resync
+from orchestrator.workflow import StepList, done, init, step, workflow
+from orchestrator.workflows.steps import resync, store_process_subscription, unsync
+from orchestrator.workflows.utils import wrap_modify_initial_input_form
+from products import Router
 
-from gso.services.provisioning_proxy import pp_interaction, execute_playbook
+from gso.services.provisioning_proxy import execute_playbook, pp_interaction
 from gso.workflows.router.create_router import verify_ipam_loopback
-from products import Router
 
 
 @step("Validate router configuration")
 def validate_router_config(subscription: Router, callback_route: str) -> None:
+    """Run an Ansible playbook that validates the configuration that is present on an active Router."""
     extra_vars = {"wfo_router_json": json.loads(json_dumps(subscription)), "verb": "validate"}
 
     execute_playbook(
         playbook_name="base_config.yaml",
         callback_route=callback_route,
         inventory=subscription.router.router_fqdn,
-        extra_vars=extra_vars
+        extra_vars=extra_vars,
     )
 
 
-@workflow("Validate router configuration", target=Target.SYSTEM)
+@workflow(
+    "Validate router configuration",
+    target=Target.SYSTEM,
+    initial_input_form=wrap_modify_initial_input_form(None),
+)
 def validate_router() -> StepList:
     """Validate an existing, active Router subscription.