feat(cloud): enforce host governance budgets

apps/device-host-agent/host_agent/heartbeat.py

@@ -8,6 +8,7 @@ from core.errors import DeviceRuntimeError
 from device.manager import DeviceManager
 from host_agent.client import HostAgentClient
 from host_agent.config import HostAgentConfig
+from host_agent.policy_cache import HostPolicyCacheStore
 from host_agent.status import AgentStatusTracker
 
 if TYPE_CHECKING:
@@ -37,6 +38,8 @@ class HeartbeatSynchronizer:
         sleep: Callable[[float], Awaitable[None]] = asyncio.sleep,
         status_tracker: AgentStatusTracker | None = None,
         on_sync: Callable[[int], None] | None = None,
+        policy_cache: HostPolicyCacheStore | None = None,
+        on_policy_sync: Callable[[int], None] | None = None,
     ) -> None:
         self.manager = manager
         self.client = client
@@ -45,8 +48,12 @@ class HeartbeatSynchronizer:
         self._sleep = sleep
         self.status_tracker = status_tracker
         self.on_sync = on_sync
-        self.policy_revision = 0
-        self.policy = None
+        self.policy_cache = policy_cache
+        self.on_policy_sync = on_policy_sync
+        self.policy = policy_cache.load() if policy_cache is not None else None
+        self.policy_revision = self.policy.revision if self.policy is not None else 0
+        if self.status_tracker is not None:
+            self.status_tracker.mark_host_policy(self.policy)
 
     async def sync_once(self) -> HeartbeatResponse:
         snapshot = build_device_snapshot(self.manager)
@@ -58,6 +65,16 @@ class HeartbeatSynchronizer:
         self.policy_revision = response.policy_revision
         if response.policy is not None:
             self.policy = response.policy
+            if self.policy_cache is not None:
+                self.policy_cache.save(response.policy)
+            if self.on_policy_sync is not None:
+                self.on_policy_sync(response.policy.revision)
+        elif response.policy_revision == 0:
+            self.policy = None
+            if self.policy_cache is not None:
+                self.policy_cache.clear()
+        if self.status_tracker is not None:
+            self.status_tracker.mark_host_policy(self.policy)
         if self.status_tracker is not None:
             self.status_tracker.mark_heartbeat(ok=True, device_count=len(snapshot))
         if self.on_sync is not None: