I have long running workflow which runs for 3-5 minutes; I want to give flexibility to end user to Cancel/Stop/Abort workflow while workflow is in execution. How can I do this ?
Ocean
It depends on your workflow execution environment. If you are using the WorkflowApplication it has methods to control a workflow. If your are using the WorkflowServiceHost there is a Workflow Control Endpoint with a client that will let you do so. See this answer for the WCF option.
Related
I have a web api that's running 24/7 on LAN(due to data security reasons, it's not connected to the internet). I have to call one method inside it each morning around 07:00. I've read that Timers are not reliable. I do not own the server so I don't have access to the Task Scheduler. How can I achieve this?
Do you think I should tell them that I have to install the software? Would they let me use the Task Scheduler? Is there any way to do this without the Task Scheduler?
There are a couple of options that you should look into.
Native .NET Core solution through IHostedService
Hangfire
Personally, I like that you can configure a dashboard and see what happened during the execution of your scheduled tasks.
As suggested by #Lei Yang in the comments, Quartz.NET
Hangfire is still adding in-memory support. Therefore, you're required to have a SQL Server to store all the information about the job (triggers, states, etc.).
This can have a huge impact in your decision. On the other hand, Quartz.NET does support in-memory store type.
Team:
I need to invoke a WF activity (XAML) from a WF service (XAMLX) asynchronously. I am already referencing the Microsoft.Activities.Extensions framework and I'm running on the Platform Update 1 for the state machine -- so if the solution is already in one of those libraries I'm ready!
Now, I need to invoke that activity (XAML) asynchronously -- but it has an output parameter that needs to set a variable in the service (XAMLX). Can somebody please provide me a solution to this?
Thanks!
* UPDATE *
Now I can post pictures, * I think *, because I have enough reputation! Let me put a couple out here and try to better explain my problem. The first picture is the WF Service that has the two entry points for the workflow -- the second is the workflow itself.
This workflow is an orchestration mechanism that constantly restarts itself, and has some failover mechanisms (e.g. exit on error threshold and soft exit) so that we can manage our queue of durable transactions using WF!
Now, we had this workflow working great when it was all one WF Service because we could call the service, get a response back and send the value of that response back into another entry point in a trigger to issue a soft exit. However, a new requirement has arrisen asking us to make the workflow itself a WF activity in another project and have the Receive/Send-Reply sequences in the WF Service Application project.
However, we need to be able to startup this workflow and forget about it -- then let it know somehow that a soft exit is necessary later on down the road -- but since WF executes on a single thread this has become a bit challenging at best.
Strictly speaking in XAML activities Parallel and ParallelForEach are how you perform asynchrony.
The workflow scheduler only uses a single thread (much like UI) so any activity that is running will typically be running on the same thread, unless it implements AsyncCodeActivity, in which case you are simply handing back the scheduler thread to the runtime while waiting for a callback from whichever async code your AsyncCodeActivity implementation is calling.
Therefore are you sure this is what you want to achieve? Do you mean you want to run it after you have sent your initial response? In this case place your activity after the Send Reply.
Please provide more info if these suggestions don't answer your question./
Update:
The original requirement posed (separating implementation from the service Receive/Send activities) may actually be solved by hosting the target activity as a service. See the following link
http://blog.petegoo.com/index.php/2011/09/02/building-an-enterprise-workflow-system-with-wf4/
I am trying to construct a simple windows workflow to monitor a directory for inbound files and do some DB updates using Windows WF 4.0. Currently I am planning to build a 'WCF Workflow Service' and host it as a 'Windows service' running 24/7 (with a daily service shutdown and startup).
Further in the future I am planning to consume this service using an ASP.NET/WPF application to create a basic dashboard kind of stuff.
Considering the idea of directory polling for files with WF hosted on windows service, does it seems to be a good idea? What can be the cons of this?
Please advice if there are any drawbacks on this or can this achieved by better means?
I'm actually doing this, but it is a bit more complex than you think, and should be avoided if possible.
You should not be blocking from within an Activity; if it is expected to be a long running Activity that is waiting from input from the outside (FileSystemWatcher event, for instance), the workflow should idle itself and wait to be woken from the outside.
How I did this was I created a workflow extension that hosted the FileSystemWatcher. Once the Activity was ready to watch for a file, it created a bookmark and passed it to the extension.
The extension then started the FSW, holding onto the bookmark.
When a FSW event was fired, the extension resumed the bookmark, passing in an object that contained details about the event. The Activity did what was needed with the event, then re-scheduled itself.
Normally I wouldn't have done this, but I had some requirements that forced me to use WF4 to accomplish this goal. If I didn't have to use WF4, I would have just spun up the FSW within the service and consumed the events.
Unless you expect to have to be very flexible with your configuration detailing what you do with the FSW event, and expect this to change relatively often during deployment of the service, I'd skip WF4.
I need to get the next activities(transitions) what my workflow is being blocked for as soon as workflow entered a new state without relying on workflow persistence service, I found out that workflow persistence start to hit database when workflow instance is idle, which has a time latence when there are more than one instance of workflow running, it pose a serious problem for me, I need the blooking bookmarks to be in Synch with my workflow status, which I will set in code activity when workflow enters its new state, from codeActivityContext and NativityContext, there is no way to get the api to get this information(the next transitions), both the statemachine class and state class are sealed, there is not way to tag into it.I am using the blocking bookmarks to indict how the workflow will flow to U.I, so that I can drive the workflow from U.I, I am hosting the statemachine using workflowserviceHost with IIS. I am wondering why I am the only one run into this issue, I have been struggle with this issue for some time.
Thanks in advance.
Your best options is using a TrackingParticipant where you can see exactly what is going on in a workflow as it is executing. From the TrackingParticipant you can then save the bookmarks and have the UI reuse them.
I want each sequence inside a foreach<T> activity running in a different thread. Is this possible by using WWF 4.0? If not, how can I achieve multithreading in WWF 4.0?
It depends on the kind of work you are doing. By default the workflow scheduler will only execute a single activity in a workflow at the time, no way around that. The parallel activities schedule multiple child activities at the same time but they don't execute in parallel.
The big exception to the rule is AsyncCodeActivity type activities. The scheduler will execute another activity as soon as they are doing some asynchronous stuff. Now this works best with IO bound work like database access or network IO but that is not a requirement.
So to achieve true parallelism in your workflows you need to be use a combination of one of the parallel activities with activities deriving from AsyncCodeActivity.
To achieve parallel execution of a foreach, use ParallelForEach.