Promote VPN pressure action to snapshot

agents/rap-node-agent/internal/vpnruntime/fabric_transport.go

@@ -255,6 +255,7 @@ type FabricFlowSchedulerSnapshot struct {
 	PressureLevel              string                    `json:"pressure_level,omitempty"`
 	PressureScore              int                       `json:"pressure_score,omitempty"`
 	PressureReasons            []string                  `json:"pressure_reasons,omitempty"`
+	RecommendedAction          string                    `json:"recommended_action,omitempty"`
 	InFlight                   int                       `json:"in_flight"`
 	MaxInFlight                int                       `json:"max_in_flight"`
 	AdaptiveBackpressureActive bool                      `json:"adaptive_backpressure_active,omitempty"`
@@ -864,6 +865,7 @@ func (s *FabricFlowScheduler) Snapshot() FabricFlowSchedulerSnapshot {
 		}
 	}
 	snapshot.PressureLevel, snapshot.PressureScore, snapshot.PressureReasons = fabricFlowSchedulerPressure(snapshot)
+	snapshot.RecommendedAction = fabricFlowSchedulerRecommendedAction(snapshot)
 	return snapshot
 }
 
@@ -940,6 +942,32 @@ func flowPressureRank(level string) int {
 	}
 }
 
+func fabricFlowSchedulerRecommendedAction(snapshot FabricFlowSchedulerSnapshot) string {
+	reasons := map[string]struct{}{}
+	for _, reason := range snapshot.PressureReasons {
+		reasons[strings.TrimSpace(reason)] = struct{}{}
+	}
+	if _, ok := reasons["drops"]; ok || snapshot.QualityWindowDropCount > 0 {
+		return "shed_or_reroute"
+	}
+	if _, ok := reasons["route_failures"]; ok || snapshot.QualityWindowFailureCount > 0 || snapshot.FailingChannelCount > 0 {
+		return "rebuild_or_reroute"
+	}
+	if _, ok := reasons["route_recovery"]; ok || snapshot.RouteSwitchCount > 0 {
+		return "observe_recovery"
+	}
+	if _, ok := reasons["slow_channels"]; ok || snapshot.SlowChannelCount > 0 || snapshot.QualityWindowSlowCount > 0 {
+		return "prefer_faster_route"
+	}
+	if _, ok := reasons["bulk_pressure"]; ok || snapshot.BulkPressureActive {
+		return "throttle_bulk"
+	}
+	if snapshot.AdaptiveBackpressureActive || snapshot.BackpressureActive {
+		return "reduce_parallelism"
+	}
+	return "observe"
+}
+
 func boundedFabricPressureScore(value, minValue, maxValue int) int {
 	if value < minValue {
 		return minValue

agents/rap-node-agent/internal/vpnruntime/fabric_transport_test.go

@@ -792,6 +792,9 @@ func TestFabricFlowSchedulerDropsWhenChannelQueueIsFull(t *testing.T) {
 	if snapshot.PressureLevel != "critical" || snapshot.PressureScore <= 0 || !containsString(snapshot.PressureReasons, "drops") {
 		t.Fatalf("pressure = %s score=%d reasons=%v, want critical drops", snapshot.PressureLevel, snapshot.PressureScore, snapshot.PressureReasons)
 	}
+	if snapshot.RecommendedAction != "shed_or_reroute" {
+		t.Fatalf("recommended action = %q, want shed_or_reroute", snapshot.RecommendedAction)
+	}
 }
 
 func TestFabricFlowSchedulerRoundsSubMillisecondSendDuration(t *testing.T) {
@@ -1553,6 +1556,9 @@ func TestFabricClientPacketIngressIsolatesRouteFailoverPerLogicalChannel(t *test
 		!containsString(snapshot.FlowScheduler.PressureReasons, "route_failures") {
 		t.Fatalf("route recovery pressure = %s score=%d reasons=%v", snapshot.FlowScheduler.PressureLevel, snapshot.FlowScheduler.PressureScore, snapshot.FlowScheduler.PressureReasons)
 	}
+	if snapshot.FlowScheduler.RecommendedAction != "rebuild_or_reroute" {
+		t.Fatalf("route recovery action = %q, want rebuild_or_reroute", snapshot.FlowScheduler.RecommendedAction)
+	}
 	if statB.LastRouteID != "route-primary" || statB.LastFailedRouteID != "" || statB.ConsecutiveFailures != 0 {
 		t.Fatalf("channel B stat = %+v, want primary route memory preserved", statB)
 	}
@@ -1923,6 +1929,9 @@ func TestFabricFlowSchedulerProtectsInteractiveWindowDuringBulkPressure(t *testi
 	if snapshot.PressureLevel != "warning" || snapshot.PressureScore <= 0 || !containsString(snapshot.PressureReasons, "bulk_pressure") {
 		t.Fatalf("pressure = %s score=%d reasons=%v, want warning bulk pressure", snapshot.PressureLevel, snapshot.PressureScore, snapshot.PressureReasons)
 	}
+	if snapshot.RecommendedAction != "throttle_bulk" {
+		t.Fatalf("recommended action = %q, want throttle_bulk", snapshot.RecommendedAction)
+	}
 }
 
 func TestFabricFlowSchedulerRollingQualityWindowForgetsOldPressure(t *testing.T) {