Asset Processor: Remove gem loading from AP (#6488)

* AssetBuilder sends builder registration network message to AP

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Add AP activating status message

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* First builder handles registration.

Fixed deadlock caused by AP and AssetBuilder waiting on each other when registering by moving AP builder start code to a thread

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Clean up external builder registration

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Add thread description for builder manager idle thread

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Remove gem loading

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Clean up builder registration and remove unused functions

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Remove PostActivate call from batch application since it will be called after builders are registered

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Removal external builder dependency scanning since we no longer support builder dlls

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Fix missing bus disconnect

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Remove unused variable

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

* Moved AP-AssetBuilder specific types into AssetBuilder.Static library.  Also removed some unused/old code

Signed-off-by: amzn-mike <80125227+amzn-mike@users.noreply.github.com>

Code/Tools/AssetProcessor/native/assetprocessor.h

@@ -85,7 +85,7 @@ namespace AssetProcessor
 
     enum AssetCatalogStatus
     {
-        RequiresSaving, 
+        RequiresSaving,
         UpToDate
     };
 
@@ -213,11 +213,11 @@ namespace AssetProcessor
 
         bool m_critical = false;
         int m_priority = -1;
-        // indicates whether we need to check the server first for the outputs of this job 
+        // indicates whether we need to check the server first for the outputs of this job
         // before we start processing locally
         bool m_checkServer = false;
-         
-        // Indicates whether this job needs to be processed irrespective of whether its fingerprint got modified or not. 
+
+        // Indicates whether this job needs to be processed irrespective of whether its fingerprint got modified or not.
         bool m_autoProcessJob = false;
 
         AssetBuilderSDK::AssetBuilderDesc   m_assetBuilderDesc;
@@ -251,9 +251,9 @@ namespace AssetProcessor
 
         JobDetails() = default;
     };
- 
-    //! JobDesc struct is used for identifying jobs that need to be processed again 
-    //! because of job dependency declared on them by other jobs  
+
+    //! JobDesc struct is used for identifying jobs that need to be processed again
+    //! because of job dependency declared on them by other jobs
     struct JobDesc
     {
         AZStd::string m_databaseSourceName;
@@ -283,7 +283,7 @@ namespace AssetProcessor
         }
     };
 
-    //! JobIndentifier is an internal structure that store all the data that can uniquely identify a job 
+    //! JobIndentifier is an internal structure that store all the data that can uniquely identify a job
     struct JobIndentifier
     {
         JobDesc m_jobDesc;

Code/Tools/AssetProcessor/native/ui/MainWindow.cpp

@@ -165,7 +165,7 @@ void MainWindow::Activate()
     ui->connectionTreeView->header()->resizeSection(ConnectionManager::PortColumn, 60);
     ui->connectionTreeView->header()->resizeSection(ConnectionManager::PlatformColumn, 60);
     ui->connectionTreeView->header()->resizeSection(ConnectionManager::AutoConnectColumn, 60);
-    
+
     ui->connectionTreeView->header()->setStretchLastSection(false);
     connect(ui->connectionTreeView->selectionModel(), &QItemSelectionModel::selectionChanged, this, &MainWindow::OnConnectionSelectionChanged);
 
@@ -189,12 +189,12 @@ void MainWindow::Activate()
     ui->allowListAllowedListConnectionsListView->setModel(&m_allowedListAddresses);
     connect(ui->allowedListRejectedConnectionsListView, &QListView::clicked, this, &MainWindow::OnRejectedConnectionsListViewClicked);
     ui->allowedListRejectedConnectionsListView->setModel(&m_rejectedAddresses);
-    
+
     connect(ui->allowedListEnableCheckBox, &QCheckBox::toggled, this, &MainWindow::OnAllowedListCheckBoxToggled);
-    
+
     connect(ui->allowedListAddHostNameToolButton, &QToolButton::clicked, this, &MainWindow::OnAddHostNameAllowedListButtonClicked);
     connect(ui->allowedListAddIPToolButton, &QPushButton::clicked, this, &MainWindow::OnAddIPAllowedListButtonClicked);
-    
+
     connect(ui->allowedListToAllowedListToolButton, &QPushButton::clicked, this, &MainWindow::OnToAllowedListButtonClicked);
     connect(ui->allowedListToRejectedListToolButton, &QToolButton::clicked, this, &MainWindow::OnToRejectedListButtonClicked);
 
@@ -204,7 +204,7 @@ void MainWindow::Activate()
 
     QRegExpValidator* hostNameValidator = new QRegExpValidator(validHostName, this);
     ui->allowedListAddHostNameLineEdit->setValidator(hostNameValidator);
-    
+
     QRegExpValidator* ipValidator = new QRegExpValidator(validIP, this);
     ui->allowedListAddIPLineEdit->setValidator(ipValidator);
 
@@ -235,7 +235,7 @@ void MainWindow::Activate()
     m_logSortFilterProxy->setSourceModel(m_logsModel);
     m_logSortFilterProxy->setFilterKeyColumn(AzToolsFramework::Logging::LogTableModel::ColumnMessage);
     m_logSortFilterProxy->setFilterCaseSensitivity(Qt::CaseInsensitive);
-    
+
     ui->jobLogTableView->setModel(m_logSortFilterProxy);
     ui->jobLogTableView->setItemDelegate(new AzToolsFramework::Logging::LogTableItemDelegate(ui->jobLogTableView));
     ui->jobLogTableView->setExpandOnSelection();
@@ -400,7 +400,7 @@ void MainWindow::Activate()
     bool zeroAnalysisModeFromSettings = settings.value("EnableZeroAnalysis", QVariant(true)).toBool();
     settings.endGroup();
 
-    QObject::connect(ui->modtimeSkippingCheckBox, &QCheckBox::stateChanged, this, 
+    QObject::connect(ui->modtimeSkippingCheckBox, &QCheckBox::stateChanged, this,
         [this](int newCheckState)
     {
         bool newOption = newCheckState == Qt::Checked ? true : false;
@@ -543,7 +543,7 @@ void MainWindow::OnAddConnection(bool /*checked*/)
     m_guiApplicationManager->GetConnectionManager()->addUserConnection();
 }
 
-void MainWindow::OnAllowedListConnectionsListViewClicked() 
+void MainWindow::OnAllowedListConnectionsListViewClicked()
 {
     ui->allowedListRejectedConnectionsListView->clearSelection();
 }
@@ -553,7 +553,7 @@ void MainWindow::OnRejectedConnectionsListViewClicked()
     ui->allowListAllowedListConnectionsListView->clearSelection();
 }
 
-void MainWindow::OnAllowedListCheckBoxToggled() 
+void MainWindow::OnAllowedListCheckBoxToggled()
 {
     if (!ui->allowedListEnableCheckBox->isChecked())
     {
@@ -588,7 +588,7 @@ void MainWindow::OnAllowedListCheckBoxToggled()
         ui->allowedListToAllowedListToolButton->setEnabled(true);
         ui->allowedListToRejectedListToolButton->setEnabled(true);
     }
-    
+
     m_guiApplicationManager->GetConnectionManager()->AllowedListingEnabled(ui->allowedListEnableCheckBox->isChecked());
 }
 
@@ -858,7 +858,7 @@ void MainWindow::OnAssetProcessorStatusChanged(const AssetProcessor::AssetProces
             text = tr("Working, analyzing jobs remaining %1, processing jobs remaining %2...").arg(m_createJobCount).arg(m_processJobsCount);
             ui->timerContainerWidget->setVisible(false);
             ui->productAssetDetailsPanel->SetScanQueueEnabled(false);
-            
+
             IntervalAssetTabFilterRefresh();
         }
         else
@@ -877,7 +877,7 @@ void MainWindow::OnAssetProcessorStatusChanged(const AssetProcessor::AssetProces
         break;
     case AssetProcessorStatus::Processing_Jobs:
         CheckStartProcessTimers();
-        m_processJobsCount = entry.m_count;  
+        m_processJobsCount = entry.m_count;
 
         if (m_processJobsCount + m_createJobCount > 0)
         {
@@ -983,7 +983,7 @@ void MainWindow::ApplyConfig()
     ui->jobLogTableView->header()->resizeSection(AzToolsFramework::Logging::LogTableModel::ColumnType, m_config.logTypeColumnWidth);
 }
 
-MainWindow::LogSortFilterProxy::LogSortFilterProxy(QObject* parentOjbect) : QSortFilterProxyModel(parentOjbect) 
+MainWindow::LogSortFilterProxy::LogSortFilterProxy(QObject* parentOjbect) : QSortFilterProxyModel(parentOjbect)
 {
 }
 
@@ -1302,7 +1302,7 @@ void MainWindow::ShowJobViewContextMenu(const QPoint& pos)
         ui->sourceAssetDetailsPanel->GoToSource(item->m_elementId.GetInputAssetName().toUtf8().constData());
     });
 
-    QString productMenuTitle(tr("View product asset..."));        
+    QString productMenuTitle(tr("View product asset..."));
     if (item->m_jobState != AzToolsFramework::AssetSystem::JobStatus::Completed)
     {
         QString disabledActionTooltip(tr("Only completed jobs are available in the Assets tab."));
@@ -1610,7 +1610,7 @@ void MainWindow::ShowProductAssetContextMenu(const QPoint& pos)
         {
             AzQtComponents::ShowFileOnDesktop(pathToProduct.GetValue());
         }
-        
+
     });
 
     QString fileOrFolder(cachedAsset->getChildCount() > 0 ? tr("folder") : tr("file"));

Code/Tools/AssetProcessor/native/utilities/ApplicationManager.cpp

@@ -231,44 +231,6 @@ bool ApplicationManager::InitiatedShutdown() const
     return m_duringShutdown;
 }
 
-void ApplicationManager::GetExternalBuilderFileList(QStringList& externalBuilderModules)
-{
-    externalBuilderModules.clear();
-
-    static const char* builder_folder_name = "Builders";
-
-    // LY_ASSET_BUILDERS is defined by the CMakeLists.txt. The asset builders add themselves to a variable that
-    // is populated to allow selective building of those asset builder targets.
-    // This allows left over Asset builders in the output directory to not be loaded by the AssetProcessor
-#if !defined(LY_ASSET_BUILDERS)
-    #error LY_ASSET_BUILDERS was not defined for ApplicationManager.cpp
-#endif
-
-    QDir builderDir = QDir::toNativeSeparators(QString(this->m_frameworkApp.GetExecutableFolder()));
-    builderDir.cd(QString(builder_folder_name));
-    if (builderDir.exists())
-    {
-        AZStd::vector<AZStd::string> tokens;
-        AZ::StringFunc::Tokenize(AZStd::string_view(LY_ASSET_BUILDERS), tokens, ',');
-        AZStd::string builderLibrary;
-        for (const AZStd::string& token : tokens)
-        {
-            QString assetBuilderPath(token.c_str());
-            if (builderDir.exists(assetBuilderPath))
-            {
-                externalBuilderModules.push_back(builderDir.absoluteFilePath(assetBuilderPath));
-            }
-        }
-    }
-
-    if (externalBuilderModules.empty())
-    {
-        AZ_TracePrintf(AssetProcessor::ConsoleChannel, "AssetProcessor was unable to locate any external builders\n");
-    }
-}
-
-
-
 QDir ApplicationManager::GetSystemRoot() const
 {
     return m_systemRoot;
@@ -459,15 +421,6 @@ void ApplicationManager::PopulateApplicationDependencies()
         m_filesOfInterest.push_back(dir.absoluteFilePath(pathWithPlatformExtension));
     }
 
-    // Get the external builder modules to add to the files of interest
-    QStringList builderModuleFileList;
-    GetExternalBuilderFileList(builderModuleFileList);
-    for (const QString& builderModuleFile : builderModuleFileList)
-    {
-        m_filesOfInterest.push_back(builderModuleFile);
-    }
-
-
     QDir assetRoot;
     AssetUtilities::ComputeAssetRoot(assetRoot);
 

Code/Tools/AssetProcessor/native/utilities/ApplicationManager.h

@@ -139,7 +139,7 @@ protected:
     void RegisterObjectForQuit(QObject* source, bool insertInFront = false);
     bool NeedRestart() const;
     void addRunningThread(AssetProcessor::ThreadWorker* thread);
-    
+
     template<class BuilderClass>
     void RegisterInternalBuilder(const QString& builderName);
 
@@ -151,9 +151,6 @@ protected:
     bool m_duringStartup = true;
     AssetProcessorAZApplication m_frameworkApp;
     QCoreApplication* m_qApp = nullptr;
-    
-    //! Get the list of external builder files for this asset processor
-    void GetExternalBuilderFileList(QStringList& externalBuilderModules);
 
     virtual void Reflect() = 0;
     virtual const char* GetLogBaseName() = 0;

Code/Tools/AssetProcessor/native/utilities/ApplicationManagerBase.cpp

@@ -25,6 +25,7 @@
 #include <native/InternalBuilders/SettingsRegistryBuilder.h>
 #include <AzToolsFramework/Application/Ticker.h>
 #include <AzToolsFramework/ToolsFileUtils/ToolsFileUtils.h>
+#include <AssetBuilder/AssetBuilderStatic.h>
 
 #include <iostream>
 
@@ -32,9 +33,6 @@
 
 #include <QElapsedTimer>
 
-//! Amount of time to wait between checking the status of the AssetBuilder process
-static const int s_MaximumSleepTimeMS = 10;
-
 //! CreateJobs will wait up to 2 minutes before timing out
 //! This shouldn't need to be so high but very large slices can take a while to process currently
 //! This should be reduced down to something more reasonable after slice jobs are sped up
@@ -64,6 +62,7 @@ ApplicationManagerBase::~ApplicationManagerBase()
     AZ::Debug::TraceMessageBus::Handler::BusDisconnect();
     AssetProcessor::AssetBuilderRegistrationBus::Handler::BusDisconnect();
     AssetBuilderSDK::AssetBuilderBus::Handler::BusDisconnect();
+    AssetProcessor::AssetBuilderInfoBus::Handler::BusDisconnect();
 
     if (m_settingsRegistryBuilder)
     {
@@ -192,7 +191,7 @@ void ApplicationManagerBase::InitAssetProcessorManager()
     {
         m_assetProcessorManager->SetEnableModtimeSkippingFeature(true);
     }
-    
+
     if (commandLine->HasSwitch(Command_enableQueryLogging.m_switch))
     {
         m_assetProcessorManager->SetQueryLogging(true);
@@ -206,7 +205,7 @@ void ApplicationManagerBase::InitAssetProcessorManager()
     {
         m_dependencyScanPattern = commandLine->GetSwitchValue(Command_dsp.m_switch, 0).c_str();
     }
-    
+
     m_fileDependencyScanPattern = "*";
 
     if (commandLine->HasSwitch(Command_fileDependencyScanPattern.m_switch))
@@ -327,7 +326,7 @@ void ApplicationManagerBase::InitAssetCatalog()
                 AssetProcessor::AssetCatalog* catalog = new AssetCatalog(assetCatalogHelper, m_platformConfiguration);
 
                 // Using a direct connection so we know the catalog has been updated before continuing on with code might depend on the asset being in the catalog
-                connect(m_assetProcessorManager, &AssetProcessorManager::AssetMessage, catalog, &AssetCatalog::OnAssetMessage, Qt::DirectConnection); 
+                connect(m_assetProcessorManager, &AssetProcessorManager::AssetMessage, catalog, &AssetCatalog::OnAssetMessage, Qt::DirectConnection);
                 connect(m_assetProcessorManager, &AssetProcessorManager::SourceQueued, catalog, &AssetCatalog::OnSourceQueued);
                 connect(m_assetProcessorManager, &AssetProcessorManager::SourceFinished, catalog, &AssetCatalog::OnSourceFinished);
                 connect(m_assetProcessorManager, &AssetProcessorManager::PathDependencyResolved, catalog, &AssetCatalog::OnDependencyResolved);
@@ -379,12 +378,12 @@ void ApplicationManagerBase::InitAssetScanner()
     QObject::connect(m_assetScanner, &AssetScanner::FilesFound, [this](QSet<AssetFileInfo> files) { m_fileStateCache->AddInfoSet(files); });
     QObject::connect(m_assetScanner, &AssetScanner::FoldersFound, [this](QSet<AssetFileInfo> files) { m_fileStateCache->AddInfoSet(files); });
     QObject::connect(m_assetScanner, &AssetScanner::ExcludedFound, [this](QSet<AssetFileInfo> files) { m_fileStateCache->AddInfoSet(files); });
-    
+
     // file table
     QObject::connect(m_assetScanner, &AssetScanner::AssetScanningStatusChanged, m_fileProcessor.get(), &FileProcessor::OnAssetScannerStatusChange);
     QObject::connect(m_assetScanner, &AssetScanner::FilesFound,                 m_fileProcessor.get(), &FileProcessor::AssessFilesFromScanner);
     QObject::connect(m_assetScanner, &AssetScanner::FoldersFound,               m_fileProcessor.get(), &FileProcessor::AssessFoldersFromScanner);
-    
+
 }
 
 void ApplicationManagerBase::DestroyAssetScanner()
@@ -591,6 +590,51 @@ void ApplicationManagerBase::InitConnectionManager()
             }, AZStd::placeholders::_1, AZStd::placeholders::_2, AZStd::placeholders::_3, AZStd::placeholders::_4)
         );
 
+    m_connectionManager->RegisterService(
+        AssetBuilder::BuilderRegistrationRequest::MessageType,
+        [this](unsigned int /*connId*/, unsigned int /*type*/, unsigned int /*serial*/, QByteArray payload, QString)
+    {
+        AssetBuilder::BuilderRegistrationRequest registrationRequest;
+
+        if (m_builderRegistrationComplete)
+        {
+            return;
+        }
+
+        m_builderRegistrationComplete = true;
+
+        if (AssetProcessor::UnpackMessage(payload, registrationRequest))
+        {
+            for (const auto& builder : registrationRequest.m_builders)
+            {
+                AssetBuilderSDK::AssetBuilderDesc desc;
+                desc.m_name = builder.m_name;
+                desc.m_patterns = builder.m_patterns;
+                desc.m_version = builder.m_version;
+                desc.m_analysisFingerprint = builder.m_analysisFingerprint;
+                desc.m_flags = builder.m_flags;
+                desc.m_busId = builder.m_busId;
+                desc.m_flagsByJobKey = builder.m_flagsByJobKey;
+                desc.m_productsToKeepOnFailure = builder.m_productsToKeepOnFailure;
+
+                // Builders registered this way are always external builders
+                desc.m_builderType = AssetBuilderSDK::AssetBuilderDesc::AssetBuilderType::External;
+
+                RegisterBuilderInformation(desc);
+            }
+
+            QTimer::singleShot(
+                0, this,
+                [this]()
+                {
+                    if (!PostActivate())
+                    {
+                        QuitRequested();
+                    }
+                });
+        }
+    });
+
     //You can get Asset Processor Current State
     using AzFramework::AssetSystem::RequestAssetProcessorStatus;
     auto GetState = [this](unsigned int connId, unsigned int, unsigned int serial, QByteArray payload, QString)
@@ -633,11 +677,11 @@ void ApplicationManagerBase::InitConnectionManager()
             AssetProcessorPlatformStatusRequest requestMessage;
             if (AssetProcessor::UnpackMessage(payload, requestMessage))
             {
-                AzToolsFramework::AssetSystemRequestBus::BroadcastResult(responseMessage.m_isPlatformEnabled, 
+                AzToolsFramework::AssetSystemRequestBus::BroadcastResult(responseMessage.m_isPlatformEnabled,
                         &AzToolsFramework::AssetSystemRequestBus::Events::IsAssetPlatformEnabled, requestMessage.m_platform.c_str());
             }
 
-            AssetProcessor::ConnectionBus::Event(connId, 
+            AssetProcessor::ConnectionBus::Event(connId,
                 &AssetProcessor::ConnectionBus::Events::SendResponse, serial, responseMessage);
         });
 
@@ -653,11 +697,11 @@ void ApplicationManagerBase::InitConnectionManager()
             if (AssetProcessor::UnpackMessage(payload, requestMessage))
             {
                 const char* platformIdentifier = requestMessage.m_platform.c_str();
-                responseMessage.m_numberOfPendingJobs = 
+                responseMessage.m_numberOfPendingJobs =
                     GetRCController()->NumberOfPendingJobsPerPlatform(platformIdentifier);
             }
 
-            AssetProcessor::ConnectionBus::Event(connId, 
+            AssetProcessor::ConnectionBus::Event(connId,
                 &AssetProcessor::ConnectionBus::Events::SendResponse, serial, responseMessage);
         });
 }
@@ -696,7 +740,7 @@ void ApplicationManagerBase::InitAssetRequestHandler(AssetProcessor::AssetReques
     QObject::connect(GetAssetProcessorManager(), &AssetProcessorManager::SendAssetExistsResponse, m_assetRequestHandler, &AssetRequestHandler::OnRequestAssetExistsResponse);
 
     QObject::connect(GetAssetProcessorManager(), &AssetProcessorManager::FenceFileDetected, m_assetRequestHandler, &AssetRequestHandler::OnFenceFileDetected);
-    
+
     // connect the Asset Request Handler to RC:
     QObject::connect(m_assetRequestHandler, &AssetRequestHandler::RequestCompileGroup, GetRCController(), &RCController::OnRequestCompileGroup);
     QObject::connect(m_assetRequestHandler, &AssetRequestHandler::RequestEscalateAssetBySearchTerm, GetRCController(), &RCController::OnEscalateJobsBySearchTerm);
@@ -840,14 +884,6 @@ bool ApplicationManagerBase::Run()
         return false;
     }
 
-    bool startedSuccessfully = true;
-
-    if (!PostActivate())
-    {
-        QuitRequested();
-        startedSuccessfully = false;
-    }
-
     AZ_Printf(AssetProcessor::ConsoleChannel, "Asset Processor Batch Processing Started.\n");
     AZ_Printf(AssetProcessor::ConsoleChannel, "-----------------------------------------\n");
     QElapsedTimer allAssetsProcessingTimer;
@@ -867,7 +903,7 @@ bool ApplicationManagerBase::Run()
     RemoveOldTempFolders();
     Destroy();
 
-    return (startedSuccessfully && FailedAssetsCount() == 0);
+    return FailedAssetsCount() == 0;
 }
 
 void ApplicationManagerBase::HandleFileRelocation() const
@@ -899,7 +935,7 @@ void ApplicationManagerBase::HandleFileRelocation() const
         while(!m_sourceControlReady)
         {
             // We need to wait for source control to be ready before continuing
-            
+
             if (printCounter % 10 == 0)
             {
                 AZ_TracePrintf(AssetProcessor::ConsoleChannel, "Waiting for Source Control connection\n");
@@ -1129,7 +1165,7 @@ void ApplicationManagerBase::CheckForIdle()
             TryScanProductDependencies();
 
             TryHandleFileRelocation();
-            
+
             // since we are shutting down, we save the registry and then we quit.
             AZ_Printf(AssetProcessor::ConsoleChannel, "No assets remain in the build queue.  Saving the catalog, and then shutting down.\n");
             // stop accepting any further idle messages, as we will shut down - don't want this function to repeat!
@@ -1173,7 +1209,7 @@ void ApplicationManagerBase::InitBuilderManager()
         {
             m_builderManager->ConnectionLost(connId);
         });
-    
+
 }
 
 void ApplicationManagerBase::ShutdownBuilderManager()
@@ -1207,7 +1243,7 @@ void ApplicationManagerBase::ShutDownAssetDatabase()
     AzToolsFramework::AssetDatabase::AssetDatabaseRequests::Bus::Handler::BusDisconnect();
 }
 
-void ApplicationManagerBase::InitFileProcessor() 
+void ApplicationManagerBase::InitFileProcessor()
 {
     AssetProcessor::ThreadController<AssetProcessor::FileProcessor>* fileProcessorHelper = new AssetProcessor::ThreadController<AssetProcessor::FileProcessor>();
 
@@ -1298,22 +1334,13 @@ bool ApplicationManagerBase::Activate()
     }
 
     InitBuilderConfiguration();
-
-    m_isCurrentlyLoadingGems = true;
-    if (!ActivateModules())
-    {
-        // ActivateModules reports any errors it encounters.
-        m_isCurrentlyLoadingGems = false;
-        return false;
-    }
-
-    m_isCurrentlyLoadingGems = false;
     PopulateApplicationDependencies();
 
     InitAssetProcessorManager();
     AssetBuilderSDK::InitializeSerializationContext();
     AssetBuilderSDK::InitializeBehaviorContext();
-    
+    AssetBuilder::InitializeSerializationContext();
+
     InitFileStateCache();
     InitFileProcessor();
 
@@ -1341,7 +1368,7 @@ bool ApplicationManagerBase::Activate()
     RegisterObjectForQuit(m_rcController);
 
     m_connectionsToRemoveOnShutdown << QObject::connect(
-        m_assetProcessorManager, &AssetProcessor::AssetProcessorManager::AssetProcessorManagerIdleState, 
+        m_assetProcessorManager, &AssetProcessor::AssetProcessorManager::AssetProcessorManagerIdleState,
         this, [this](bool state)
         {
             if (state)
@@ -1362,7 +1389,7 @@ bool ApplicationManagerBase::Activate()
         });
 
     m_connectionsToRemoveOnShutdown << QObject::connect(
-        this, &ApplicationManagerBase::CheckAssetProcessorManagerIdleState, 
+        this, &ApplicationManagerBase::CheckAssetProcessorManagerIdleState,
         m_assetProcessorManager, &AssetProcessor::AssetProcessorManager::CheckAssetProcessorIdleState);
 
     MakeActivationConnections();
@@ -1376,6 +1403,22 @@ bool ApplicationManagerBase::Activate()
             return false;
         }
     }
+
+    AssetProcessor::AssetProcessorStatusEntry entry(AssetProcessor::AssetProcessorStatus::Initializing_Builders, 0, QString());
+    Q_EMIT AssetProcessorStatusChanged(entry);
+
+    AZStd::thread_desc desc;
+    desc.m_name = "Builder Component Registration";
+    AZStd::thread builderRegistrationThread(
+        desc,
+        []()
+        {
+            AssetProcessor::BuilderRef builder;
+            AssetProcessor::BuilderManagerBus::BroadcastResult(builder, &AssetProcessor::BuilderManagerBus::Events::GetBuilder, true);
+        });
+
+    builderRegistrationThread.detach();
+
     return true;
 }
 
@@ -1384,11 +1427,6 @@ bool ApplicationManagerBase::PostActivate()
     m_connectionManager->LoadConnections();
 
     InitializeInternalBuilders();
-    if (!InitializeExternalBuilders())
-    {
-        AZ_Error("AssetProcessor", false, "AssetProcessor is closing. Failed to initialize and load all the external builders. Please ensure that Builders_Temp directory is not read-only. Please see log for more information.\n");
-        return false;
-    }
 
     Q_EMIT OnBuildersRegistered();
 
@@ -1401,7 +1439,7 @@ bool ApplicationManagerBase::PostActivate()
             AZ::SystemTickBus::Broadcast(&AZ::SystemTickEvents::OnSystemTick);
         });
 
-    // now that everything is up and running, we start scanning.  Before this, we don't want file events to start percolating through the 
+    // now that everything is up and running, we start scanning.  Before this, we don't want file events to start percolating through the
     // asset system.
 
     GetAssetScanner()->StartScan();
@@ -1425,124 +1463,20 @@ bool ApplicationManagerBase::InitializeInternalBuilders()
     return result;
 }
 
-bool ApplicationManagerBase::InitializeExternalBuilders()
-{
-    AssetProcessor::AssetProcessorStatusEntry entry(AssetProcessor::AssetProcessorStatus::Initializing_Builders);
-    Q_EMIT AssetProcessorStatusChanged(entry);
-    QCoreApplication::processEvents(QEventLoop::AllEvents);
-
-
-    // Get the list of external build modules (full paths)
-    QStringList fileList;
-    GetExternalBuilderFileList(fileList);
-
-    for (const QString& filePath : fileList)
-    {
-        if (QLibrary::isLibrary(filePath))
-        {
-            AssetProcessor::ExternalModuleAssetBuilderInfo* externalAssetBuilderInfo = new AssetProcessor::ExternalModuleAssetBuilderInfo(filePath);
-            AssetProcessor::AssetBuilderType assetBuilderType = externalAssetBuilderInfo->Load();
-            AZ_TracePrintf(AssetProcessor::ConsoleChannel, "AssetProcessor is loading library %s\n", filePath.toUtf8().data());
-            if (assetBuilderType == AssetProcessor::AssetBuilderType::None)
-            {
-                AZ_Warning(AssetProcessor::DebugChannel, false, "Non-builder DLL was found in Builders directory %s, skipping. \n", filePath.toUtf8().data());
-                delete externalAssetBuilderInfo;
-                continue;
-            }
-
-            if (assetBuilderType == AssetProcessor::AssetBuilderType::Invalid)
-            {
-                AZ_Warning(AssetProcessor::DebugChannel, false, "AssetProcessor was not able to load the library: %s\n", filePath.toUtf8().data());
-                delete externalAssetBuilderInfo;
-                return false;
-            }
-
-            AZ_TracePrintf(AssetProcessor::ConsoleChannel, "Initializing and registering builder %s\n", externalAssetBuilderInfo->GetName().toUtf8().data());
-
-            m_currentExternalAssetBuilder = externalAssetBuilderInfo;
-
-            externalAssetBuilderInfo->Initialize();
-
-            m_currentExternalAssetBuilder = nullptr;
-
-            m_externalAssetBuilders.push_back(externalAssetBuilderInfo);
-        }
-    }
-
-    // Also init external builders which may be inside of Gems
-    AzToolsFramework::ToolsApplicationRequestBus::Broadcast(
-        &AzToolsFramework::ToolsApplicationRequests::CreateAndAddEntityFromComponentTags,
-        AZStd::vector<AZ::Crc32>({ AssetBuilderSDK::ComponentTags::AssetBuilder }), "AssetBuilders Entity");
-
-    return true;
-}
-
-bool ApplicationManagerBase::WaitForBuilderExit(AzFramework::ProcessWatcher* processWatcher, AssetBuilderSDK::JobCancelListener* jobCancelListener, AZ::u32 processTimeoutLimitInSeconds)
-{
-    AZ::u32 exitCode = 0;
-    bool finishedOK = false;
-    QElapsedTimer ticker;
-    ProcessCommunicatorTracePrinter tracer(processWatcher->GetCommunicator(), "AssetBuilder");
-
-    ticker.start();
-
-    while (!finishedOK)
-    {
-        AZStd::this_thread::sleep_for(AZStd::chrono::milliseconds(s_MaximumSleepTimeMS));
-
-        tracer.Pump();
-
-        if (ticker.elapsed() > processTimeoutLimitInSeconds * 1000 || (jobCancelListener && jobCancelListener->IsCancelled()))
-        {
-            break;
-        }
-
-        if (!processWatcher->IsProcessRunning(&exitCode))
-        {
-            finishedOK = true; // we either cant wait for it, or it finished.
-            break;
-        }
-    }
-
-    tracer.Pump(); // empty whats left if possible.
-
-    if (processWatcher->IsProcessRunning(&exitCode))
-    {
-        processWatcher->TerminateProcess(1);
-    }
-
-    if (exitCode != 0)
-    {
-        AZ_Error(AssetProcessor::ConsoleChannel, false, "AssetBuilder exited with error code %d", exitCode);
-        return false;
-    }
-    else if (jobCancelListener && jobCancelListener->IsCancelled())
-    {
-        AZ_TracePrintf(AssetProcessor::DebugChannel, "AssetBuilder was terminated. There was a request to cancel the job.\n");
-        return false;
-    }
-    else if (!finishedOK)
-    {
-        AZ_Error(AssetProcessor::ConsoleChannel, false, "AssetBuilder failed to terminate within %d seconds", processTimeoutLimitInSeconds);
-        return false;
-    }
-
-    return true;
-}
-
 void ApplicationManagerBase::RegisterBuilderInformation(const AssetBuilderSDK::AssetBuilderDesc& builderDesc)
 {
-    // Create Job Function validation
-    AZ_Error(AssetProcessor::ConsoleChannel,
-        builderDesc.m_createJobFunction,
-        "Create Job Function (m_createJobFunction) for %s builder is empty.\n",
-        builderDesc.m_name.c_str());
+    if (!builderDesc.IsExternalBuilder())
+    {
+        // Create Job Function validation
+        AZ_Error(
+            AssetProcessor::ConsoleChannel, builderDesc.m_createJobFunction,
+            "Create Job Function (m_createJobFunction) for %s builder is empty.\n", builderDesc.m_name.c_str());
 
-    // Process Job Function validation
-    AZ_Error(AssetProcessor::ConsoleChannel,
-        builderDesc.m_processJobFunction,
-        "Process Job Function (m_processJobFunction) for %s builder is empty.\n",
-        builderDesc.m_name.c_str());
+        // Process Job Function validation
+        AZ_Error(
+            AssetProcessor::ConsoleChannel, builderDesc.m_processJobFunction,
+            "Process Job Function (m_processJobFunction) for %s builder is empty.\n", builderDesc.m_name.c_str());
+    }
 
     // Bus ID validation
     AZ_Error(AssetProcessor::ConsoleChannel,
@@ -1550,67 +1484,66 @@ void ApplicationManagerBase::RegisterBuilderInformation(const AssetBuilderSDK::A
         "Bus ID for %s builder is empty.\n",
         builderDesc.m_name.c_str());
 
-    // This is an external builder registering, we will want to track its builder desc since it can register multiple ones
-    AZStd::string builderFilePath;
-    if (m_currentExternalAssetBuilder)
-    {
-        m_currentExternalAssetBuilder->RegisterBuilderDesc(builderDesc.m_busId);
-        builderFilePath = m_currentExternalAssetBuilder->GetModuleFullPath().toUtf8().data();
-    }
-
     AssetBuilderSDK::AssetBuilderDesc modifiedBuilderDesc = builderDesc;
     // Allow for overrides defined in a BuilderConfig.ini file to update our code defined default values
     AssetProcessor::BuilderConfigurationRequestBus::Broadcast(&AssetProcessor::BuilderConfigurationRequests::UpdateBuilderDescriptor, builderDesc.m_name, modifiedBuilderDesc);
 
     if (builderDesc.IsExternalBuilder())
     {
-        // We're going to override the createJob function so we can run it externally in AssetBuilder, rather than having it run inside the AP
-        modifiedBuilderDesc.m_createJobFunction = [builderFilePath](const AssetBuilderSDK::CreateJobsRequest& request, AssetBuilderSDK::CreateJobsResponse& response)
+        // We're going to override the createJob function so we can run it externally in AssetBuilder, rather than having it run
+        // inside the AP
+        modifiedBuilderDesc.m_createJobFunction =
+            [](const AssetBuilderSDK::CreateJobsRequest& request, AssetBuilderSDK::CreateJobsResponse& response)
+        {
+            AssetProcessor::BuilderRef builderRef;
+            AssetProcessor::BuilderManagerBus::BroadcastResult(builderRef, &AssetProcessor::BuilderManagerBusTraits::GetBuilder, false);
+
+            if (builderRef)
             {
-                AssetProcessor::BuilderRef builderRef;
-                AssetProcessor::BuilderManagerBus::BroadcastResult(builderRef, &AssetProcessor::BuilderManagerBusTraits::GetBuilder);
+                int retryCount = 0;
+                AssetProcessor::BuilderRunJobOutcome result;
 
-                if (builderRef)
+                do
                 {
-                    int retryCount = 0;
-                    AssetProcessor::BuilderRunJobOutcome result;
-
-                    do
-                    {
-                        retryCount++;
-                        result = builderRef->RunJob<AssetBuilderSDK::CreateJobsNetRequest, AssetBuilderSDK::CreateJobsNetResponse>(request, response, s_MaximumCreateJobsTimeSeconds, "create", builderFilePath, nullptr);
-                    } while (result == AssetProcessor::BuilderRunJobOutcome::LostConnection && retryCount <= AssetProcessor::RetriesForJobNetworkError);
-                }
-                else
-                {
-                    AZ_Error("AssetProcessor", false, "Failed to retrieve a valid builder to process job");
-                }
-            };
+                    retryCount++;
+                    result = builderRef->RunJob<AssetBuilder::CreateJobsNetRequest, AssetBuilder::CreateJobsNetResponse>(
+                        request, response, s_MaximumCreateJobsTimeSeconds, "create", "", nullptr);
+                } while (result == AssetProcessor::BuilderRunJobOutcome::LostConnection &&
+                         retryCount <= AssetProcessor::RetriesForJobNetworkError);
+            }
+            else
+            {
+                AZ_Error("AssetProcessor", false, "Failed to retrieve a valid builder to process job");
+            }
+        };
 
         // Also override the processJob function to run externally
-        modifiedBuilderDesc.m_processJobFunction = [builderFilePath](const AssetBuilderSDK::ProcessJobRequest& request, AssetBuilderSDK::ProcessJobResponse& response)
+        modifiedBuilderDesc.m_processJobFunction =
+            [](const AssetBuilderSDK::ProcessJobRequest& request, AssetBuilderSDK::ProcessJobResponse& response)
+        {
+            AssetBuilderSDK::JobCancelListener jobCancelListener(request.m_jobId);
+
+            AssetProcessor::BuilderRef builderRef;
+            AssetProcessor::BuilderManagerBus::BroadcastResult(builderRef, &AssetProcessor::BuilderManagerBusTraits::GetBuilder, false);
+
+            if (builderRef)
             {
-                AssetBuilderSDK::JobCancelListener jobCancelListener(request.m_jobId);
+                int retryCount = 0;
+                AssetProcessor::BuilderRunJobOutcome result;
 
-                AssetProcessor::BuilderRef builderRef;
-                AssetProcessor::BuilderManagerBus::BroadcastResult(builderRef, &AssetProcessor::BuilderManagerBusTraits::GetBuilder);
-
-                if (builderRef)
+                do
                 {
-                    int retryCount = 0;
-                    AssetProcessor::BuilderRunJobOutcome result;
-
-                    do
-                    {
-                        retryCount++;
-                        result = builderRef->RunJob<AssetBuilderSDK::ProcessJobNetRequest, AssetBuilderSDK::ProcessJobNetResponse>(request, response, s_MaximumProcessJobsTimeSeconds, "process", builderFilePath, &jobCancelListener, request.m_tempDirPath);
-                    } while (result == AssetProcessor::BuilderRunJobOutcome::LostConnection && retryCount <= AssetProcessor::RetriesForJobNetworkError);
-                }
-                else
-                {
-                    AZ_Error("AssetProcessor", false, "Failed to retrieve a valid builder to process job");
-                }
-            };
+                    retryCount++;
+                    result = builderRef->RunJob<AssetBuilder::ProcessJobNetRequest, AssetBuilder::ProcessJobNetResponse>(
+                        request, response, s_MaximumProcessJobsTimeSeconds, "process", "", &jobCancelListener, request.m_tempDirPath);
+                } while (result == AssetProcessor::BuilderRunJobOutcome::LostConnection &&
+                         retryCount <= AssetProcessor::RetriesForJobNetworkError);
+            }
+            else
+            {
+                AZ_Error("AssetProcessor", false, "Failed to retrieve a valid builder to process job");
+            }
+        };
     }
 
     if (m_builderDescMap.find(modifiedBuilderDesc.m_busId) != m_builderDescMap.end())
@@ -1768,7 +1701,7 @@ bool ApplicationManagerBase::CheckSufficientDiskSpace(const QString& savePath, q
     [[maybe_unused]] bool result = AzToolsFramework::ToolsFileUtils::GetFreeDiskSpace(savePath, bytesFree);
 
     AZ_Assert(result, "Unable to determine the amount of free space on drive containing path (%s).", savePath.toUtf8().constData());
-    
+
     if (bytesFree < requiredSpace + s_ReservedDiskSpaceInBytes)
     {
         if (shutdownIfInsufficient)
@@ -1806,8 +1739,8 @@ void ApplicationManagerBase::RemoveOldTempFolders()
         return;
     }
 
-    // We will remove old temp folders if either their modified time is older than the cutoff time or 
-    // if the total number of temp folders have exceeded the maximum number of temp folders.   
+    // We will remove old temp folders if either their modified time is older than the cutoff time or
+    // if the total number of temp folders have exceeded the maximum number of temp folders.
     QFileInfoList entries = root.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot, QDir::Time); // sorting by modification time
     int folderCount = 0;
     bool removeFolder = false;
@@ -1821,9 +1754,9 @@ void ApplicationManagerBase::RemoveOldTempFolders()
 
         // Since we are sorting the folders list from latest to oldest, we will either be in a state where we have to delete all the remaining folders or not
         // because either we have reached the folder limit or reached the cutoff date limit.
-        removeFolder = removeFolder || (folderCount++ >= s_MaximumTempFolders) || 
+        removeFolder = removeFolder || (folderCount++ >= s_MaximumTempFolders) ||
             (entry.lastModified() < cutoffTime);
-        
+
         if (removeFolder)
         {
             QDir dir(entry.absoluteFilePath());
@@ -1837,8 +1770,6 @@ void ApplicationManagerBase::ConnectivityStateChanged(const AzToolsFramework::So
     Q_EMIT SourceControlReady();
 }
 
-
-
 void ApplicationManagerBase::OnAssetProcessorManagerIdleState(bool isIdle)
 {
     // these can come in during shutdown.

Code/Tools/AssetProcessor/native/utilities/ApplicationManagerBase.h

@@ -149,7 +149,6 @@ protected:
     void CreateQtApplication() override;
 
     bool InitializeInternalBuilders();
-    bool InitializeExternalBuilders();
     void InitBuilderManager();
     void ShutdownBuilderManager();
     bool InitAssetDatabase();
@@ -173,8 +172,6 @@ protected:
 
     AssetProcessor::AssetCatalog* GetAssetCatalog() const { return m_assetCatalog; }
 
-    static bool WaitForBuilderExit(AzFramework::ProcessWatcher* processWatcher, AssetBuilderSDK::JobCancelListener* jobCancelListener, AZ::u32 processTimeoutLimitInSeconds);
-
     ApplicationServer* m_applicationServer = nullptr;
     ConnectionManager* m_connectionManager = nullptr;
 
@@ -218,6 +215,8 @@ protected:
     AZStd::shared_ptr<AssetProcessor::InternalRecognizerBasedBuilder> m_internalBuilder;
     AZStd::shared_ptr<AssetProcessor::SettingsRegistryBuilder> m_settingsRegistryBuilder;
 
+    bool m_builderRegistrationComplete = false;
+
     // Builder description map based on the builder id
     AZStd::unordered_map<AZ::Uuid, AssetBuilderSDK::AssetBuilderDesc> m_builderDescMap;
 
@@ -231,7 +230,7 @@ protected:
     AZStd::list<AssetProcessor::ExternalModuleAssetBuilderInfo*>    m_externalAssetBuilders;
 
     AssetProcessor::ExternalModuleAssetBuilderInfo* m_currentExternalAssetBuilder = nullptr;
-    
+
     QAtomicInt m_connectionsAwaitingAssetCatalogSave = 0;
     int m_remainingAPMJobs = 0;
     bool m_assetProcessorManagerIsReady = false;

Code/Tools/AssetProcessor/native/utilities/BuilderManager.cpp

@@ -16,6 +16,7 @@
 #include <native/utilities/AssetBuilderInfo.h>
 #include <QCoreApplication>
 #include <AzCore/Settings/SettingsRegistryMergeUtils.h>
+#include <AssetBuilder/AssetBuilderStatic.h>
 
 namespace AssetProcessor
 {
@@ -138,7 +139,7 @@ namespace AssetProcessor
         }
     }
 
-    bool Builder::Start()
+    bool Builder::Start(bool doRegistration)
     {
         // Get the current BinXXX folder based on the current running AP
         QString applicationDir = QCoreApplication::instance()->applicationDirPath();
@@ -155,7 +156,7 @@ namespace AssetProcessor
             return false;
         }
 
-        const AZStd::vector<AZStd::string> params = BuildParams("resident", buildersFolder.c_str(), UuidString(), "", "");
+        const AZStd::vector<AZStd::string> params = BuildParams("resident", buildersFolder.c_str(), UuidString(), "", "", doRegistration);
 
         m_processWatcher = LaunchProcess(fullExePathString.c_str(), params);
 
@@ -179,7 +180,7 @@ namespace AssetProcessor
         return !m_processWatcher || (m_processWatcher && m_processWatcher->IsProcessRunning(exitCode));
     }
 
-    AZStd::vector<AZStd::string> Builder::BuildParams(const char* task, const char* moduleFilePath, const AZStd::string& builderGuid, const AZStd::string& jobDescriptionFile, const AZStd::string& jobResponseFile) const
+    AZStd::vector<AZStd::string> Builder::BuildParams(const char* task, const char* moduleFilePath, const AZStd::string& builderGuid, const AZStd::string& jobDescriptionFile, const AZStd::string& jobResponseFile, bool doRegistration) const
     {
         QDir projectCacheRoot;
         AssetUtilities::ComputeProjectCacheRoot(projectCacheRoot);
@@ -200,6 +201,11 @@ namespace AssetProcessor
         params.emplace_back(AZStd::string::format(R"(-engine-path="%s")", enginePath.c_str()));
         params.emplace_back(AZStd::string::format("-port=%d", portNumber));
 
+        if(doRegistration)
+        {
+            params.emplace_back("--register");
+        }
+
         if (moduleFilePath && moduleFilePath[0])
         {
             params.emplace_back(AZStd::string::format(R"(-module="%s")", moduleFilePath));
@@ -232,7 +238,7 @@ namespace AssetProcessor
     {
         AzFramework::ProcessLauncher::ProcessLaunchInfo processLaunchInfo;
         processLaunchInfo.m_processExecutableString = fullExePath;
-        
+
         AZStd::vector<AZStd::string> commandLineArray{ fullExePath };
         commandLineArray.insert(commandLineArray.end(), params.begin(), params.end());
         processLaunchInfo.m_commandlineParameters = AZStd::move(commandLineArray);
@@ -350,17 +356,19 @@ namespace AssetProcessor
     BuilderManager::BuilderManager(ConnectionManager* connectionManager)
     {
         using namespace AZStd::placeholders;
-        connectionManager->RegisterService(AssetBuilderSDK::BuilderHelloRequest::MessageType(), AZStd::bind(&BuilderManager::IncomingBuilderPing, this, _1, _2, _3, _4, _5));
+        connectionManager->RegisterService(AssetBuilder::BuilderHelloRequest::MessageType(), AZStd::bind(&BuilderManager::IncomingBuilderPing, this, _1, _2, _3, _4, _5));
 
         // Setup a background thread to pump the idle builders so they don't get blocked trying to output to stdout/err
-        m_pollingThread = AZStd::thread([this]()
+        AZStd::thread_desc desc;
+        desc.m_name = "BuilderManager Idle Pump";
+        m_pollingThread = AZStd::thread(desc, [this]()
+            {
+                while (!m_quitListener.WasQuitRequested())
                 {
-                    while (!m_quitListener.WasQuitRequested())
-                    {
-                        PumpIdleBuilders();
-                        AZStd::this_thread::sleep_for(AZStd::chrono::milliseconds(s_IdleBuilderPumpingDelayMS));
-                    }
-                });
+                    PumpIdleBuilders();
+                    AZStd::this_thread::sleep_for(AZStd::chrono::milliseconds(s_IdleBuilderPumpingDelayMS));
+                }
+            });
 
         m_quitListener.BusConnect();
         BusConnect();
@@ -399,8 +407,8 @@ namespace AssetProcessor
 
     void BuilderManager::IncomingBuilderPing(AZ::u32 connId, AZ::u32 /*type*/, AZ::u32 serial, QByteArray payload, QString platform)
     {
-        AssetBuilderSDK::BuilderHelloRequest requestPing;
-        AssetBuilderSDK::BuilderHelloResponse responsePing;
+        AssetBuilder::BuilderHelloRequest requestPing;
+        AssetBuilder::BuilderHelloResponse responsePing;
 
         if (!AZ::Utils::LoadObjectFromBufferInPlace(payload.data(), payload.length(), requestPing))
         {
@@ -476,7 +484,7 @@ namespace AssetProcessor
         return builder;
     }
 
-    BuilderRef BuilderManager::GetBuilder()
+    BuilderRef BuilderManager::GetBuilder(bool doRegistration)
     {
         AZStd::shared_ptr<Builder> newBuilder;
         BuilderRef builderRef;
@@ -484,27 +492,30 @@ namespace AssetProcessor
         {
             AZStd::unique_lock<AZStd::mutex> lock(m_buildersMutex);
 
-            for (auto itr = m_builders.begin(); itr != m_builders.end(); )
+            if (!doRegistration)
             {
-                auto& builder = itr->second;
-
-                if (!builder->m_busy)
+                for (auto itr = m_builders.begin(); itr != m_builders.end();)
                 {
-                    builder->PumpCommunicator();
+                    auto& builder = itr->second;
 
-                    if (builder->IsValid())
+                    if (!builder->m_busy)
                     {
-                        return BuilderRef(builder);
+                        builder->PumpCommunicator();
+
+                        if (builder->IsValid())
+                        {
+                            return BuilderRef(builder);
+                        }
+                        else
+                        {
+                            itr = m_builders.erase(itr);
+                        }
                     }
                     else
                     {
-                        itr = m_builders.erase(itr);
+                        ++itr;
                     }
                 }
-                else
-                {
-                    ++itr;
-                }
             }
 
             AZ_TracePrintf("BuilderManager", "Starting new builder for job request\n");
@@ -516,7 +527,7 @@ namespace AssetProcessor
             builderRef = BuilderRef(newBuilder);
         }
 
-        if (!newBuilder->Start())
+        if (!newBuilder->Start(doRegistration))
         {
             AZ_Error("BuilderManager", false, "Builder failed to start");
 

Code/Tools/AssetProcessor/native/utilities/BuilderManager.h

@@ -39,7 +39,7 @@ namespace AssetProcessor
         virtual ~BuilderManagerBusTraits() = default;
 
         //! Returns a builder for doing work
-        virtual BuilderRef GetBuilder() = 0;
+        virtual BuilderRef GetBuilder(bool doRegistration) = 0;
     };
 
     using BuilderManagerBus = AZ::EBus<BuilderManagerBusTraits>;
@@ -98,12 +98,12 @@ namespace AssetProcessor
     private:
 
         //! Starts the builder process and waits for it to connect
-        bool Start();
+        bool Start(bool doRegistration);
 
         //! Sets the connection id and signals that the builder has connected
         void SetConnection(AZ::u32 connId);
 
-        AZStd::vector<AZStd::string> BuildParams(const char* task, const char* moduleFilePath, const AZStd::string& builderGuid, const AZStd::string& jobDescriptionFile, const AZStd::string& jobResponseFile) const;
+        AZStd::vector<AZStd::string> BuildParams(const char* task, const char* moduleFilePath, const AZStd::string& builderGuid, const AZStd::string& jobDescriptionFile, const AZStd::string& jobResponseFile, bool doRegistration) const;
         AZStd::unique_ptr<AzFramework::ProcessWatcher> LaunchProcess(const char* fullExePath, const AZStd::vector<AZStd::string>& params) const;
 
         //! Waits for the builder exe to send the job response and pumps stdout/err
@@ -169,7 +169,7 @@ namespace AssetProcessor
         void ConnectionLost(AZ::u32 connId);
 
         //BuilderManagerBus
-        BuilderRef GetBuilder() override;
+        BuilderRef GetBuilder(bool doRegistration) override;
 
     private:
 

Code/Tools/AssetProcessor/native/utilities/BuilderManager.inl

@@ -50,7 +50,7 @@ namespace AssetProcessor
 
         if (!netResponse.m_response.Succeeded() || s_createRequestFileForSuccessfulJob)
         {
-            // we write the request out to disk for failure or debugging 
+            // we write the request out to disk for failure or debugging
             if (!DebugWriteRequestFile(tempFolderPath.c_str(), request, task, modulePath))
             {
                 return BuilderRunJobOutcome::FailedToWriteDebugRequest;
@@ -83,7 +83,7 @@ namespace AssetProcessor
             return false;
         }
 
-        auto params = BuildParams(task.c_str(), modulePath.c_str(), "", jobRequestFile, jobResponseFile);
+        auto params = BuildParams(task.c_str(), modulePath.c_str(), "", jobRequestFile, jobResponseFile, false);
         AZStd::string paramString;
         AZ::StringFunc::Join(paramString, params.begin(), params.end(), " ");
 

Code/Tools/AssetProcessor/native/utilities/GUIApplicationManager.cpp

@@ -318,16 +318,8 @@ bool GUIApplicationManager::Run()
 
     qApp->setQuitOnLastWindowClosed(false);
 
-    QTimer::singleShot(0, this, [this]()
-    {
-        if (!PostActivate())
-        {
-            QuitRequested();
-            m_startedSuccessfully = false;
-        }
-    });
-
     m_duringStartup = false;
+    m_startedSuccessfully = true;
 
     int resultCode =  qApp->exec(); // this blocks until the last window is closed.
 
@@ -483,6 +475,7 @@ bool GUIApplicationManager::PostActivate()
 {
     if (!ApplicationManagerBase::PostActivate())
     {
+        m_startedSuccessfully = false;
         return false;
     }