Initial Commit - Lesson 31 (Commit #1)

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/GameLiftMetrics.cpp

@@ -0,0 +1,319 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include "GameLiftMetrics.h"
+#include "GameLiftMetricsTypes.h"
+#include "GameLiftMetricsConfig.h"
+#include "UnrealStatCollector.h"
+#include "TickableCollector.h"
+
+#include "GameLiftServerSDK.h"
+#include "aws/gamelift/server/GameLiftServerAPI.h"
+
+#include "Sockets.h"
+#include "SocketSubsystem.h"
+#include "IPAddress.h"
+#include "Common/UdpSocketBuilder.h"
+
+#include <aws/gamelift/metrics/GlobalMetricsProcessor.h>
+
+#if PLATFORM_LINUX
+#include <unistd.h>
+#endif
+
+FString FGameLiftMetricsModule::CurrentGameSessionId;
+FThreadSafeCounter FGameLiftMetricsModule::CurrentPlayerCount(0);
+
+FGameLiftMetricsModule& FGameLiftMetricsModule::Load()
+{
+    return FModuleManager::LoadModuleChecked<FGameLiftMetricsModule>(FName("GameLiftMetrics"));
+}
+
+FGameLiftMetricsModule& FGameLiftMetricsModule::Get()
+{
+    return FModuleManager::GetModuleChecked<FGameLiftMetricsModule>(FName("GameLiftMetrics"));
+}
+
+FGameLiftMetricsModule* FGameLiftMetricsModule::GetPtr()
+{
+    return FModuleManager::GetModulePtr<FGameLiftMetricsModule>(FName("GameLiftMetrics"));
+}
+
+#if WITH_GAMELIFT_METRICS
+namespace
+{
+    const TCHAR* GAMELIFT_METRICS_FLEET_ID = TEXT("GAMELIFT_SDK_FLEET_ID");
+    const TCHAR* GAMELIFT_METRICS_PROCESS_ID = TEXT("GAMELIFT_SDK_PROCESS_ID");
+
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricMaxPlayers, "server_max_players", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricMaxPlayers);
+
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricPlayers, "server_players", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricPlayers);
+
+    GAMELIFT_METRICS_DECLARE_COUNTER(MetricServerCrashes, "game_server_crashes", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DEFINE_COUNTER(MetricServerCrashes);
+}
+
+void FGameLiftMetricsModule::StartupModule() {}
+
+void FGameLiftMetricsModule::ShutdownModule()
+{
+    // Terminate here just in case the user forgot.
+    Terminate();
+}
+
+void FGameLiftMetricsModule::StartMetricsCollector()
+{
+    FPlatformMisc::SetCrashHandler(&FGameLiftMetricsModule::CrashHandler);
+
+    bMetricsRunning = true;
+
+    auto *Module = FGameLiftMetricsModule::GetPtr();
+    if (!Module)
+    {
+        UE_LOG(LogGameLiftMetrics, Error, TEXT("GameLiftMetrics module no longer loaded."));
+        return;
+    }
+
+    /*
+     * Begin ticking the collector.
+     */
+    const bool bComputeFallbackGameThreadTime = !STATS;
+    Module->Collector.Reset(new FTickableCollector(bComputeFallbackGameThreadTime));
+
+    /*
+     * Create stats collector.
+     */
+    if (STATS)
+    {
+        Module->UnrealStatCollector = TSharedPtr<FUnrealStatCollector>(new FUnrealStatCollector());
+        Module->UnrealStatCollector->Subscribe();
+    }
+
+    UE_LOG(LogGameLiftMetrics, Log, TEXT("GameLift metrics initialized successfully."));
+}
+
+void FGameLiftMetricsModule::Initialize()
+{
+    if (GIsEditor) return;
+
+    // Initialize GameLift Server SDK metrics
+    auto& ServerSDKModule = FModuleManager::LoadModuleChecked<FGameLiftServerSDKModule>("GameLiftServerSDK");
+    auto InitResult = ServerSDKModule.InitMetrics();
+    if (!InitResult.IsSuccess())
+    {
+        UE_LOG(LogGameLiftMetrics, Error, TEXT("Failed to initialize GameLift metrics: %s"), *InitResult.GetError().m_errorMessage);
+        return;
+    }
+
+    StartMetricsCollector();
+}
+
+void FGameLiftMetricsModule::Initialize(const FMetricsParameters& metricsParameters)
+{
+    if (GIsEditor) return;
+
+    // Initialize GameLift Server SDK metrics with parameters
+    auto& ServerSDKModule = FModuleManager::LoadModuleChecked<FGameLiftServerSDKModule>("GameLiftServerSDK");
+    auto InitResult = ServerSDKModule.InitMetrics(metricsParameters);
+    if (!InitResult.IsSuccess())
+    {
+        UE_LOG(LogGameLiftMetrics, Error, TEXT("Failed to initialize GameLift metrics with parameters: %s"), *InitResult.GetError().m_errorMessage);
+        return;
+    }
+
+    StartMetricsCollector();
+}
+
+void FGameLiftMetricsModule::Terminate()
+{
+    if (GIsEditor) { return; }
+
+    if (UnrealStatCollector)
+    {
+        UnrealStatCollector->Unsubscribe();
+        UnrealStatCollector.Reset();
+    }
+
+    Collector.Reset();
+
+    UE_LOG(LogGameLiftMetrics, Log, TEXT("GameLift metrics terminated successfully."));
+}
+
+void FGameLiftMetricsModule::OnStartGameSession(const Aws::GameLift::Server::Model::GameSession& Session)
+{
+    if (GIsEditor) { return; }
+
+    // Store the session ID regardless of metrics being enabled
+    CurrentGameSessionId = FString(Session.GetGameSessionId());
+    CurrentPlayerCount.Set(0);
+
+    const UGameLiftMetricsConfig& Config = UGameLiftMetricsConfig::Get();
+    if (!Config.bEnableMetrics)
+    {
+        UE_LOG(LogGameLiftMetrics, Verbose, TEXT("Metrics disabled: Skipping OnStartGameSession metrics"));
+        return;
+    }
+
+    GAMELIFT_METRICS_SET(MetricMaxPlayers, Session.GetMaximumPlayerSessionCount());
+    GAMELIFT_METRICS_RESET(MetricPlayers);
+}
+
+void FGameLiftMetricsModule::OnAcceptPlayerSession()
+{
+    if (GIsEditor) { return; }
+
+    // Always track player count even if metrics are disabled
+    int32 NewPlayerCount = CurrentPlayerCount.Increment();
+
+    const UGameLiftMetricsConfig& Config = UGameLiftMetricsConfig::Get();
+    if (!Config.bEnableMetrics)
+    {
+        return;
+    }
+
+    GAMELIFT_METRICS_SET(MetricPlayers, NewPlayerCount);
+}
+
+void FGameLiftMetricsModule::OnRemovePlayerSession()
+{
+    if (GIsEditor) { return; }
+
+    // Always track player count even if metrics are disabled
+    int32 NewPlayerCount = CurrentPlayerCount.Decrement();
+    if (NewPlayerCount < 0)
+    {
+        CurrentPlayerCount.Set(0);
+        NewPlayerCount = 0;
+    }
+
+    const UGameLiftMetricsConfig& Config = UGameLiftMetricsConfig::Get();
+    if (!Config.bEnableMetrics)
+    {
+        return;
+    }
+
+    GAMELIFT_METRICS_SET(MetricPlayers, NewPlayerCount);
+}
+
+void FGameLiftMetricsModule::ReEmitMetrics()
+{
+    if (GIsEditor) { return; }
+
+    const UGameLiftMetricsConfig& Config = UGameLiftMetricsConfig::Get();
+    if (!Config.bEnableMetrics)
+    {
+        return;
+    }
+
+    GAMELIFT_METRICS_SET(MetricPlayers, CurrentPlayerCount.GetValue());
+}
+
+void FGameLiftMetricsModule::CrashHandler(const FGenericCrashContext& GenericContext)
+{
+    UE_LOG(LogGameLiftMetrics, Log, TEXT("Server crashed, CrashHandler being called..."));
+
+    const UGameLiftMetricsConfig& Config = UGameLiftMetricsConfig::Get();
+    if (!Config.bEnableMetrics)
+    {
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Metrics disabled: Skipping crash metrics"));
+        return;
+    }
+
+    if (!CurrentGameSessionId.IsEmpty())
+    {
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Incrementing crash metrics for session: %s"), *CurrentGameSessionId);
+        GAMELIFT_METRICS_INCREMENT(MetricServerCrashes);
+        GAMELIFT_METRICS_TAG_SET(MetricServerCrashes, "game_session_id", TCHAR_TO_UTF8(*CurrentGameSessionId));
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Crash metrics incremented"));
+
+        // Force process the metrics
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Sending crash metrics..."));
+        Aws::GameLift::Metrics::MetricsProcess();
+
+        // Small sleep to allow the metrics to be sent
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Waiting for metrics to send..."));
+        FPlatformProcess::Sleep(0.2f);
+
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Crash metrics incremented and processed"));
+    }
+    else
+    {
+        UE_LOG(LogGameLiftMetrics, Warning, TEXT("Server crashed with no active game session"));
+    }
+}
+
+bool FGameLiftMetricsModule::SetMetricsEnabled(bool bEnable)
+{
+    if (GIsEditor)
+    {
+        UE_LOG(LogGameLiftMetrics, Warning, TEXT("Cannot enable/disable metrics in editor - only applicable in game server"));
+        return false;
+    }
+
+    // If the state is already what's requested, no change needed
+    if (bEnable == bMetricsRunning)
+    {
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Metrics already %s, no change needed"),
+            bEnable ? TEXT("enabled") : TEXT("disabled"));
+        return true;
+    }
+    // Get current configuration and check current state
+    UGameLiftMetricsConfig* Config = const_cast<UGameLiftMetricsConfig*>(&UGameLiftMetricsConfig::Get());
+
+    if (bEnable)
+    {
+        // Enable metrics
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Enabling GameLift metrics at runtime"));
+
+        // Initialize with default parameters
+        Initialize();
+
+        // Flag is set inside Initialize method based on success
+        return bMetricsRunning;
+    }
+    else
+    {
+        // Disable metrics
+        UE_LOG(LogGameLiftMetrics, Log, TEXT("Disabling GameLift metrics at runtime"));
+
+        // Terminate metrics system
+        Terminate();
+        Config->bEnableMetrics = false;
+        bMetricsRunning = false;
+        return true;
+    }
+}
+
+bool FGameLiftMetricsModule::IsMetricsEnabled() const
+{
+    return bMetricsRunning;
+}
+
+#else
+
+void FGameLiftMetricsModule::StartupModule() {}
+void FGameLiftMetricsModule::ShutdownModule() {}
+void FGameLiftMetricsModule::Initialize() {}
+void FGameLiftMetricsModule::Initialize(const FMetricsParameters& metricsParameters) {}
+void FGameLiftMetricsModule::Terminate() {}
+void FGameLiftMetricsModule::OnStartGameSession(const Aws::GameLift::Server::Model::GameSession& Session) {}
+void FGameLiftMetricsModule::OnAcceptPlayerSession() {}
+void FGameLiftMetricsModule::OnRemovePlayerSession() {}
+void FGameLiftMetricsModule::ReEmitMetrics() {}
+bool FGameLiftMetricsModule::SetMetricsEnabled(bool bEnable) { return false; }
+bool FGameLiftMetricsModule::IsMetricsEnabled() const { return false; }
+
+#endif // WITH_GAMELIFT_METRICS
+
+IMPLEMENT_MODULE(FGameLiftMetricsModule, GameLiftMetrics)

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/GameLiftMetricsConfig.cpp

@@ -0,0 +1,21 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include "GameLiftMetricsConfig.h"
+
+
+const UGameLiftMetricsConfig& UGameLiftMetricsConfig::Get()
+{
+    UGameLiftMetricsConfig* CDO = Cast<UGameLiftMetricsConfig>(StaticClass()->GetDefaultObject());
+    check(IsValid(CDO));
+    return *CDO;
+}

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/GameLiftMetricsTypes.cpp

@@ -0,0 +1,15 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include "GameLiftMetricsTypes.h"
+
+DEFINE_LOG_CATEGORY(LogGameLiftMetrics);

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/MemoryStats.cpp

@@ -0,0 +1,42 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include "MemoryStats.h"
+
+#include "Engine.h"
+#include "EngineStats.h"
+
+namespace Aws {
+namespace GameLift {
+namespace Metrics {
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricMemoryPhysicalTotal);
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricMemoryPhysicalAvailable);
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricMemoryPhysicalUsed);
+
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricMemoryVirtualTotal);
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricMemoryVirtualAvailable);
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricMemoryVirtualUsed);
+}
+}
+}
+
+void FMemoryStats::Collect()
+{
+    auto MemoryStats = FPlatformMemory::GetStats();
+
+    GAMELIFT_METRICS_SET(Aws::GameLift::Metrics::MetricMemoryPhysicalTotal, MemoryStats.TotalPhysical);
+    GAMELIFT_METRICS_SET(Aws::GameLift::Metrics::MetricMemoryPhysicalAvailable, MemoryStats.AvailablePhysical);
+    GAMELIFT_METRICS_SET(Aws::GameLift::Metrics::MetricMemoryPhysicalUsed, MemoryStats.UsedPhysical);
+    GAMELIFT_METRICS_SET(Aws::GameLift::Metrics::MetricMemoryVirtualTotal, MemoryStats.TotalVirtual);
+    GAMELIFT_METRICS_SET(Aws::GameLift::Metrics::MetricMemoryVirtualAvailable, MemoryStats.AvailableVirtual);
+    GAMELIFT_METRICS_SET(Aws::GameLift::Metrics::MetricMemoryVirtualUsed, MemoryStats.UsedVirtual);
+}

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/MemoryStats.h

@@ -0,0 +1,35 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#pragma once
+
+#include "GameLiftMetricsTypes.h"
+
+namespace Aws {
+namespace GameLift {
+namespace Metrics {
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricMemoryPhysicalTotal, "server_mem_physical_total", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricMemoryPhysicalAvailable, "server_mem_physical_available", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricMemoryPhysicalUsed, "server_mem_physical_used", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricMemoryVirtualTotal, "server_mem_virtual_total", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricMemoryVirtualAvailable, "server_mem_virtual_available", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricMemoryVirtualUsed, "server_mem_virtual_used", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+}
+}
+}
+
+class FMemoryStats
+{
+public:
+    void Collect();
+};

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/NetworkStats.cpp

@@ -0,0 +1,106 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include "NetworkStats.h"
+
+#include "Engine/NetDriver.h"
+#include "Engine.h"
+
+namespace Aws {
+namespace GameLift {
+namespace Metrics {
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricConnectionCount);
+
+    GAMELIFT_METRICS_DEFINE_COUNTER(MetricBytesIn);
+    GAMELIFT_METRICS_DEFINE_COUNTER(MetricBytesOut);
+    GAMELIFT_METRICS_DEFINE_COUNTER(MetricPacketsIn);
+    GAMELIFT_METRICS_DEFINE_COUNTER(MetricPacketsInLost);
+    GAMELIFT_METRICS_DEFINE_COUNTER(MetricPacketsOut);
+    GAMELIFT_METRICS_DEFINE_COUNTER(MetricPacketsOutLost);
+}
+}
+}
+
+FNetworkStats::FNetworkStats()
+{
+    if (auto NetDriver = GetNetDriver())
+    {
+        LastInBytes = NetDriver->InTotalBytes;
+        LastOutBytes = NetDriver->OutTotalBytes;
+        LastInPackets = NetDriver->InTotalPackets;
+        LastOutPackets = NetDriver->OutTotalPackets;
+        LastInPacketsLost = NetDriver->InTotalPacketsLost;
+        LastOutPacketsLost = NetDriver->OutTotalPacketsLost;
+    }
+}
+
+void FNetworkStats::Collect()
+{
+    if (auto NetDriver = GetNetDriver())
+    {
+        GAMELIFT_METRICS_ADD(Aws::GameLift::Metrics::MetricBytesIn, NetDriver->InTotalBytes - LastInBytes);
+        GAMELIFT_METRICS_ADD(Aws::GameLift::Metrics::MetricBytesOut, NetDriver->OutTotalBytes - LastOutBytes);
+        GAMELIFT_METRICS_ADD(Aws::GameLift::Metrics::MetricPacketsIn, NetDriver->InTotalPackets - LastInPackets);
+        GAMELIFT_METRICS_ADD(Aws::GameLift::Metrics::MetricPacketsOut, NetDriver->OutTotalPackets - LastOutPackets);
+        GAMELIFT_METRICS_ADD(Aws::GameLift::Metrics::MetricPacketsInLost, NetDriver->InTotalPacketsLost - LastInPacketsLost);
+        GAMELIFT_METRICS_ADD(Aws::GameLift::Metrics::MetricPacketsOutLost, NetDriver->OutTotalPacketsLost - LastOutPacketsLost);
+
+        LastInBytes = NetDriver->InTotalBytes;
+        LastOutBytes = NetDriver->OutTotalBytes;
+        LastInPackets = NetDriver->InTotalPackets;
+        LastOutPackets = NetDriver->OutTotalPackets;
+        LastInPacketsLost = NetDriver->InTotalPacketsLost;
+        LastOutPacketsLost = NetDriver->OutTotalPacketsLost;
+
+        GAMELIFT_METRICS_SET(Aws::GameLift::Metrics::MetricConnectionCount, NetDriver->ClientConnections.Num());
+    }
+    else
+    {
+        UE_LOG(LogGameLiftMetrics, Error, TEXT("Net driver is null. Cannot log network metrics."));
+    }
+}
+
+const UNetDriver* FNetworkStats::GetNetDriver() const
+{
+    UEngine* Engine = GEngine;
+    if (!IsValid(Engine))
+    {
+        UE_LOG(LogGameLiftMetrics, Error, TEXT("Engine pointer is not valid when retrieving net driver."));
+        return nullptr;
+    }
+
+    const auto& WorldContexts = Engine->GetWorldContexts();
+    if (WorldContexts.Num() == 0)
+    {
+        // no worlds are loaded
+        // generally can only be true before everything is fully initialized
+        UE_LOG(LogGameLiftMetrics, Error, TEXT("No world is loaded when retrieving net driver."));
+        return nullptr;
+    }
+
+    // Only one world context should be present outside Editor.
+    // (editor has multiple)
+    // Refer to FWorldContext comment in Engine.h
+    const FWorldContext& WorldContext = WorldContexts[0];
+    check(WorldContext.WorldType == EWorldType::Game);
+
+    // In theory multiple net drivers might be present.
+    // One will be for gameplay but additional ones might be opened for non-gameplay traffic.
+    // Might be null during initialisation.
+    if (WorldContext.ActiveNetDrivers.Num() == 0)
+    {
+        UE_LOG(LogGameLiftMetrics, Error, TEXT("No active net drivers. Cannot acquire network metrics."));
+        return nullptr;
+    }
+
+    return WorldContext.ActiveNetDrivers[0].NetDriver;
+}

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/NetworkStats.h

@@ -0,0 +1,53 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#pragma once
+
+#include "GameLiftMetricsTypes.h"
+
+class UNetDriver;
+
+namespace Aws {
+namespace GameLift {
+namespace Metrics {
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricConnectionCount, "server_connections", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+
+    GAMELIFT_METRICS_DECLARE_COUNTER(MetricBytesIn, "server_bytes_in", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DECLARE_COUNTER(MetricBytesOut, "server_bytes_out", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+
+    GAMELIFT_METRICS_DECLARE_COUNTER(MetricPacketsIn, "server_packets_in", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DECLARE_COUNTER(MetricPacketsInLost, "server_packets_in_lost", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+
+    GAMELIFT_METRICS_DECLARE_COUNTER(MetricPacketsOut, "server_packets_out", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+    GAMELIFT_METRICS_DECLARE_COUNTER(MetricPacketsOutLost, "server_packets_out_lost", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+}
+}
+}
+
+class FNetworkStats
+{
+public:
+    FNetworkStats();
+
+    void Collect();
+
+private:
+    const UNetDriver* GetNetDriver() const;
+
+private:
+    int32 LastInBytes = 0;
+    int32 LastOutBytes = 0;
+    int32 LastInPackets = 0;
+    int32 LastOutPackets = 0;
+    int32 LastInPacketsLost = 0;
+    int32 LastOutPacketsLost = 0;
+};

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/TickableCollector.cpp

@@ -0,0 +1,57 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include "TickableCollector.h"
+#include "TimeStats.h"
+#include "GameLiftMetrics.h"
+
+#include "Misc/App.h"
+
+namespace Aws {
+namespace GameLift {
+namespace Metrics {
+    GAMELIFT_METRICS_DEFINE_GAUGE(MetricServerUp);
+}
+}
+}
+
+#if WITH_GAMELIFT_METRICS
+void FTickableCollector::Tick(float)
+{
+    GAMELIFT_METRICS_SET(Aws::GameLift::Metrics::MetricServerUp, 1);
+
+    NetworkStats.Collect();
+    MemoryStats.Collect();
+
+    const double DeltaTime = FApp::GetDeltaTime();
+    GAMELIFT_METRICS_SET_SEC(Aws::GameLift::Metrics::MetricGameDeltaTime, DeltaTime);
+    if (bComputeFallbackGameThreadTime)
+    {
+        const double EstimatedGameThreadTime = DeltaTime - FApp::GetIdleTime();
+        GAMELIFT_METRICS_SET_SEC(Aws::GameLift::Metrics::MetricGameTickTime, EstimatedGameThreadTime);
+    }
+
+    // Re-emit specific metrics so that they don't go stale.
+    // Grafana reports no data for the metric after 5 minutes of it being stale.
+    FGameLiftMetricsModule::Get().ReEmitMetrics();
+
+    Aws::GameLift::Metrics::MetricsProcess();
+}
+#else
+void FTickableCollector::Tick(float) {}
+#endif // WITH_GAMELIFT_METRICS
+
+
+TStatId FTickableCollector::GetStatId() const
+{
+    return TStatId{};
+}

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/TickableCollector.h

@@ -0,0 +1,53 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Tickable.h"
+
+#include "GameLiftMetricsTypes.h"
+
+#include "NetworkStats.h"
+#include "MemoryStats.h"
+
+
+namespace Aws {
+namespace GameLift {
+namespace Metrics {
+    GAMELIFT_METRICS_DECLARE_GAUGE(MetricServerUp, "server_up", Aws::GameLift::Metrics::Server, Aws::GameLift::Metrics::SampleAll());
+}
+}
+}
+
+class FTickableCollector : public FTickableGameObject
+{
+public:
+    FTickableCollector(bool bComputeFallbackGameThreadTime)
+        : bComputeFallbackGameThreadTime(bComputeFallbackGameThreadTime) {}
+
+    // FTickableGameObject
+    virtual void Tick(float) override;
+
+    virtual bool IsTickable() const override { return true; }
+
+    virtual bool IsTickableWhenPaused() const override { return true; }
+    virtual bool IsTickableInEditor() const override { return false; }
+    virtual ETickableTickType GetTickableTickType() const override { return ETickableTickType::Always; }
+    virtual TStatId GetStatId() const override;
+    // ~FTickableGameObject
+
+private:
+    bool bComputeFallbackGameThreadTime = false;
+    FNetworkStats NetworkStats;
+    FMemoryStats MemoryStats;
+};

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/TimeStats.cpp

@@ -0,0 +1,24 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include "TimeStats.h"
+
+namespace Aws {
+namespace GameLift {
+namespace Metrics {
+    GAMELIFT_METRICS_DEFINE_TIMER(MetricGameDeltaTime);
+
+    GAMELIFT_METRICS_DEFINE_TIMER(MetricGameTickTime);
+    GAMELIFT_METRICS_DEFINE_TIMER(MetricWorldTickTime);
+}
+}
+}

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/TimeStats.h

@@ -0,0 +1,74 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#pragma once
+
+#include "GameLiftMetricsTypes.h"
+
+namespace Aws {
+namespace GameLift {
+namespace Metrics {
+    /**
+     * Server time-step in milliseconds.
+     *
+     * This is the time between consecutive ticks.
+     *
+     * When the server is under performing, this will exceed the target tick rate,
+     * otherwise it should hover in its vicinity.
+     *
+     * To compute the tick rate, compute the reciprocal: (1000 / server_delta_time)
+     */
+    GAMELIFT_METRICS_DECLARE_TIMER(
+        MetricGameDeltaTime, "server_delta_time",
+        Aws::GameLift::Metrics::Server,
+        Aws::GameLift::Metrics::SampleAll(),
+        Aws::GameLift::Metrics::Percentiles(0.5, 0.9, 0.95)
+    );
+
+    /**
+     * The time it takes to process a single tick.
+     *
+     * A subset of delta time.
+     * server_tick_time <= server_delta_time at all times. Typically (much) smaller.
+     *
+     * This is the time it takes to actually process the tick. The remaining
+     * time-step duration is spent waiting for the next tick.
+     */
+    GAMELIFT_METRICS_DECLARE_TIMER(
+        MetricGameTickTime, "server_tick_time",
+        Aws::GameLift::Metrics::Server,
+        Aws::GameLift::Metrics::SampleAll(),
+        Aws::GameLift::Metrics::Percentiles(0.5, 0.9, 0.95)
+    );
+
+    /**
+     * The time it takes to process the world update.
+     *
+     * A subset of tick time.
+     *
+     * This is the time it takes to process the Actors and Blueprints in the
+     * currently loaded Map. The remainder of server_tick_time is spent in
+     * other engine subsystems like network replication or physics.
+     *
+     * Only available in Debug or Development builds, or Shipping builds with
+     * USE_FORCE_STATS=1.
+     */
+    GAMELIFT_METRICS_DECLARE_TIMER(
+        MetricWorldTickTime,
+       "server_world_tick_time",
+       Aws::GameLift::Metrics::Server,
+       Aws::GameLift::Metrics::SampleAll(),
+       Aws::GameLift::Metrics::Percentiles(0.5, 0.9, 0.95)
+    );
+}
+}
+}

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/UnrealStatCollector.cpp

@@ -0,0 +1,136 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include "UnrealStatCollector.h"
+
+#include "Runtime/Launch/Resources/Version.h"
+
+#include "TimeStats.h"
+
+#include "Async/TaskGraphInterfaces.h"
+#include "Stats/Stats.h"
+#include "Stats/StatsData.h"
+#include "EngineStats.h"
+
+
+#if STATS
+namespace
+{
+#if ENGINE_MAJOR_VERSION >= 5
+    void IncrementStatsRefCount()
+    {
+        StatsPrimaryEnableAdd();
+    }
+
+    void DecrementStatsRefCount()
+    {
+        StatsPrimaryEnableSubtract();
+    }
+#else
+    void IncrementStatsRefCount()
+    {
+        StatsMasterEnableAdd();
+    }
+
+    void DecrementStatsRefCount()
+    {
+        StatsMasterEnableSubtract();
+    }
+#endif
+}
+
+void FUnrealStatCollector::Subscribe()
+{
+    IncrementStatsRefCount();
+
+/*
+ * From 5.2.0 onwards, UE_STATS_THREAD_AS_PIPE is undefined and the only way to
+ * access the stat system is via the new API.
+ *
+ * Between 5.0.0 and 5.2.0, UE_STATS_THREAD_AS_PIPE enables new API. If it is 0,
+ * the old API can be used.
+ *
+ * See UE engine source commits 10b5e05d00df4f23d3b75f6af5ec08f8ae0e8618
+ *                              327a94d1a4e021714f2c3ca820fe9ed5606465bf
+ *                              d48f6660b807c7377926cffd12020645f91772f8
+ *
+ * All references to UE_STATS_THREAD_AS_PIPE are removed in
+ * d48f6660b807c7377926cffd12020645f91772f8.
+ */
+#if ENGINE_MAJOR_VERSION >= 5 && (ENGINE_MINOR_VERSION >= 2 || UE_STATS_THREAD_AS_PIPE)
+    {
+        auto& StatsState = FStatsThreadState::GetLocalState();
+        StatsState.NewFrameDelegate.AddSP(this, &FUnrealStatCollector::OnNewFrame);
+    }
+#else
+    FSimpleDelegateGraphTask::CreateAndDispatchWhenReady
+    (
+        FSimpleDelegateGraphTask::FDelegate::CreateLambda(
+            [WeakCollector = TWeakPtr<FUnrealStatCollector>(this->AsShared())]() {
+                if (!WeakCollector.IsValid()) { return; }
+
+                auto& StatsState = FStatsThreadState::GetLocalState();
+                StatsState.NewFrameDelegate.AddSP(WeakCollector.Pin().Get(), &FUnrealStatCollector::OnNewFrame);
+            }
+        ),
+        TStatId{},
+        nullptr,
+        /*
+         * StatsThread is deprecated since 5.0
+         *
+         * Need to verify post-5.0 behaviour but:
+         * - 4.27 to 5.0 should use the current method to subscribe to NewFrameDelegate
+         * - 5.0 on can subscribe from game thread directly. (See FThreadStats::bUseThreadAsPipe)
+         */
+        ENamedThreads::StatsThread
+    );
+#endif // UE_STATS_THREAD_AS_PIPE
+}
+
+void FUnrealStatCollector::Unsubscribe()
+{
+    DecrementStatsRefCount();
+}
+
+void FUnrealStatCollector::OnNewFrame(int64 Frame)
+{
+    TArray<FStatMessage> OutStats;
+
+    auto& Stats = FStatsThreadState::GetLocalState();
+    Stats.GetInclusiveAggregateStackStats(Frame, OutStats);
+
+    for (auto& Message : OutStats)
+    {
+        // GetShortName() is expensive and we're calling it for every stat.
+        // In practice: we'll stick filter by GetRawName first and stick things in a hashmap
+        //              might also be able to compare FName indices
+        FName ShortName = Message.NameAndInfo.GetShortName();
+
+        // Robustness: we can check the value type from message before blindly grabbing duration (or other types)
+
+        // Consult EngineStats.h for stat names
+        // (There's also many other stats in other subsystems.)
+        if (ShortName == TEXT("STAT_GameEngineTick"))
+        {
+            GAMELIFT_METRICS_SET_MS(Aws::GameLift::Metrics::MetricGameTickTime, FPlatformTime::ToMilliseconds(Message.GetValue_Duration()));
+        }
+        else if (ShortName == TEXT("STAT_WorldTickTime"))
+        {
+            GAMELIFT_METRICS_SET_MS(Aws::GameLift::Metrics::MetricWorldTickTime, FPlatformTime::ToMilliseconds(Message.GetValue_Duration()));
+        }
+    }
+}
+#else
+void FUnrealStatCollector::Subscribe() {}
+void FUnrealStatCollector::Unsubscribe() {}
+void FUnrealStatCollector::OnNewFrame(int64 Frame) {}
+#endif // STATS

Plugins/GameLiftServerSDK/Source/GameLiftMetrics/Private/UnrealStatCollector.h

@@ -0,0 +1,31 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#pragma once
+
+#include "CoreMinimal.h"
+
+class FUnrealStatCollector : public TSharedFromThis<FUnrealStatCollector>
+{
+public:
+    /**
+     * Subscribes to NewFrameDelegate in Unreal stats system.
+     */
+    void Subscribe();
+
+    /**
+     * Unsubscribes from NewFrameDelegate in Unreal stats system.
+     */
+    void Unsubscribe();
+
+    void OnNewFrame(int64 Frame);
+};