I am using a send task to which the following Javadelegate class is attached.
public class SendTaskDelegate implements JavaDelegate {
public void execute(DelegateExecution execution) throws Exception {
execution.getProcessEngineServices()
.getRuntimeService()
.createMessageCorrelation("someMessage")
.processInstanceBusinessKey("someBusinessKey")
.correlate();
}
}
But I am getting this error::
An error happend while submitting the task form : Cannot submit task form c0e85bad-719f-11e5-94aa-d897baecf24a: Cannot correlate message someMessage: No process definition or execution matches the parameters
How can I debug it?
The error message says, that your JavaDelegate code just gets excuted correctly. The process engine tries to find a running process instance with 'someBusinessKey' as business key and currently waiting for a message 'someMessage', but does not find such an instance. Your code acts as if there were such an instance and you try to find it and tell it about a message. See the docs section about correlation methods - in principle the mechanism is used to 'route' a message to the correct instance targeting it.
As a sidenote: your JavaDelegate seems to get called in the same transaction with which you also try to complete a task. The "borders of transactions" in your process can be managed with 'async' attributes described in the docs section about transactions in processes.
Related
We are facing an MismatchingMessageCorrelationException for the receive task in some cases (less than 5%)
The call back to notify receive task is done by :
protected void respondToCallWorker(
#NonNull final String correlationId,
final CallWorkerResultKeys result,
#Nullable final Map<String, Object> variables
) {
try {
runtimeService.createMessageCorrelation("callWorkerConsumer")
.processInstanceId(correlationId)
.setVariables(variables)
.setVariable("callStatus", result.toString())
.correlateWithResult();
} catch(Exception e) {
e.printStackTrace();
}
}
When i check the logs : i found that the query executed is this one :
select distinct RES.* from ACT_RU_EXECUTION RES
inner join ACT_RE_PROCDEF P on RES.PROC_DEF_ID_ = P.ID_
WHERE RES.PROC_INST_ID_ = 'b2362197-3bea-11eb-a150-9e4bf0efd6d0' and RES.SUSPENSION_STATE_ = '1'
and exists (select ID_ from ACT_RU_EVENT_SUBSCR EVT
where EVT.EXECUTION_ID_ = RES.ID_ and EVT.EVENT_TYPE_ = 'message'
and EVT.EVENT_NAME_ = 'callWorkerConsumer' )
Some times, When i look for the instance of the process in the database i found it waiting in the receive task
SELECT DISTINCT * FROM ACT_RU_EXECUTION RES
WHERE id_ = 'b2362197-3bea-11eb-a150-9e4bf0efd6d0'
However, when i check the subscription event, it's not yet created in the database
select ID_ from ACT_RU_EVENT_SUBSCR EVT
where EVT.EXECUTION_ID_ = 'b2362197-3bea-11eb-a150-9e4bf0efd6d0'
and EVT.EVENT_TYPE_ = 'message'
and EVT.EVENT_NAME_ = 'callWorkerConsumer'
I think that the solution is to save the "receive task" before getting the response for respondToCallWorker, but sadly i can't figure it out.
I tried "asynch before" callWorker and "Message consumer" but it did not work,
I also tried camunda.bpm.database.jdbc-batch-processing=false and got the same results,
I tried also parallel branches but i get OptimisticLocak exception and MismatchingMessageCorrelationException
Maybe i am doing it wrong
Thanks for your help
This is an interesting problem. As you already found out, the error happens, when you try to correlate the result from the "worker" before the main process ended its transaction, thus there is no message subscription registered at the time you correlate.
This problem in process orchestration is described and analyzed in this blog post, which is definitely worth reading.
Taken from that post, here is a design that should solve the issue:
You make message send and receive parallel and put an async before the send task.
By doing so, the async continuation job for the send event and the message subscription are written in the same transaction, so when the async message send executes, you already have the subscription waiting.
Although this should work and solve the issue on BPMN model level, it might be worth to consider options that do not require remodeling the process.
First, instead of calling the worker directly from your delegate, you could (assuming you are on spring boot) publish a "CallWorkerCommand" (simple pojo) and use a TransactionalEventLister on a spring bean to execute the actual call. By doing so, you first will finish the BPMN process by subscribing to the message and afterwards, spring will execute your worker call.
Second: you could use a retry mechanism like resilience4j around your correlate message call, so in the rare cases where the result comes to quickly, you fail and retry a second later.
Another solution I could think of, since you seem to be using an "external worker" pattern here, is to use an external-task-service task directly, so the send/receive synchronization gets solved by the Camunda external worker API.
So many options to choose from. I would possibly prefer the external task, followed by the transactionalEventListener, but that is a matter of personal preference.
I am using a ServiceBusTrigger to execute code when receiving a message. I would like to use the Singleton attribute to limit which messages can be executed in parallel. This attribute allows specifying a scope bound to properties on the incoming message, such that messages with different values can be executed in parallel but ones with the same value must be done serially.
This works when using top level properties on the incoming message object like CorrelationId.
Example
[Singleton("{CorrelationId}", SingletonScope.Function, Mode = SingletonMode.Function)]
public async Task HandleMessage(
[ServiceBusTrigger("my-topic-name", "my-subscription-name"), ServiceBusAccount("my-account-name")]
Message message,
CancellationToken cancellationToken
)
{
await Task.Yield();
}
What I am struggling to figure out is how to achieve the same behavior with user properties on the message. These are stored in the UserProperties dictionary on the Message object. I'm not seeing a way to refer to these with the binding statement in the Singleton attribute, but it seems like this would be a very common use case when combining Singleton with ServiceBusTrigger
The Service Bus Bindings exposes Message Metadata in binding expressions. So, userProperties.<key> should do the trick.
I'm trying to set a process variable in Task Listener of a human-task using Groovy script during 'create' as event type in Camunda BPMN work-flow.
execution.setVariable('newUserType',"RMAOFF1");
But it is giving me error saying "The task does not exist or the corresponding process instance could not be resumed successfully."
Any help most appreciated.
In a Task Listener you don't have an execution (DelegateExecution).
But you have a task (DelegateTask delegateTask).
So your example is: task.setVariable('newUserType',"RMAOFF1")
By the way this would also work in an expression ${task.setVariable('newUserType',"RMAOFF1")}
For more infos see https://docs.camunda.org/manual/7.18/user-guide/process-applications/process-application-event-listeners/
The signature of a TaskListener is void notify(DelegateTask task). I guess you are accidentally using an ExceutionListener, but that does not have a "create" event.
I need to make custom validation of instance before saving it to MySQL DB.
So I perform (async) check inside beforeValidate model hook.
MyModel.beforeValidate = function(next){
// async check that finally calls next() or next(new Error('fail'))
}
But when check fails and I pass Error obj to next function, the execution continues anyway.
Is there any way to stop execution and response to client with error?
This is a known bug in the framework, see https://github.com/strongloop/loopback/issues/614
I am working on a new hook implementation that will not have issues like the one you have experienced, see loopback-datasource-juggler#367 and the pull request loopback-datasource-juggler#403
I have a MVC app where I am trying to capture all the incoming requests in a ActionFilter. Here is the logging code. I am trying to log in a fire and forget model.
My issue is if I execute this code synchronously by taking out the Task.Run Elmah does send out an email. But for the code shown below I can see the error getting logged to the InMemory logger in elmah.axd but no emails.
public void Log(HttpContextBase context)
{
Task.Run(() =>
{
try
{
throw new NotImplementedException(); //simulating an error condition
using (var s = _documentStore.OpenSession())
{
s.Store(GetDataToLog(context));
s.SaveChanges();
}
}
catch (Exception ex)
{
ErrorSignal.FromCurrentContext().Raise(ex);
}
});
}
Got this answer from Atif Aziz (ELMAH Lead contributor) on the ELMAH google group:
When you use Task.Run, the HttpContext is not transferred to the thread pool thread on which your action will execute. When ErrorSignal.FromCurrentContext is called from within your action, my guess is that it's probably failing with another exception because there is no current context. That exception is lying with the Task. If you're on .NET 4, you're lucky because you'll see the ASP.NET app crash eventually (but possibly much after the fact) when the GC will kick in and collect the Task and its exception will go “unobserved”. If you're on .NET 4.5, the policy has been changed and the exception will simply get lost. Either way, your observation will be that mailing is not working. In fact, logging won't work either unless you use Elmah.ErrorLog.GetDefault(null).Log(new Error(ex)), where a null context is allowed. But that call only logs the error but does not do any mailing. ELMAH's modules are connected to the ASP.NET context. If you detach from that context by forking to another thread, then you cannot rely on ELMAH's modules. You can only use Elmah.ErrorLog.GetDefault(null).Log(new Error(ex)) reliably to log an error.