Merge all outstanding changesets

Commit messages as follows:

Change-Id: I631d374144efc540b158868fa65a0bac232a7548
---
Changed the comments for the SLO Violation handler
---
Performance update:
Adding a boolean flag to indicate when all metrics have been set to avoid a linear scan of all metrics on each SLO Violation message.
---
Metric list and reconfiguration wait
Metric updater now listening for a metric list from the Optimiser Controller and not frmo the EMS, and discards SLO Violations until the Optimiser Controller sends a message indicating that the previous application reconfiguration has finished.
---
Log message to indicate that the "reconfiguration done" even message has been received
---
Added the right topic for the metric list
---
New messages
Metric list from the controller
New message format for AMPL model definition
Fixed the AMQ message property settings

.gitignore

@@ -3,3 +3,5 @@ __pycache__/
 *.d
 /SolverComponent
 /ampl.lic
+*.~1NiBF4kGEKO5WetCRbF0UOTl6FtAH2hiz-f9e028.insyncdl
+*.insyncdl

.vscode/c_cpp_properties.json

@@ -7,8 +7,12 @@
                 "/home/GHo/Documents/Code/CxxOpts/include",
                 "/opt/AMPL/amplapi/include/",
                 "${workspaceFolder}/**",
-                "/usr/lib/gcc/x86_64-redhat-linux/13/../../../../include/c++/13",
+                "/home/GHo/Documents/Code/NebulOuS/Solvers",
-                "/home/GHo/Documents/Code/Theron++"
+                "/usr/include/c++/13",
+                "/home/GHo/Documents/Code/Theron++",
+                "/usr/include/c++/13/x86_64-redhat-linux",
+                "/usr/include/linux",
+                "/usr/include/c++/13/tr1"
             ],
             "defines": [],
             "cStandard": "c23",
@@ -29,7 +33,9 @@
                     "/home/GHo/Documents/Code/Theron++/",
                     "/home/GHo/Documents/Code/CxxOpts/include",
                     "/opt/AMPL/amplapi/include/",
-                    "/usr/lib/gcc/x86_64-redhat-linux/13/../../../../include/c++/13"
+                    "/usr/include/c++/13",
+                    "/usr/include/linux",
+                    "/home/GHo/Documents/Code/NebulOuS/Solvers"
                 ],
                 "limitSymbolsToIncludedHeaders": false
             }

AMPLSolver.cpp

@@ -31,50 +31,30 @@ namespace NebulOuS
 // is received updating AMPL model parameters. Hence the common file creation
 // is taken care of by a dedicated function.
 
-std::string AMPLSolver::SaveFile( const JSON & TheMessage, 
+std::string AMPLSolver::SaveFile( std::string_view TheName, 
+                                  std::string_view TheContent,
                                   const std::source_location & Location )
 {
-  if( TheMessage.is_object() )
+  std::string TheFileName = ProblemFileDirectory / TheName;
+
+  std::fstream TheFile( TheFileName, std::ios::out | std::ios::binary );
+                      
+  if( TheFile.is_open() )
   {
-    std::string TheFileName 
+    TheFile << TheContent;
-                = ProblemFileDirectory / TheMessage.at( AMPLSolver::FileName );
+    TheFile.close();
-
+    return TheFileName;
-    std::fstream ProblemFile( TheFileName, std::ios::out | std::ios::binary );
-                        
-    if( ProblemFile.is_open() )
-    {
-      ProblemFile << TheMessage.at( AMPLSolver::FileContent ).get<std::string>();
-      ProblemFile.close();
-      return TheFileName;
-    }
-    else
-    {
-      std::source_location Location = std::source_location::current();
-      std::ostringstream ErrorMessage;
-
-      ErrorMessage << "[" << Location.file_name() << " at line " 
-                  << Location.line()
-                  << "in function " << Location.function_name() <<"] " 
-                  << "The AMPL file at "
-                  << TheFileName
-                  << " could not be opened for output!";
-
-      throw std::system_error( static_cast< int >( std::errc::io_error ),
-                               std::system_category(), ErrorMessage.str() );
-    }
   }
   else
   {
-    std::source_location Location = std::source_location::current();
     std::ostringstream ErrorMessage;
 
     ErrorMessage << "[" << Location.file_name() << " at line " 
                 << Location.line()
                 << "in function " << Location.function_name() <<"] " 
-                << "The JSON message is not an object. The received "
+                << "The AMPL file at "
-                << "message is " << std::endl
+                << TheFileName
-                << TheMessage.dump(2)
+                << " could not be opened for output!";
-                << std::endl;
 
     throw std::system_error( static_cast< int >( std::errc::io_error ),
                               std::system_category(), ErrorMessage.str() );
@@ -163,13 +143,18 @@ void AMPLSolver::DefineProblem(const Solver::OptimisationProblem & TheProblem,
   // First storing the AMPL problem file from its definition in the message
   // and read the file back to the AMPL interpreter.
 
-  ProblemDefinition.read( SaveFile( TheProblem ) );
+  ProblemDefinition.read( SaveFile( 
+    TheProblem.at( 
+      OptimisationProblem::Keys::ProblemFile ).get< std::string >() ,
+    TheProblem.at( 
+      OptimisationProblem::Keys::ProblemDescription ).get< std::string >() ) );
 
   // The next is to read the label of the default objective function and 
   // store this. An invalid argument exception is thrown if the field is missing
 
-  if( TheProblem.contains( Solver::ObjectiveFunctionLabel ) )
+  if( TheProblem.contains(OptimisationProblem::Keys::DefaultObjectiveFunction) )
-    DefaultObjectiveFunction = TheProblem.at( Solver::ObjectiveFunctionLabel );
+    DefaultObjectiveFunction 
+      = TheProblem.at( OptimisationProblem::Keys::DefaultObjectiveFunction );
   else
   {
     std::source_location Location = std::source_location::current();
@@ -180,24 +165,44 @@ void AMPLSolver::DefineProblem(const Solver::OptimisationProblem & TheProblem,
                   << "in function " << Location.function_name() <<"] " 
                   << "The problem definition must contain a default objective "
                   << "function under the key [" 
-                  << Solver::ObjectiveFunctionLabel
+                  << OptimisationProblem::Keys::DefaultObjectiveFunction
                   << "]" << std::endl;
 
     throw std::invalid_argument( ErrorMessage.str() );
   }
 
-  // After all the manatory fields have been processed, the set of constants 
+  // The default values for the data will be loaded from the data file. This
-  // will be processed storing the mapping from variable value to constant.
+  // operation is the same as the one done for data messages, and to avoid 
+  // code duplication the handler is just invoked using the address of this
+  // solver Actor as the the sender is not important for this update.
 
-  if( TheProblem.contains( ConstantsLabel ) &&
+  if( TheProblem.contains( DataFileMessage::Keys::DataFile ) && 
-      TheProblem.at( ConstantsLabel ).is_object() )
+      TheProblem.contains( DataFileMessage::Keys::NewData  )      )
+  {
+    std::string FileContent 
+        = TheProblem.at( DataFileMessage::Keys::NewData ).get< std::string >();
+
+    if( !FileContent.empty() )
+        DataFileUpdate( DataFileMessage(
+          TheProblem.at( DataFileMessage::Keys::DataFile ).get< std::string >(),
+          FileContent ), 
+          GetAddress() );
+  }
+
+  // The set of constants will be processed storing the mapping from a variable
+  // value to a constant.
+
+  if( TheProblem.contains( OptimisationProblem::Keys::Constants ) &&
+      TheProblem.at( OptimisationProblem::Keys::Constants ).is_object() )
     for( const auto & [ ConstantName, ConstantRecord ] :
-                      TheProblem.at( ConstantsLabel ).items() )
+         TheProblem.at( OptimisationProblem::Keys::Constants ).items() )
     {
-      VariablesToConstants.emplace( ConstantRecord.at( VariableName ), 
+      VariablesToConstants.emplace( 
-                                    ConstantName );
+        ConstantRecord.at( OptimisationProblem::Keys::VariableName ), 
+        ConstantName );
+
       SetAMPLParameter( ConstantName, 
-                        ConstantRecord.at( InitialConstantValue ) );
+        ConstantRecord.at( OptimisationProblem::Keys::InitialConstantValue ) );
     }
 
   // Finally, the problem has been defined and the flag is set to allow 
@@ -215,10 +220,12 @@ void AMPLSolver::DefineProblem(const Solver::OptimisationProblem & TheProblem,
 // the Define Problem message handler: The save file is used to store the 
 // received file, which is then loaded as the data problem.
 
-void AMPLSolver::DataFileUpdate( const DataFileMessage & TheDataFile, 
+void AMPLSolver::DataFileUpdate( const DataFileMessage & NewData, 
                                  const Address TheOracle )
 {
-  ProblemDefinition.readData( SaveFile( TheDataFile ) );
+  ProblemDefinition.readData( SaveFile( 
+    NewData.at( DataFileMessage::Keys::DataFile ).get< std::string >(),
+    NewData.at( DataFileMessage::Keys::NewData  ).get< std::string >() ) );
 }
 
 // -----------------------------------------------------------------------------
@@ -385,7 +392,7 @@ AMPLSolver::AMPLSolver( const std::string & TheActorName,
 
   Send( Theron::AMQ::NetworkLayer::TopicSubscription(
     Theron::AMQ::NetworkLayer::TopicSubscription::Action::Subscription,
-    Theron::AMQ::TopicName( DataFileMessage::MessageIdentifier )
+    DataFileMessage::AMQTopic
   ), GetSessionLayerAddress() );
 }
 
@@ -397,7 +404,7 @@ AMPLSolver::~AMPLSolver()
   if( HasNetwork() )
     Send( Theron::AMQ::NetworkLayer::TopicSubscription(
       Theron::AMQ::NetworkLayer::TopicSubscription::Action::CloseSubscription,
-      Theron::AMQ::TopicName( DataFileMessage::MessageIdentifier )
+      DataFileMessage::AMQTopic
     ), GetSessionLayerAddress() );
 }
 

AMPLSolver.hpp

@@ -85,21 +85,18 @@ class AMPLSolver
   // Utility methods
   // --------------------------------------------------------------------------
   //
-  // Since both the optimisation problem file and the data file(s) will be sent
+  // Since both the optimisation problem file and the data file(s) will arrive
-  // as JSON messages with a single key-value pair where the key is the filename
+  // as messages containing the file name and the then the content of the file
-  // and the value is the file content, there is a common dfinition of the 
+  // as a long text string. The following file will open the file for writing
-  // problem file directory and a function to read the file. The function will 
+  // and save the content string to this file.
-  // throw errors if the JSON message given is not an object, or of there are 
-  // issues opening the file name given. If the file could be successfully 
-  // saved, the functino will close the file and return the file name for 
-  // further processing.
 
 private:
 
   const std::filesystem::path ProblemFileDirectory;
 
-  std::string SaveFile( const JSON & TheMessage, 
+  std::string SaveFile( std::string_view TheName, 
-              const std::source_location  & Location 
+                        std::string_view TheContent, 
+                        const std::source_location  & Location 
                                           = std::source_location::current() );
 
   // There is also a utility function to look up a named AMPL parameter and 
@@ -130,28 +127,36 @@ protected:
   virtual void DefineProblem( const Solver::OptimisationProblem & TheProblem, 
                               const Address TheOracle ) override;
 
-  // The topic on which the problem file is posted is currently defined as a 
-  // constant string
-
-  static constexpr std::string_view AMPLProblemTopic 
-                   = "eu.nebulouscloud.optimiser.solver.model";
-
   // The JSON message received on this topic is supposed to contain several 
   // keys in the JSON message
   // 1) The filename of the problem file
   // 2) The file content as a single string
-  // 3) The default objective function (defined in the Solver class)
+  // 3) The name of the initial data file
-  // 4) An optional constants section containing constant names as keys
+  // 4) The content of the initial data file as a single string
+  // 5) The default objective function (defined in the Solver class)
+  // 6) An optional constants section containing constant names as keys
   //    and the values will be another map containing the variable 
   //    whose value should be passed to the constant, and the initial 
   //    value of the constant. 
+  // Since these elements are parts of the optimisation problem message
+  // whose class cannot be extended to contain these directly, it is 
+  // necessary to scope these keys differently for the compiler.
 
-  static constexpr std::string_view 
+  struct OptimisationProblem
-         FileName             = "FileName",
+  {
-         FileContent          = "FileContent",
+    struct Keys
-         ConstantsLabel       = "Constants",
+    {
-         VariableName         = "Variable",
+      static constexpr std::string_view
-         InitialConstantValue = "Value";
+        ProblemFile              = "ModelFileName",
+        ProblemDescription       = "ModelFileContent",
+        DataFile                 = "DataFileName",
+        InitialisationData       = "DataFileContent",
+        DefaultObjectiveFunction = "ObjectiveFunction",
+        Constants                = "Constants",
+        VariableName             = "Variable",
+        InitialConstantValue     = "Value";
+    };
+  }; 
 
   // Finally, no solution will be produced unless the problem has been 
   // defined. A flag is therefore set by the message handler indicating 
@@ -193,18 +198,27 @@ public:
   {
   public:
 
-    // The data files are assumed to be published on a dedicated topic for the 
+    // The data files are assumed to be published by the performance module 
-    // optimiser
+    // on a dedicated topic topic for the running solvers.
 
-    static constexpr std::string_view MessageIdentifier 
+    static constexpr std::string_view AMQTopic 
-                   = "eu.nebulouscloud.optimiser.solver.data";
+                   = "eu.nebulouscloud.optimiser.performancemodule.data";
 
+    // The received message will be a mapp supporting the following keys 
+    // basically defining the data file name and its content.
 
-    DataFileMessage( const std::string & TheDataFileName, 
+    struct Keys
+    {
+      static constexpr std::string_view
+        DataFile  = "DataFileName",
+        NewData   = "DataFileContent";
+    };
+
+    DataFileMessage( const std::string_view & TheDataFileName, 
                      const JSON & DataFileContent )
-    : JSONTopicMessage( std::string( MessageIdentifier ), 
+    : JSONTopicMessage( AMQTopic, 
-      { { FileName, TheDataFileName }, 
+      { { Keys::DataFile, TheDataFileName }, 
-        { FileContent, DataFileContent } } )
+        { Keys::NewData, DataFileContent } } )
     {}
 
     DataFileMessage( const DataFileMessage & Other )
@@ -212,7 +226,7 @@ public:
     {}
 
     DataFileMessage()
-    : JSONTopicMessage( std::string( MessageIdentifier ) )
+    : JSONTopicMessage( AMQTopic )
     {}
 
     virtual ~DataFileMessage() = default;

ExecutionControl.cpp

@@ -58,7 +58,7 @@ void ExecutionControl::StopMessageHandler( const StopMessage & Command,
   std::lock_guard< std::mutex > Lock( TerminationLock );
 
   Send( StatusMessage( StatusMessage::State::Stopped ), 
-                       Address( std::string( StatusTopic ) ) );
+                       Address( StatusMessage::AMQTopic ) );
 
   Send( Theron::Network::ShutDown(), 
         Theron::Network::GetAddress( Theron::Network::Layer::Session ) );
@@ -83,11 +83,11 @@ ExecutionControl::ExecutionControl( const std::string & TheActorName )
 
   Send( Theron::AMQ::NetworkLayer::TopicSubscription(
     Theron::AMQ::NetworkLayer::TopicSubscription::Action::Publisher,
-    std::string( StatusTopic )
+    StatusMessage::AMQTopic
   ), GetSessionLayerAddress() );
 
   Send( StatusMessage( StatusMessage::State::Starting ), 
-        Address( std::string( StatusTopic ) ) );
+        Address( StatusMessage::AMQTopic ) );
 
 }
 
@@ -99,7 +99,7 @@ ExecutionControl::~ExecutionControl( void )
   if( HasNetwork() )
     Send( Theron::AMQ::NetworkLayer::TopicSubscription(
       Theron::AMQ::NetworkLayer::TopicSubscription::Action::ClosePublisher,
-      std::string( StatusTopic )
+      StatusMessage::AMQTopic
     ), GetSessionLayerAddress() );
 }
 

ExecutionControl.hpp

@@ -110,19 +110,20 @@ protected:
 
   public:
 
+    // The status of the solver is communicated on the dedicated status topic
+
+    static constexpr std::string_view AMQTopic 
+                                      = "eu.nebulouscloud.solver.state";
+
+
     StatusMessage( State TheSituation, 
                    std::string AdditionalInformation = std::string() )
-    : JSONMessage( std::string( StatusTopic ),
+    : JSONMessage(  StatusMessage::AMQTopic,
                    { {"when", UTCNow() }, {"state", ToString( TheSituation ) },
                      {"message", AdditionalInformation } } )
     {}
   };
 
-  // The status of the solver is communicated on the dedicated status topic
-
-  static constexpr std::string_view StatusTopic 
-                                     = "eu.nebulouscloud.solver.state";
-
 public:
 
   // The function used to wait for the termination message simply waits on the

MetricUpdater.cpp

@@ -30,67 +30,66 @@ namespace NebulOuS
 // Subscribing to metric prediction values
 // --------------------------------------------------------------------------
 //
-// The received message must be a JSON object with metric names as 
+// The Optimiser controller defines the metric names used in the optimisatoin 
-// attribute (keys) and the topic name as the value. Multiple metrics maby be
+// model, and the metric subscription will subscribe to these. It is allowed 
-// included in the same message and and the andler will iterate and set up a 
+// that the metric list may change during run-time, and therefore the message
-// subcription for each of the provided metrics. It should be noted that 
+// hadler will make subscriptions for new metrics and remove subscriptions for
-// initially the metric has no value, and it is a prerequisite that all 
+// metrics that are not included in the list, but currently having 
-// metric values must be updated before the complete set of metrics will be 
+// subscriptions. 
-// used for finding a better configuration for the application's execution 
-// context given by the metric values.
-//
-// The message is just considered if the version number of the message is larger
-// than the version of the current set of metrics. The complicating factor is 
-// to deal with metrics that have changed in the case the metric version is 
-// increased. Then new metrics must be subscribed, deleted metrics must be 
-// unsubscribed, and values for kept metrics must be kept.
 
-void MetricUpdater::AddMetricSubscription( const MetricTopic & TheMetrics,
+void MetricUpdater::AddMetricSubscription( 
-                                           const Address OptimiserController )
+     const MetricTopic & MetricDefinitions, const Address OptimiserController )
 {
-  if( TheMetrics.is_object() && 
+  JSON TheMetrics = MetricDefinitions.at( MetricList );
-      TheMetrics.at( NebulOuS::MetricList ).is_array() )
+
+  if( TheMetrics.is_array() )
   {
-    if( MetricsVersion < TheMetrics.at( MetricVersionCounter ).get<long int>() )
+    // The first step is to try inserting the metrics into the metric value 
+    // map and if this is successful, a subscription is created for the 
+    // publisherof this metric value. The metric names are recorded since 
+    // some of them may correspond to known metrics, some of them may 
+    // correspond to metrics that are new.
+
+    std::set< std::string > TheMetricNames;
+
+    for (auto & MetricRecord : TheMetrics )
     {
-      // The first step is to try inserting the metrics into the metric value 
+      auto [ MetricRecordPointer, MetricAdded ] = MetricValues.try_emplace( 
-      // map and if this is successful, a subscription is created for the 
+             MetricRecord.get<std::string>(), JSON() );
-      // publisherof this metric value. The metric names are recorded since 
-      // some of them may correspond to known metrics, some of them may 
-      // correspond to metrics that are new.
 
-      std::set< std::string > TheMetricNames;
+      TheMetricNames.insert( MetricRecordPointer->first );
 
-      for (auto & MetricRecord : TheMetrics.at( NebulOuS::MetricList ) )
+      // If a new metric was added, a subscription will be set up for this 
+      // new metric, and the flag indicating that values have been received 
+      // for all metrics will be reset since this new metric has yet to receive
+      // its first value
+
+      if( MetricAdded )
       {
-        auto [ MetricRecordPointer, MetricAdded ] = MetricValues.try_emplace( 
+        Send( Theron::AMQ::NetworkLayer::TopicSubscription( 
-              MetricRecord.at( NebulOuS::MetricName ).get<std::string>(), JSON() );
+          Theron::AMQ::NetworkLayer::TopicSubscription::Action::Subscription,
+          std::string( MetricValueRootString ) + MetricRecordPointer->first ), 
+          GetSessionLayerAddress() );
 
-        TheMetricNames.insert( MetricRecordPointer->first );
+        AllMetricValuesSet = false;
-
-        if( MetricAdded )
-          Send( Theron::AMQ::NetworkLayer::TopicSubscription( 
-            Theron::AMQ::NetworkLayer::TopicSubscription::Action::Subscription,
-            std::string( MetricValueRootString ) + MetricRecordPointer->first ), 
-            GetSessionLayerAddress() );
       }
-
-      // There could be some metric value records that were defined by the
-      // previous metrics defined, but missing from the new metric set. If 
-      // this is the case, the metric value records for the missing metrics
-      // should be unsubcribed  and their metric records removed.
-
-      for( const auto & TheMetric : std::views::keys( MetricValues ) )
-        if( !TheMetricNames.contains( TheMetric ) )
-        {
-          Send( Theron::AMQ::NetworkLayer::TopicSubscription( 
-            Theron::AMQ::NetworkLayer::TopicSubscription::Action::CloseSubscription,
-            std::string( MetricValueRootString ) + TheMetric ), 
-            GetSessionLayerAddress() );
-
-          MetricValues.erase( TheMetric );
-        }
     }
+
+    // There could be some metric value records that were defined by the
+    // previous metrics defined, but missing from the new metric set. If 
+    // this is the case, the metric value records for the missing metrics
+    // should be unsubcribed and their metric records removed.
+
+    for( const auto & TheMetric : std::views::keys( MetricValues ) )
+      if( !TheMetricNames.contains( TheMetric ) )
+      {
+        Send( Theron::AMQ::NetworkLayer::TopicSubscription( 
+          Theron::AMQ::NetworkLayer::TopicSubscription::Action::CloseSubscription,
+          std::string( MetricValueRootString ) + TheMetric ), 
+          GetSessionLayerAddress() );
+
+        MetricValues.erase( TheMetric );
+      }
   }
   else
   {
@@ -99,7 +98,8 @@ void MetricUpdater::AddMetricSubscription( const MetricTopic & TheMetrics,
 
     ErrorMessage << "[" << Location.file_name() << " at line " << Location.line() 
                 << " in function " << Location.function_name() <<"] " 
-                << "The message to define a new metric subscription is given as "
+                << "The message to define the application's execution context "
+                << "was given as: " << std::endl
                 << std::endl << TheMetrics.dump(2) << std::endl
                 << "this is not as expected!";
 
@@ -163,8 +163,11 @@ void MetricUpdater::UpdateMetricValue(
 // must look for this identifier type on the solutions in order to decide 
 // which solutions to deploy.
 //
-// The message will be ignored if not all metric values have been received, 
+// The message will be ignored if not all metric values have been received 
-// and no error message indication will be given.
+// or if there are no metric values defined. In both cases the SLO violation 
+// message will just be ignored. In order to avoid the scan over all metrics
+// to see if they are set, a boolean flag will be used and set once all metrics
+// have values. Then future scans will be avoided.
 
 void MetricUpdater::SLOViolationHandler( 
      const SLOViolation & SeverityMessage, const Address TheSLOTopic )
@@ -173,23 +176,49 @@ void MetricUpdater::SLOViolationHandler(
   Output << "Metric Updater: SLO violation received " << std::endl
          << SeverityMessage.dump(2) << std::endl;
 
-  // The application context can then be sent to the solution manager 
+  if( !ReconfigurationInProgress && 
-  // using the application execution context message provided that none of 
+     ( AllMetricValuesSet || 
-  // metric values are null indicating that no value has been received (yet)
+      (!MetricValues.empty() &&
-  // Thus, only if all metrics have values will the message be sent.
+        std::ranges::none_of( std::views::values( MetricValues ), 
-
+        [](const auto & MetricValue){ return MetricValue.is_null(); }  ))) )
-  if( !MetricValues.empty() &&
+  {
-      std::ranges::none_of( MetricValues, 
-      [](const auto & MetricRecord){ return MetricRecord.second.is_null(); } ))
     Send( Solver::ApplicationExecutionContext(
       SeverityMessage.at( NebulOuS::TimePoint ).get< Solver::TimePointType >(),
       MetricValues, true
     ), TheSolverManager );
+
+    AllMetricValuesSet        = true;
+    ReconfigurationInProgress = true;
+  }
   else
     Output << "... failed to forward the application execution context (size: " 
            << MetricValues.size() << ")" << std::endl;
 }
 
+// --------------------------------------------------------------------------
+// Reconfigured application
+// --------------------------------------------------------------------------
+//
+// When the reconfiguration message is received it is an indication tha the 
+// Optimiser Controller has reconfigured the application and that the 
+// application is running in the new configuration found by the solver. 
+// It is the event that is important m not the content of the message, and 
+// it is therefore only used to reset the ongoing reconfiguration flag.
+
+void MetricUpdater::ReconfigurationDone( 
+     const ReconfigurationMessage & TheReconfiguraton, 
+     const Address TheReconfigurationTopic )
+{
+  Theron::ConsoleOutput Output;
+
+  ReconfigurationInProgress = false;
+
+  Output << "Reconfiguration ongoing flag reset after receiving the following "
+         << "message indicating that the previous reconfiguration was"
+         << "completed: " << std::endl
+         << TheReconfiguraton.dump(2) << std::endl;
+}
+
 // --------------------------------------------------------------------------
 // Constructor and destructor
 // --------------------------------------------------------------------------
@@ -199,28 +228,39 @@ void MetricUpdater::SLOViolationHandler(
 // The message handlers are registered, and the the updater will then subscribe
 // to the two topics published by the Optimisation Controller: One for the 
 // initial message defining the metrics and the associated topics to subscribe
-// to for their values, and the second for receiving the SLO violation message.
+// to for their values, and the second to know when a reconfiguration has been 
+// enacted based on a previously sent application execution context. One 
+// subscritpion is also made to receive the SLO violation message indicating 
+// that the running configuration is no longer valid and that a reconfiguration
+// must be made.
 
 MetricUpdater::MetricUpdater( const std::string UpdaterName, 
                               const Address ManagerOfSolvers )
 : Actor( UpdaterName ),
   StandardFallbackHandler( Actor::GetAddress().AsString() ),
   NetworkingActor( Actor::GetAddress().AsString() ),
-  MetricValues(), ValidityTime(0), TheSolverManager( ManagerOfSolvers ),
+  MetricValues(), ValidityTime(0), AllMetricValuesSet(false),
-  MetricsVersion(-1)
+  TheSolverManager( ManagerOfSolvers ),
+  ReconfigurationInProgress( false )
 {
   RegisterHandler( this, &MetricUpdater::AddMetricSubscription );
   RegisterHandler( this, &MetricUpdater::UpdateMetricValue     );
   RegisterHandler( this, &MetricUpdater::SLOViolationHandler   );
+  RegisterHandler( this, &MetricUpdater::ReconfigurationDone   );
 
   Send( Theron::AMQ::NetworkLayer::TopicSubscription(
     Theron::AMQ::NetworkLayer::TopicSubscription::Action::Subscription,
-    std::string( NebulOuS::MetricSubscriptions ) ), 
+    NebulOuS::MetricSubscriptions ), 
     GetSessionLayerAddress() );
 
   Send( Theron::AMQ::NetworkLayer::TopicSubscription(
     Theron::AMQ::NetworkLayer::TopicSubscription::Action::Subscription,
-    std::string( NebulOuS::SLOViolationTopic ) ), 
+    NebulOuS::ReconfigurationTopic ), 
+    GetSessionLayerAddress() );
+
+  Send( Theron::AMQ::NetworkLayer::TopicSubscription(
+    Theron::AMQ::NetworkLayer::TopicSubscription::Action::Subscription,
+    NebulOuS::SLOViolationTopic ), 
     GetSessionLayerAddress() ); 
 }
 
@@ -235,12 +275,17 @@ MetricUpdater::~MetricUpdater()
   {
     Send( Theron::AMQ::NetworkLayer::TopicSubscription(
       Theron::AMQ::NetworkLayer::TopicSubscription::Action::CloseSubscription,
-      std::string( NebulOuS::MetricSubscriptions ) ), 
+      NebulOuS::MetricSubscriptions ), 
       GetSessionLayerAddress() );
 
     Send( Theron::AMQ::NetworkLayer::TopicSubscription(
       Theron::AMQ::NetworkLayer::TopicSubscription::Action::CloseSubscription,
-      std::string( NebulOuS::SLOViolationTopic ) ), 
+      NebulOuS::ReconfigurationTopic ), 
+      GetSessionLayerAddress() );
+
+    Send( Theron::AMQ::NetworkLayer::TopicSubscription(
+      Theron::AMQ::NetworkLayer::TopicSubscription::Action::CloseSubscription,
+      NebulOuS::SLOViolationTopic ), 
       GetSessionLayerAddress() );  
 
     std::ranges::for_each( std::views::keys( MetricValues ),

MetricUpdater.hpp

@@ -88,16 +88,14 @@ constexpr std::string_view TimePoint  = "predictionTime";
 // defined next.
 
 constexpr std::string_view MetricSubscriptions 
-          = "eu.nebulouscloud.monitoring.metric_list";
+          = "eu.nebulouscloud.optimiser.controller.metric_list";
 
 // The JSON message attribute for the list of metrics is another JSON object
 // stored under the following key, see the Event type III defined in 
 // https://158.39.75.54/projects/nebulous-collaboration-hub/wiki/slo-severity-based-violation-detector
 // where the name of the metric is defined under as sub-key.
 
-constexpr std::string_view MetricList = "metric_list",
+constexpr std::string_view MetricList = "metrics";
-                           MetricName = "name",
-                           MetricVersionCounter = "version";
 
 // The metric value messages will be published on different topics and to 
 // check if an inbound message is from a metric value topic, it is necessary 
@@ -130,6 +128,14 @@ constexpr std::string_view MetricValueRootString
 constexpr std::string_view SLOViolationTopic 
           = "eu.nebulouscloud.monitoring.slo.severity_value";
 
+// When a reconfiguration has been enacted by the Optimiser Controller and 
+// a new configuration is confirmed to be running on the new platofrm, it will 
+// send a message to inform all other components that the reconfiguration 
+// has happened on the following topic.
+
+constexpr std::string_view ReconfigurationTopic
+          = "eu.nebulouscloud.optimiser.adaptations";
+
 /*==============================================================================
 
  Metric Updater
@@ -159,7 +165,7 @@ private:
   // assumed that same metric name is used both for the optimisation model 
   // and for the metric topic.
 
-  std::unordered_map< Theron::AMQ::TopicName, JSON > MetricValues;
+  Solver::MetricValueType MetricValues;
 
   // The metric values should ideally be forecasted for the same future time
   // point, but this may not be assured, and as such a zero-order hold is 
@@ -172,24 +178,26 @@ private:
 
   Solver::TimePointType ValidityTime;
 
-  // When an SLO violation message is received the current vector of metric 
+  // There is also a flag to indicate when all metric values have received 
-  // values should be sent as an application execution context (message) to the
+  // values since optimising for a application execution context defiend all 
-  // Solution Manager actor that will invoke a solver to find the optimal 
+  // metrics requires that at least one value is received for each metric. This
-  // configuration for this configuration. The Metric Updater must therefore 
+  // condition could be tested before sending the request to find a new 
-  // know the address of the Soler Manager, and this must be passed to 
+  // solution, but this means testing all metrics in a linear scan for a 
-  // the constructor.
+  // condition that will only happen initially until all metrics have been seen
+  // and so it is better for the performance if there is a flag to check for 
+  // this condition.
 
-  const Address TheSolverManager;
+  bool AllMetricValuesSet;
 
   // --------------------------------------------------------------------------
   // Subscribing to metric prediction values
   // --------------------------------------------------------------------------
   //
   // Initially, the Optimiser Controller will pass a message containing all 
-  // optimiser metric names and the AMQ topic on which their values will be 
+  // optimiser metric names that are used in the optimisation and therefore 
-  // published. Essentially, these messages arrives as a JSON message with 
+  // constitutes the application's execution context. This message is a simple
-  // one attribute per metric, and where the value is the topic string for 
+  // JSON map containing an array since the Optimiser Controller is not able
-  // the value publisher.
+  // to send just an array.
 
   class MetricTopic
   : public Theron::AMQ::JSONTopicMessage
@@ -211,22 +219,12 @@ private:
     virtual ~MetricTopic() = default;
   };
 
-  // The metric definition message "Event type III" of the EMS is sent every 
-  // 60 seconds in order to inform new components or crashed components about
-  // the metrics. The version number of the message is a counter that indicates
-  // if the set of metrics has changed. Thus the message should be ignored 
-  // as long as the version number stays the same. The version number of the
-  // current set of metrics is therefore cached to avoid redefining the 
-  // metrics.
-
-  long int MetricsVersion;
-
   // The handler for this message will check each attribute value of the 
   // received JSON struct, and those not already existing in the metric 
   // value map be added and a subscription made for the published 
   // prediction values.
 
-  void AddMetricSubscription( const MetricTopic & TheMetrics, 
+  void AddMetricSubscription( const MetricTopic & MetricDefinitions, 
                               const Address OptimiserController );
 
   // --------------------------------------------------------------------------
@@ -296,6 +294,52 @@ private:
   void SLOViolationHandler( const SLOViolation & SeverityMessage, 
                             const Address TheSLOTopic );
 
+  // The application execution context (message) will be sent to the
+  // Solution Manager actor that will invoke a solver to find the optimal 
+  // configuration for this configuration. The Metric Updater must therefore 
+  // know the address of the Solver Manager, and this must be passed to 
+  // the constructor and stored for for the duration of the execution
+
+  const Address TheSolverManager;
+
+  // After the sending of the application's excution context, one should not 
+  // initiate another reconfiguration because the state may the possibly be 
+  // inconsistent with the SLO Violation Detector belieivng that the old 
+  // configuration is still in effect while the new configuration is being 
+  // enacted. It is therefore a flag that will be set by the SLO Violation 
+  // handler indicating that a reconfiguration is ongoing.
+
+  bool ReconfigurationInProgress;
+
+  // When the reconfiguration has been done and the Optimizer Controller 
+  // confirms that the application is running in a new configuration, it will 
+  // send a reconfiguration completed message. This message will just be a 
+  // JSON message.
+
+  class ReconfigurationMessage
+  : public Theron::AMQ::JSONTopicMessage
+  { 
+  public:
+
+    ReconfigurationMessage( void )
+    : JSONTopicMessage( std::string( ReconfigurationTopic ) )
+    {}
+
+    ReconfigurationMessage( const ReconfigurationMessage & Other )
+    : JSONTopicMessage( Other )
+    {}
+
+    virtual ~ReconfigurationMessage() = default;
+  };
+
+  // The handler for this message will actually not use its contents, but only
+  // note that the reconfiguration has been completed to reset the 
+  // reconfiguration in progress flag allowing future SLO Violation Events to 
+  // triger new reconfigurations.
+
+  void ReconfigurationDone( const ReconfigurationMessage & TheReconfiguraton, 
+                            const Address TheReconfigurationTopic );
+
   // --------------------------------------------------------------------------
   // Constructor and destructor
   // --------------------------------------------------------------------------

Solver.code-workspace

@@ -91,7 +91,8 @@
 			"valarray": "cpp",
 			"bitset": "cpp",
 			"regex": "cpp",
-			"syncstream": "cpp"
+			"syncstream": "cpp",
+			"expected": "cpp"
 		},
 		"gerrit.gitRepo": "/home/GHo/Documents/Code/NebulOuS/Solvers"
 	}

Solver.hpp

@@ -155,14 +155,20 @@ public:
   {
   public:
 
-    static constexpr std::string_view MessageIdentifier 
+    // First the topic on which these messages will arrive is defined so that 
+    // it can be used when subscribing.
+
+    static constexpr std::string_view AMQTopic 
                      = "eu.nebulouscloud.optimiser.solver.context";
 
+    // The full constructor takes the time point, the objective function to 
+    // solve for, and the application's execution context as the metric map
+
     ApplicationExecutionContext( const TimePointType MicroSecondTimePoint,
                                  const std::string ObjectiveFunctionID,
                                  const MetricValueType & TheContext,
                                  bool DeploySolution = false )
-    : JSONTopicMessage( std::string( MessageIdentifier ),
+    : JSONTopicMessage( std::string( AMQTopic ),
     { { std::string( TimeStamp ), MicroSecondTimePoint },
       { std::string( ObjectiveFunctionLabel ), ObjectiveFunctionID },
       { std::string( ExecutionContext ), TheContext },
@@ -170,12 +176,13 @@ public:
     }) {}
 
     // The constructor omitting the objective function identifier is similar
-    // but without the objective function string.
+    // but without the objective function string implying that the default
+    // objective function should be used.
 
     ApplicationExecutionContext( const TimePointType MicroSecondTimePoint,
                                  const MetricValueType & TheContext,
                                  bool DeploySolution = false )
-    : JSONTopicMessage( std::string( MessageIdentifier ),
+    : JSONTopicMessage( std::string( AMQTopic ),
     { { std::string( TimeStamp ), MicroSecondTimePoint },
       { std::string( ExecutionContext ), TheContext },
       { std::string( DeploymentFlag ), DeploySolution }
@@ -191,7 +198,7 @@ public:
     // The default constructor simply stores the message identifier
 
     ApplicationExecutionContext()
-    : JSONTopicMessage( std::string( MessageIdentifier ) )
+    : JSONTopicMessage( std::string( AMQTopic ) )
     {}
 
     // The default destrucor is used
@@ -240,7 +247,7 @@ public:
     static constexpr std::string_view ObjectiveValues = "ObjectiveValues";
     static constexpr std::string_view VariableValues  = "VariableValues";
 
-    static constexpr std::string_view MessageIdentifier 
+    static constexpr std::string_view AMQTopic 
                      = "eu.nebulouscloud.optimiser.solver.solution";
 
     Solution( const TimePointType MicroSecondTimePoint,
@@ -248,7 +255,7 @@ public:
               const ObjectiveValuesType & TheObjectiveValues,
               const VariableValuesType & TheVariables,
               bool DeploySolution )
-    : JSONTopicMessage( std::string( MessageIdentifier ) ,
+    : JSONTopicMessage( std::string( AMQTopic ) ,
       { { std::string( TimeStamp ), MicroSecondTimePoint   },
         { std::string( ObjectiveFunctionLabel ), ObjectiveFunctionID },
         { std::string( ObjectiveValues ) , TheObjectiveValues },
@@ -258,7 +265,7 @@ public:
       {}
     
     Solution()
-    : JSONTopicMessage( std::string( MessageIdentifier ) )
+    : JSONTopicMessage( std::string( AMQTopic ) )
     {}
 
     virtual ~Solution() = default;
@@ -279,15 +286,15 @@ public:
   {
   public:
 
-    static constexpr std::string_view 
+    static constexpr std::string_view AMQTopic 
-           MessageIdentifier    = "eu.nebulouscloud.optimiser.solver.model";
+           = "eu.nebulouscloud.optimiser.controller.model";
 
     OptimisationProblem( const JSON & TheProblem )
-    : JSONTopicMessage( std::string( MessageIdentifier ), TheProblem )
+    : JSONTopicMessage( std::string( AMQTopic ), TheProblem )
     {}
 
     OptimisationProblem()
-    : JSONTopicMessage( std::string( MessageIdentifier ) )
+    : JSONTopicMessage( std::string( AMQTopic ) )
     {}
 
     virtual ~OptimisationProblem() = default;
@@ -326,7 +333,7 @@ public:
 
     Send( Theron::AMQ::NetworkLayer::TopicSubscription(
       Theron::AMQ::NetworkLayer::TopicSubscription::Action::Subscription,
-      Theron::AMQ::TopicName( OptimisationProblem::MessageIdentifier )
+      OptimisationProblem::AMQTopic
     ), GetSessionLayerAddress() );
   }
   
@@ -337,7 +344,7 @@ public:
     if( HasNetwork() )
       Send( Theron::AMQ::NetworkLayer::TopicSubscription(
         Theron::AMQ::NetworkLayer::TopicSubscription::Action::CloseSubscription,
-        Theron::AMQ::TopicName( OptimisationProblem::MessageIdentifier )
+        OptimisationProblem::AMQTopic
       ), GetSessionLayerAddress() );
   }
 };

SolverComponent.cpp

@@ -95,6 +95,7 @@ License: MPL2.0 (https://www.mozilla.org/en-US/MPL/2.0/)
 #include "proton/message.hpp"                   // AMQ messages definitions
 #include "proton/source_options.hpp"            // App ID filters
 #include "proton/source.hpp"                    // The filter map
+#include "proton/types.hpp"                     // Type definitions
 #include "Communication/AMQ/AMQMessage.hpp"     // The AMQP messages
 #include "Communication/AMQ/AMQEndpoint.hpp"    // The AMP endpoint
 #include "Communication/AMQ/AMQjson.hpp"        // Transparent JSON-AMQP
@@ -213,8 +214,7 @@ int main( int NumberOfCLIOptions, char ** CLIOptionStrings )
 
     virtual proton::connection_options ConnectionOptions(void) const override
     {
-      proton::connection_options Options( 
+      proton::connection_options Options( AMQProperties::ConnectionOptions() );
-            Theron::AMQ::NetworkLayer::AMQProperties::ConnectionOptions() );
 
       Options.user( User );
       Options.password( Password );
@@ -235,8 +235,7 @@ int main( int NumberOfCLIOptions, char ** CLIOptionStrings )
       proton::symbol             FilterKey("selector");
       proton::value              FilterValue;
       proton::codec::encoder     EncodedFilter( FilterValue );
-      proton::receiver_options   TheOptions( 
+      proton::receiver_options   TheOptions( AMQProperties::ReceiverOptions() );
-              Theron::AMQ::NetworkLayer::AMQProperties::ReceiverOptions() );
 
       std::ostringstream SelectorString;
 
@@ -255,17 +254,18 @@ int main( int NumberOfCLIOptions, char ** CLIOptionStrings )
     }
 
     // The application identifier must also be provided in every message to 
-    // allow other receivers to filter on this.
+    // allow other receivers to filter on this. First will the default 
+    // properties from the base class be set before the new application 
+    // identifier property will be added.
 
-    virtual proton::message::property_map MessageProperties( 
+    virtual std::map<std::string, proton::scalar> MessageProperties( 
       const proton::message::property_map & CurrentProperties 
           = proton::message::property_map() ) const override
     {
-      proton::message::property_map TheProperties( 
+      std::map<std::string, proton::scalar> 
-        Theron::AMQ::NetworkLayer::AMQProperties::MessageProperties( 
+      TheProperties( AMQProperties::MessageProperties( CurrentProperties ) );
-          CurrentProperties ));
+
-      
+      TheProperties["application"] = ApplicationID;
-      TheProperties.put( "application", ApplicationID );
 
       return TheProperties;
     }
@@ -332,8 +332,8 @@ int main( int NumberOfCLIOptions, char ** CLIOptionStrings )
 
   NebulOuS::SolverManager< NebulOuS::AMPLSolver > 
   WorkloadMabager( CLIValues["Name"].as<std::string>(), 
-    std::string( NebulOuS::Solver::Solution::MessageIdentifier ), 
+    NebulOuS::Solver::Solution::AMQTopic, 
-    std::string( NebulOuS::Solver::ApplicationExecutionContext::MessageIdentifier ),
+    NebulOuS::Solver::ApplicationExecutionContext::AMQTopic,
     1, "AMPLSolver", 
     ampl::Environment( TheAMPLDirectory.native() ), ModelDirectory, 
     CLIValues["Solver"].as<std::string>() );

SolverManager.hpp

@@ -193,7 +193,7 @@ private:
   void PublishSolution( const Solver::Solution & TheSolution, 
                         const Address TheSolver )
   {
-    Send( TheSolution, SolutionReceiver );
+    Send( TheSolution, Address( SolutionReceiver ) );
     PassiveSolvers.insert( ActiveSolvers.extract( TheSolver ) );
     DispatchToSolvers();
   }
@@ -274,7 +274,7 @@ public:
 
       Send( ExecutionControl::StatusMessage(
         ExecutionControl::StatusMessage::State::Started
-      ), Address( std::string( ExecutionControl::StatusTopic ) ) );
+      ), Address( ExecutionControl::StatusMessage::AMQTopic ) );
     }
     else
     {