Calculate disconnections in last hour (#11007)

Author: alexvru

ydb/library/actors/interconnect/interconnect_tcp_proxy.cpp

@@ -29,6 +29,7 @@ namespace NActors {
             Y_ABORT_UNLESS(!*DynamicPtr);
             *DynamicPtr = this;
         }
+        NumDisconnects.fill(0);
     }
 
     void TInterconnectProxyTCP::Bootstrap() {
@@ -942,4 +943,33 @@ namespace NActors {
         // TODO: unregister actor mon page
         TActor::PassAway();
     }
+
+    void TInterconnectProxyTCP::RegisterDisconnect() {
+        const TMonotonic now = TActivationContext::Monotonic();
+        ShiftDisconnectWindow(now);
+        ++NumDisconnectsInLastHour;
+        ++NumDisconnects[NumDisconnectsIndex];
+    }
+
+    ui32 TInterconnectProxyTCP::GetDisconnectCountInLastHour() {
+        ShiftDisconnectWindow(TMonotonic::Now());
+        return NumDisconnectsInLastHour;
+    }
+
+    void TInterconnectProxyTCP::ShiftDisconnectWindow(TMonotonic now) {
+        const ui64 currentMinutes = now.Minutes();
+        if (FirstDisconnectWindowMinutes) {
+            const ui32 steps = currentMinutes - FirstDisconnectWindowMinutes;
+            if (steps < NumDisconnectsSize) { // advance window by "steps" items, clearing them
+                for (ui32 i = 0; i < steps; ++i) {
+                    NumDisconnectsInLastHour -= std::exchange(NumDisconnects[++NumDisconnectsIndex %= NumDisconnectsSize], 0);
+                }
+            } else { // window has been fully flushed
+                NumDisconnects.fill(0);
+                NumDisconnectsInLastHour = 0;
+            }
+        }
+        FirstDisconnectWindowMinutes = currentMinutes;
+    }
+
 }

ydb/library/actors/interconnect/interconnect_tcp_proxy.h

@@ -565,6 +565,19 @@ namespace NActors {
         void HandleTerminate();
 
         void PassAway() override;
+
+        ////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+        // Disconnection management
+
+        static constexpr size_t NumDisconnectsSize = 60;
+        std::array<ui32, NumDisconnectsSize> NumDisconnects;
+        size_t NumDisconnectsIndex = 0;
+        ui32 NumDisconnectsInLastHour = 0;
+        ui64 FirstDisconnectWindowMinutes = 0;
+
+        void RegisterDisconnect();
+        ui32 GetDisconnectCountInLastHour();
+        void ShiftDisconnectWindow(TMonotonic now);
     };
 
 }

ydb/library/actors/interconnect/interconnect_tcp_session.cpp

@@ -542,6 +542,7 @@ namespace NActors {
             CloseOnIdleWatchdog.Disarm();
             LostConnectionWatchdog.Rearm(SelfId());
             Proxy->Metrics->SetConnected(0);
+            Proxy->RegisterDisconnect();
             LOG_INFO(*TlsActivationContext, NActorsServices::INTERCONNECT_STATUS, "[%u] disconnected", Proxy->PeerNodeId);
         }
         if (XdcSocket) {