I'd like to subscribe to exceptions, while leaving existing code in place to handle all other cases. XSLT applies tests in order of complexity. Is the behavior of subscriptions that 'conflict' defined?
It should be possible using service windows, but I'd like a more robust solution.
No, there is no order that subscriptions are applied in BizTalk, nor is there a conflict in subscriptions. If more than one subscription matches the message, both will get the message and process it.
If you don't want the existing subscription to process those messages, you need to add a AND {propertyname} <> {value} to the existing subscription.
Related
In below scenario, what would be the bahavior of Axon -
Command Bus recieved the command
It creates an event
However messaging infra is down (say kafka)
Does Axon has re-queing capability for event or any other alternative to handle this scenario.
If you're using Axon, you know it differentiates between Command, Event and Query messages. I'd suggest to be specific in your question which message type you want to retry.
However, I am going to make the assumption it's about events, as your stating Kafka.
If this is the case, I'd highly recommend reading the reference guide on the matter, as it states how you can uncouple Kafka publication from actual event storage in Axon.
Simply put, use a TrackingEventProcessor as the means to publish events on Kafka, as this will ensure a dedicate thread is used for publication instead of the same thread storing the event. Added, the TrackingEventProcessor can be replayed, thus "re-process" events.
Is it possible using Rebus to set priority on messages?
The scenario is that we have a queueworker singing documents, for different services, some of them witch the user awaits the result, and some that the signed document is just stored for later use.
It would then be nice to prioritize the messages of the users that awaits a response. Is this possible ?
We are using Rebus2 with Azure ServiceBus
Unfortunately, since Azure Service Bus does not natively support message prioritization, and implementing it with the priority queue pattern would be cumbersome, it cannot readily be done by setting a priority on a message.
A simple approach that works in the general case is to have separate Rebus instances for different priorities, where one particular instance could then be used to "fast-track" messages that need to overtake all the other messages.
The instances could have the exact same configuration, except they use different input queues. This way, the routing configuration (endpoint mappings) get to determine which priority a message gets.
I am currently writing an orchestration that is directly bound to the message box, picks up messages and filters according to the filter expression in the receive shape inside said orchestration. The problem I'm having is this; I want to be able to change the filter in the BizTalk bindings, just like send filters are changed in the bindings. Really, I just don't want to have to recompile and re deploy every time My filter changes. Is there a way to do this? I'm thinking maybe modify the binding.xml file somehow, or possibly try a custom pipeline with configurable properties(as my last resort).
If it matters I typically use the BizTalk Deployment Framework for deployments.
No, it is not possible to modify a Receive Shape Filter at Runtime.
If the filter needs to be dynamic, then you will have to apply that logic upstream. The idea of using a custom Pipeline Component is a common solution.
One other approach to consider is leaving you Receive Shape Filter broad and testing each incoming message with the BRE. If it 'passes', continue processing, otherwise exit. BRE Policies/Rules can be updated at runtime.
For this sort of thing you will probably want to execute Business Rules in the Receive Pipeline that then sets a context property on the message that then determines the routing.
That way the filter in the Orchestration is lightweight and doesn't need to be changed.
See http://brepipelineframework.codeplex.com/ (Disclosure: This is written by a colleague of mine)
I've been working under the assumption that a message entering an orchestration was validated against the messages schema, only to realize recently that this is not the case. There doesn't appear to be a validate shape, so I'm wondering if there is a clean reusable pattern out there to implement this?
You can validate the messages on an XMLReceive pipeline, but unfortunately this requires specifying the DocumentSpecNames which can detract from the flexibility of the receive.
A workaround is to use a custom "ValidatingXmlPipeline" and add the XMLValidator pipeline component to it.
As per your original question, there is a config setting in btsntsvc.config under Debugging called ValidateSchemas when message variables are assigned. I can't say I've used this as it will probably impact performance.
I have created a simple order manager wf service (state machine) in WF4.
Order (EF entity) properties: Id, IsExport, NumOfProduct, ProductName, Status (waiting, approved, rejected).
State machine states:
1. OrderReceived (validation -> response activity)
2. Waiting (empty)
- Transitions:
update(update order activity) -> waiting state
approve(assign status field, update order and response activities) -> final state
3. Final state.
Correlation key: Order.Id
The implementation rised a few questions.
WF can manage one flow of the order instance, the order flow and the order entity is in one-one relation.
Question is that where and how should I implement the listing of entityes according to a state filter (eg. approved orders or waiting orders). The list should be accessible via WCF service method.
What is the best practise to manage the batch data processing. (eg: Multiple order approval. "Foreach" in the client is not the required sln.)
The state of the order is symbolized by the "state activity persisted instances" and the entity's status field in the db as well.
What is the best practise to decide the state of the entity, listing the active persisted activity instances in the defined state or select the entities from the db (by an activity) according to a state filter parameter?
Any help would be appreciated.
Good questions!
Taking your first and third questions, there are several possible approaches to this. All require that you write a custom WCF service to enumerate the required orders. This would probably not be a WF service; it might be a REST or OData service. How would you implement the service?
You could do it entirely by querying your database through EF. This would have no dependency on WF at all, and is probably the easiest way. Your workflow would update the database record on each state change, and the service would only need to read that value.
You could rely on the tracking mechanism provided by WF, and the extensions that Ron Jacobs refers to in his answer to your question. The tracking infrastructure is described here on MSDN. It is possible to use the tracking object in memory to get the state of active workflows. However, this probably won't work well with IIS/WF services, which are automatically persisted and unloaded when dormant. You would be better off using the tracking facilities to write state records to a database. Your custom service would then just query this tracking database.
Unless you want comprehensive information about the state changes and updates that have occurred through your WF service, suggestion number one should suffice.
As for your second question, that is a little more complicated. Let's say you write a REST service that lists the orders awaiting approval. You write a Web page that displays those orders, and the user can check the orders he wants to approve. Now, the number of workflows that you need to update is the same as the number of orders he approves.
You could, as you mention, call the Web service multiple times—but for a large number of orders that would be an unnecessary overhead.
What's the alternative? You would need to write a custom service method on your non-WF service that takes an array of order ids. That service would have to call your WF service multiple times to update each one. Since the WF service is being called from another service on the same machine, you can use the .Net Named Pipe binding instead of one of the HTTP bindings so that the overhead is much less.
It's worth noting that Entity Framework doesn't support batched updates either. You'd need to write a stored procedure or custom SQL if you wanted the database update to be batched too.
Is all of this worth the effort? Probably! Using WCF and the named pipes binding is pretty standard with WF. You'll need to configure Windows Activation Service for named pipes. Also, if you're not already using AppFabric for Windows Server, have a look into it, because it adds some very good management tools for WF services.
I recently published some new samples to show how you can access the current state of the StateMachine and possible transitions. These might help you.
Windows Workflow Foundation (WF4) - Tracking State Machine Workflow Service
Windows Workflow Foundation (WF4) - Tracking State Machine