新增自訂工作中的偵錯支援
Integration Services 執行階段引擎允許在執行期間，使用中斷點暫停封裝、工作和其他類型的容器。使用中斷點可讓您檢閱和修正妨礙應用程式或工作正確執行的錯誤。中斷點架構可讓用戶端在定義的執行點暫停工作處理，以評估封裝中物件的執行階段值。
自訂工作開發人員可以使用 IDTSBreakpointSite 介面及其父介面 IDTSSuspend，以利用此架構建立自訂中斷點目標。IDTSBreakpointSite 介面會定義執行階段引擎與工作之間的互動，以建立和管理自訂中斷點位置或目標。IDTSSuspend 介面提供執行階段引擎呼叫的方法與屬性，通知工作暫停或是繼續其執行。
中斷點位置或目標是在工作執行中可以暫停處理的點。使用者可以從 [設定中斷點] 對話方塊中的可用中斷點位置選取。例如，除了預設中斷點選項之外，[Foreach 迴圈容器] 提供 [在迴圈的每一次反覆運算開始時中斷] 選項。
當工作在執行期間到達中斷點目標時，它會評估中斷點目標以決定是否啟用中斷點。這指出使用者希望在該中斷點停止執行。如果啟用中斷點，工作會將 OnBreakpointHit 事件引發至執行階段引擎。執行階段引擎會呼叫目前在封裝中執行的每項工作之 Suspend 方法以回應事件。當執行階段呼叫已暫停工作的 ResumeExecution 方法時，工作執行會繼續。
不使用中斷點的工作仍應實作 IDTSBreakpointSite 與 IDTSSuspend 介面。這可確保當封裝中的其他物件引發 OnBreakpointHit 事件時，正確地暫停工作。
IDTSBreakpointSite 介面與 BreakpointManager
工作透過呼叫 BreakpointManager 的 CreateBreakpointTarget 方法，並提供整數識別碼和字串描述做為參數，以建立中斷點目標。當工作到達其程式碼中包含中斷點目標的點時，它會使用 IsBreakpointTargetEnabled 方法評估中斷點目標，以判斷是否已啟用該中斷點。如果是 true，工作會引發 OnBreakpointHit 事件，以通知執行階段引擎。
IDTSBreakpointSite 介面會定義單一方法 AcceptBreakpointManager，後者會由執行階段引擎於工作建立期間呼叫。這個方法會以參數形式提供 BreakpointManager 物件，然後由工作使用該物件來建立並管理其中斷點。工作會在本機上儲存 BreakpointManager，以供在 Validate 與 Execute 方法期間使用。
下列範例程式碼示範如何使用 BreakpointManager 來建立中斷點目標。範例會呼叫 OnBreakpointHit 方法以引發事件。
public void AcceptBreakpointManager( BreakpointManager breakPointManager )
{
// Store the breakpoint manager locally.
this.bpm = breakPointManager;
}
public override DTSExecResult Execute( Connections connections,
Variables variables, IDTSComponentEvents events,
IDTSLogging log, DtsTransaction txn)
{
// Create a breakpoint.
this.bpm.CreateBreakPointTarget( 1 , "A sample breakpoint target." );
...
if( this.bpm.IsBreakpointTargetEnabled( 1 ) == true )
events.OnBreakpointHit( this.bpm.GetBreakpointTarget( 1 ) );
}
Public Sub AcceptBreakpointManager(ByVal breakPointManager As BreakpointManager)
' Store the breakpoint manager locally.
Me.bpm = breakPointManager
End Sub
Public Overrides Function Execute(ByVal connections As Connections, _
ByVal variables As Variables, ByVal events As IDTSComponentEvents, _
ByVal log As IDTSLogging, ByVal txn As DtsTransaction) As DTSExecResult
' Create a breakpoint.
Me.bpm.CreateBreakPointTarget(1 , "A sample breakpoint target.")
If Me.bpm.IsBreakpointTargetEnabled(1) = True Then
events.OnBreakpointHit(Me.bpm.GetBreakpointTarget(1))
End If
End Function
IDTSSuspend 介面
IDTSSuspend 介面會定義當執行階段引擎暫停或是繼續工作的執行時，該引擎呼叫的方法。IDTSSuspend 介面是由 IDTSBreakpointSite 介面實作，而且自訂工作通常會覆寫其 Suspend 與 ResumeExecution 方法。當執行階段引擎從工作收到 OnBreakpointHit 事件時，它會呼叫每個執行中工作的 Suspend 方法，以通知工作暫停。當用戶端繼續執行時，執行階段引擎會呼叫已暫停工作的 ResumeExecution 方法。
暫停和繼續工作執行需要暫停和繼續工作的執行緒。在 Managed 程式碼中，您使用 .NET Framework 之 System.Threading 命名空間中的 ManualResetEvent 類別，來執行這項動作。
下列程式碼範例示範工作執行的暫停與繼續。請注意，Execute 方法和上一個程式碼範例不同，而且會在引發中斷點時暫停執行緒。
private ManualResetEvent m_suspended = new ManualResetEvent( true );
private ManualResetEvent m_canExecute = new ManualResetEvent( true );
private int m_suspendRequired = 0;
private int m_debugMode = 0;
public override DTSExecResult Execute( Connections connections, Variables variables, IDTSComponentEvents events, IDTSLogging log, DtsTransaction txn)
{
// While a task is not executing, it is suspended.
// Now that we are executing,
// change to not suspended.
ChangeEvent(m_suspended, false);
// Check for a suspend before doing any work,
// in case the suspend and execute calls
// were initiated at virtually the same time.
CheckAndSuspend();
CheckAndFireBreakpoint( componentEvents, 1);
}
private void CheckAndSuspend()
{
// Loop until we can execute.
// The loop is required rather than a simple If
// because there is a time between the return from WaitOne and the
// reset that we might receive another Suspend call.
// Suspend() will see that we are suspended
// and return. So we need to rewait.
while (!m_canExecute.WaitOne(0, false))
{
ChangeEvent(m_suspended, true);
m_canExecute.WaitOne();
ChangeEvent(m_suspended, false);
}
}
private void CheckAndFireBreakpoint(IDTSComponentEvents events, int breakpointID)
{
// If the breakpoint is enabled, fire it.
if (m_debugMode != 0 && this.bpm.IsBreakpointTargetEnabled(breakpointID))
{
// Enter a suspend mode before firing the breakpoint.
// Firing the breakpoint will cause the runtime
// to call Suspend on this task.
// Because we are blocked on the breakpoint,
// we are suspended.
ChangeEvent(m_suspended, true);
events.OnBreakpointHit(this.bpm.GetBreakpointTarget(breakpointID));
ChangeEvent(m_suspended, false);
}
// Check for a suspension for two reasons:
// 1. If we are at a point where we could fire a breakpoint,
// we are at a valid suspend point. Even if we didn't hit a
// breakpoint, the runtime may have called suspend,
// so check for it.
// 2. Between the return from OnBreakpointHit
// and the reset of the event, it is possible to have
// received a suspend call from which we returned because
// we were already suspended. We need to be sure it is okay
// to continue executing now.
CheckAndSuspend();
}
static void ChangeEvent(ManualResetEvent e, bool shouldSet)
{
bool succeeded;
if (shouldSet)
succeeded = e.Set();
else
succeeded = e.Reset();
if (!succeeded)
throw new Exception("Synchronization object failed.");
}
public bool SuspendRequired
{
get {return m_suspendRequired != 0;}
set
{
// This lock is also taken by Suspend().
// Because it is possible for the package to be
// suspended and resumed in quick succession,
// this property might be set before
// the actual Suspend() call.
// Without the lock, the Suspend() might reset the canExecute
// event after we set it to abort the suspension.
lock (this)
{
Interlocked.Exchange(ref m_suspendRequired, value ? 1 : 0);
if (!value)
ResumeExecution();
}
}
}
public void ResumeExecution()
{
ChangeEvent( m_canExecute,true );
}
public void Suspend()
{
// This lock is also taken by the set SuspendRequired method.
// It prevents this call from overriding an
// aborted suspension. See comments in set SuspendRequired.
lock (this)
{
// If a Suspend is required, do it.
if (m_suspendRequired != 0)
ChangeEvent(m_canExecute, false);
}
// We can't return from Suspend until the task is "suspended".
// This can happen one of two ways:
// the m_suspended event occurs, indicating that the execute thread
// has suspended, or the canExecute flag is set,
// indicating that a suspend is no longer required.
WaitHandle [] suspendOperationComplete = {m_suspended, m_canExecute};
WaitHandle.WaitAny(suspendOperationComplete);
}
Private m_suspended As ManualResetEvent = New ManualResetEvent(True)
Private m_canExecute As ManualResetEvent = New ManualResetEvent(True)
Private m_suspendRequired As Integer = 0
Private m_debugMode As Integer = 0
Public Overrides Function Execute(ByVal connections As Connections, _
ByVal variables As Variables, ByVal events As IDTSComponentEvents, _
ByVal log As IDTSLogging, ByVal txn As DtsTransaction) As DTSExecResult
' While a task is not executing it is suspended.
' Now that we are executing,
' change to not suspended.
ChangeEvent(m_suspended, False)
' Check for a suspend before doing any work,
' in case the suspend and execute calls
' were initiated at virtually the same time.
CheckAndSuspend()
CheckAndFireBreakpoint(componentEvents, 1)
End Function
Private Sub CheckAndSuspend()
' Loop until we can execute.
' The loop is required rather than a simple if
' because there is a time between the return from WaitOne and the
' reset that we might receive another Suspend call.
' Suspend() will see that we are suspended
' and return. So we need to rewait.
Do While Not m_canExecute.WaitOne(0, False)
ChangeEvent(m_suspended, True)
m_canExecute.WaitOne()
ChangeEvent(m_suspended, False)
Loop
End Sub
Private Sub CheckAndFireBreakpoint(ByVal events As IDTSComponentEvents, _
ByVal breakpointID As Integer)
' If the breakpoint is enabled, fire it.
If m_debugMode <> 0 AndAlso Me.bpm.IsBreakpointTargetEnabled(breakpointID) Then
' Enter a suspend mode before firing the breakpoint.
' Firing the breakpoint will cause the runtime
' to call Suspend on this task.
' Because we are blocked on the breakpoint,
' we are suspended.
ChangeEvent(m_suspended, True)
events.OnBreakpointHit(Me.bpm.GetBreakpointTarget(breakpointID))
ChangeEvent(m_suspended, False)
End If
' Check for a suspension for two reasons:
' 1. If we are at a point where we could fire a breakpoint,
' we are at a valid suspend point. Even if we didn't hit a
' breakpoint, the runtime may have called suspend,
' so check for it.
' 2. Between the return from OnBreakpointHit
' and the reset of the event, it is possible to have
' received a suspend call from which we returned because
' we were already suspended. We need to be sure it is okay
' to continue executing now.
CheckAndSuspend()
End Sub
Shared Sub ChangeEvent(ByVal e As ManualResetEvent, ByVal shouldSet As Boolean)
Dim succeeded As Boolean
If shouldSet Then
succeeded = e.Set()
Else
succeeded = e.Reset()
End If
If (Not succeeded) Then
Throw New Exception("Synchronization object failed.")
End If
End Sub
Public Property SuspendRequired() As Boolean
Get
Return m_suspendRequired <> 0
End Get
Set
' This lock is also taken by Suspend().
' Because it is possible for the package to be
' suspended and resumed in quick succession,
' this property might be set before
' the actual Suspend() call.
' Without the lock, the Suspend() might reset the canExecute
' event after we set it to abort the suspension.
SyncLock Me
Interlocked.Exchange(m_suspendRequired,IIf(Value, 1, 0))
If (Not Value) Then
ResumeExecution()
End If
End SyncLock
End Set
End Property
Public Sub ResumeExecution()
ChangeEvent(m_canExecute,True)
End Sub
Public Sub Suspend()
' This lock is also taken by the set SuspendRequired method.
' It prevents this call from overriding an
' aborted suspension. See comments in set SuspendRequired.
SyncLock Me
' If a Suspend is required, do it.
If m_suspendRequired <> 0 Then
ChangeEvent(m_canExecute, False)
End If
End SyncLock
' We can't return from Suspend until the task is "suspended".
' This can happen one of two ways:
' the m_suspended event occurs, indicating that the execute thread
' has suspended, or the canExecute flag is set,
' indicating that a suspend is no longer required.
Dim suspendOperationComplete As WaitHandle() = {m_suspended, m_canExecute}
WaitHandle.WaitAny(suspendOperationComplete)
End Sub
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