ClientSuite: Improve WorkerManager

GUIs.ClientSuite/Workers/HeartbeatWorker.vb

@@ -1,47 +1,44 @@
 Imports System.Timers
-Imports DigitalData.GUIs.ClientSuite
 Imports DigitalData.GUIs.ClientSuite.Base
-Imports DigitalData.Modules.EDMIAPI.IDBServiceReference
 Imports DigitalData.Modules.Logging
+
 Namespace Workers
     Public Class HeartbeatWorker
         Inherits BaseClass
         Implements IWorker
 
-        Private _Channel As IIDBServiceChannel
-
         Public Event OnlineChanged As OnlineChangedEventHandler
         Public Delegate Sub OnlineChangedEventHandler(sender As Object, Online As Boolean)
 
         Public ReadOnly Property Interval As Integer = 4000 Implements IWorker.Interval
+        Public ReadOnly Property Name As String = "Heartbeat Worker" Implements IWorker.Name
 
         Public Sub New(LogConfig As LogConfig)
             MyBase.New(LogConfig)
         End Sub
 
         Public Sub Setup() Implements IWorker.Setup
-            _Channel = My.ChannelFactory.CreateChannel()
+            Logger.Debug("Starting {0}", "HeartbeatWorker")
-            _Channel.Open()
         End Sub
 
-        Public Async Sub Callback(manager As WorkerManager, e As ElapsedEventArgs) Implements IWorker.Callback
+        Public Async Sub Callback(Manager As WorkerManager, e As ElapsedEventArgs) Implements IWorker.Callback
             Try
-                Logger.Debug("Checking if Service is up...")
+                If My.Channel.State = ServiceModel.CommunicationState.Faulted Then
-
+                    My.Channel = My.ChannelFactory.CreateChannel()
-                If _Channel.State = ServiceModel.CommunicationState.Faulted Then
-                    _Channel = My.ChannelFactory.CreateChannel()
                 End If
 
                 ' Connect to service and send hearbeat request
-                Dim oResult = Await _Channel.HeartbeatAsync()
+                Dim oResult = Await My.Channel.HeartbeatAsync()
 
                 Logger.Debug("Service is online")
 
                 SetOnlineState(True)
             Catch ex As Exception
+
                 Logger.Debug("Service is offline!")
                 Logger.Error(ex)
 
+                Manager.StopWorkers()
                 SetOnlineState(False)
             Finally
                 My.Application.Service.LastChecked = DateTime.Now
@@ -49,7 +46,7 @@ Namespace Workers
         End Sub
 
         Public Sub Teardown() Implements IWorker.Teardown
-            ' TODO: Close channel gracefully
+            Logger.Debug("Stopping {0}", Name)
         End Sub
 
         Private Sub SetOnlineState(NewState As Boolean)

GUIs.ClientSuite/Workers/IWorker.vb

@@ -3,6 +3,7 @@
 Namespace Workers
     Public Interface IWorker
         ReadOnly Property Interval As Integer
+        ReadOnly Property Name As String
 
         Sub Setup()
         Sub Teardown()

GUIs.ClientSuite/Workers/WorkerManager.vb

@@ -6,6 +6,14 @@ Namespace Workers
     Public Class WorkerManager
         Inherits BaseClass
 
+        ''' <summary>
+        ''' Holds information about a worker
+        ''' </summary>
+        Class WorkerState
+            Public Worker As IWorker
+            Public Timer As Timer
+        End Class
+
         ''' <summary>
         ''' List of workers that will be started.
         ''' </summary>
@@ -13,52 +21,73 @@ Namespace Workers
             GetType(HeartbeatWorker),
             GetType(WorkflowOverviewWorker)
         }
-        Private Workers As New List(Of IWorker)
+        Private Workers As New List(Of WorkerState)
-        Private TimerList As New List(Of Timer)
 
         Public Sub New(LogConfig As LogConfig, SyncronizingObject As frmMain)
             MyBase.New(LogConfig)
 
-            Workers = CreateWorkers()
+            Workers = CreateWorkers(SyncronizingObject)
-
-            For Each oWorker As IWorker In Workers
-                Dim oTimer = New Timer(oWorker.Interval) With {
-                    .SynchronizingObject = SyncronizingObject,
-                    .Enabled = True
-                }
-
-                AddHandler oTimer.Elapsed, Sub(sender As Object, e As ElapsedEventArgs)
-                                               Try
-                                                   oWorker.Callback(Me, e)
-                                               Catch ex As Exception
-                                                   Logger.Warn("Worker {0} threw an error in callback.", oWorker.GetType.Name)
-                                               End Try
-                                           End Sub
-
-                TimerList.Add(oTimer)
-            Next
         End Sub
 
         Public Function GetWorker(Of T)() As T
-            For Each oWorker In Workers
+            For Each oWorkerState As WorkerState In Workers
-                If TypeOf oWorker Is T Then
+                If TypeOf oWorkerState.Worker Is T Then
-                    Return oWorker
+                    Return oWorkerState.Worker
                 End If
             Next
 
             Return Nothing
         End Function
 
-        Private Function CreateWorkers() As List(Of IWorker)
+        Public Sub StopWorkers()
-            Dim oWorkers As New List(Of IWorker)
+            Logger.Debug("Stopping all workers..")
+            For Each oWorkerState In Workers
+                oWorkerState.Timer.Stop()
+
+                Try
+                    oWorkerState.Worker.Teardown()
+                Catch ex As Exception
+                    Logger.Warn("Worker {0} threw an error during teardown.", oWorkerState.Worker.Name)
+                End Try
+            Next
+            Logger.Debug("All workers stopped.")
+        End Sub
+
+        Private Function CreateTimer(Worker As IWorker, SyncronizingObject As frmMain)
+            Dim oTimer = New Timer(Worker.Interval) With {
+                .SynchronizingObject = SyncronizingObject,
+                .Enabled = True
+            }
+
+            AddHandler oTimer.Elapsed, Sub(sender As Object, e As ElapsedEventArgs)
+                                           Try
+                                               Worker.Callback(Me, e)
+                                           Catch ex As Exception
+                                               Logger.Warn("Worker {0} threw an error in callback.", Worker.Name)
+                                               Logger.Error(ex)
+                                           End Try
+                                       End Sub
+
+            Return oTimer
+        End Function
+
+        Private Function CreateWorkers(SyncronizingObject As frmMain) As List(Of WorkerState)
+            Dim oWorkers As New List(Of WorkerState)
 
             For Each oWorkerType In WorkerTypes
+                Dim oWorker As IWorker = Activator.CreateInstance(oWorkerType, New Object() {LogConfig})
+
                 Try
-                    Dim oWorker As IWorker = Activator.CreateInstance(oWorkerType, New Object() {LogConfig})
                     oWorker.Setup()
-                    oWorkers.Add(oWorker)
+
+                    Dim oWorkerState As New WorkerState() With {
+                        .Worker = oWorker,
+                        .Timer = CreateTimer(oWorker, SyncronizingObject)
+                    }
+
+                    oWorkers.Add(oWorkerState)
                 Catch ex As Exception
-                    Logger.Warn("Worker {0} threw an error while creating. Skipping.", oWorkerType.Name)
+                    Logger.Warn("Worker {0} threw an error during setup. Skipping.", oWorker.Name)
                     Logger.Error(ex)
                     Continue For
                 End Try

GUIs.ClientSuite/Workers/WorkflowOverviewWorker.vb

@@ -12,6 +12,7 @@ Namespace Workers
         End Sub
 
         Public ReadOnly Property Interval As Integer = 60000 Implements IWorker.Interval
+        Public ReadOnly Property Name As String = "WorkflowOverview Worker" Implements IWorker.Name
 
         Public Sub Setup() Implements IWorker.Setup
             Throw New NotImplementedException()

GUIs.ClientSuite/frmMain.vb

@@ -37,11 +37,11 @@ Public Class frmMain
     End Sub
 
     Private Sub HandleOnlineChanged(sender As Object, Online As Boolean)
+        SetOnlineLabel(Online)
         If Online = False Then
-
+            MessageBox.Show($"Application will be closed now.{vbNewLine}Reason: Service is offline.", "Critical Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
             Application.Exit()
         End If
-        SetOnlineLabel(Online)
     End Sub
 
     Private Sub FrmMain_Load(sender As Object, e As EventArgs) Handles Me.Load