长跑WF 4模式

Question

我想要实现以下目标:

1. 启动可能会长时间运行的工作流程,其中包括自定义活动;
2. 这些自定义活动将遵循创建书签和等待其简历的模式;
3. 返回已启动的工作流程ID并将其存储在某处;
4. 在以后的某个时间点,从其存储的ID加载工作流程;
5. 检查工作流程是否已完成,如果没有,请检查是否有任何被阻止的书签;
6. 恢复这些书签,从而导致相关活动完成,最终导致完整的工作流程完成.

一个简单的用例是:用于审阅文档并批准或拒绝文档的工作流程.将为此创建工作流程,将通知个人,并且只要他们想要,他们就可以通过批准或拒绝审核来提供他们的反馈.

我以Andrew Zhu的代码为例,可以在http://xhinker.com/post/WF4.aspx上找到.

我遇到的问题是:

1. 当使用我所描述的自定义活动时,在启动工作流时,WaitForRunnableInstance无限期等待,因此我从未收到通知我的工作流程已启动并持久保存到数据库;
2. 确实存储了工作流,并将列BlockingBookmarks设置为我的自定义活动的id,ExecutionStatus设置为Idle,IsInitialized设置为1,IsSuspended设置为0,IsCompleted设置为0并IsReadyToRun设置为0.

我已经开始讨论微软论坛,可以在http://social.msdn.microsoft.com/Forums/en-US/wfprerelease/thread/6262874d-3493-4be1-bd05-b990307e1875/上看到并得到一些反馈,但有些事情仍然不对.

有什么想法吗？使用自定义活动的长时间运行工作流的任何有用模式？

谢谢!

Answer 1

这通常是长时间运行的工作流的最小示例,它等待控制台上的用户输入.(此代码从未执行过,仅作为示例)

/// Activity that waits on bookmark for
/// someone to send it some text
///
public sealed class ReadLine: NativeActivity<string>
{
    [RequiredArgument]
    public InArgument<string> BookmarkName { get; set; }

    protected override bool CanInduceIdle 
    {
        get
        {
            return true;
        }
    }

    protected override void Execute(NativeActivityContext context)
    {
        context.CreateBookmark(
            BookmarkName.Get(context), 
            new BookmarkCallback(OnReadComplete));
    }

    void OnReadComplete(NativeActivityContext context, Bookmark bookmark, object state)
    {
        context.SetValue(base.Result, state as string);
    }
}

/// Program that uses ReadLine activity's bookmark to persist
/// workflow and waits for user input to resume it
///
public class Program
{
    static InstanceStore InstanceStore;
    static Activity Activity = GetExampleActivity();
    static AutoResetEvent unloadEvent = new AutoResetEvent(false);
    static Guid WfId;
    static WorkflowApplication WfApp;

    const string READ_LINE_BOOKMARK = "ReadLineBookMark";

    static void Main()
    {
        CreateInstanceStore();
        CreateWorkflowApp();

        // Start workflow application and wait for input
        StartAndUnload();

        //Get user input and send it to ReadLine bookmark reviving workflow
        GetInputAndComplete();
    }

    static void StartAndUnload()
    {
        WfApp.Run();
        WfId = app.Id;
        // !! Workflow will go idle on bookmark, no need to call Unload()
        unloadEvent.WaitOne();
    }

    static void GetInputAndComplete() 
    {
        var input = Console.ReadLine();

        // We've the text input, let's resume this thing
        WfApp.Load(WfId);
        WfApp.ResumeBookmark(READ_LINE_BOOKMARK, input);

        unloadEvent.WaitOne();
    }

    static void CreateInstanceStore()
    {
        InstanceStore = new SqlWorkflowInstanceStore("connection string");

        var handle = InstanceStore.CreateInstanceHandle();            
        var view = InstanceStore.Execute(
            handle, 
            new CreateWorkflowOwnerCommand(), 
            TimeSpan.FromSeconds(5));            

        handle.Free();

        InstanceStore.DefaultInstanceOwner = view.InstanceOwner;
    }

    static void CreateWorkflowApp()
    {
        WfApp = new WorkflowApplication(Activity)
        {
            InstanceStore = InstanceStore,
        };

        WfApp.PersistableIdle = (e) => { return PersistableIdleAction.Unload; }
        WfApp.Unloaded = (e) => 
        { 
            Console.WriteLine("WF App Unloaded\n");
            unloadEvent.Set(); 
        };
        WfApp.Completed = (e) =>
        {
            Console.WriteLine("\nWF App Ended: {0}.", e.CompletionState);
        };
    }

    static Activity GetExampleActivity()
    {
        var response = new Variable<string>();

        return return new Sequence()
        {
            Variables = { response },
            Activities = 
            { 
                new WriteLine()
                { 
                    Text = new InArgument<string>("Type some word:") 
                },
                new ReadLine() 
                { 
                    BookmarkName = READ_LINE_BOOKMARK, 
                    Result = new OutArgument<string>(response)
                },
                new WriteLine()
                {
                    Text = new InArgument<string>((context) => "You've typed: " + response.Get(context))
                }
            }
        };
    }

话虽如此,请考虑使用IIS和AppFabric,你不会后悔.AppFabric,点击了6次,负责在WF中实现两个必须痛苦的事情:持久性和监控.如果选择此路径,您将永远不需要编写代码.

将您的工作流部署为WCF应用程序,您只需将其称为任何其他WCF合同.你有OperationContracts是接收活动(那些等待和持久,如果它需要太长时间)和相应的发送活动(那些将值返回给客户端).你甚至有他们之间的相关概念.AppFabric负责恢复工作流程,只需将之前初始化的关联句柄传递给它.

AppFabric为您提供配置UI,用于配置持久性存储,监控和其他选项,例如空闲和/或持续之前的时间.

您可以可视化Active/Idle/Suspended工作流,监控数据等.