topic Re: Exception Handling of Asynchronous Processes in Alfresco Archive

Exception Handling of Asynchronous Processes

flavio_donze — Fri, 12 Apr 2013 11:51:37 GMT

HelloAfter the discussion here http://forums.activiti.org/en/viewtopic.php?f=6&t=6334 about transaction deadlocks, I ended up setting my callActivity activiti:async="true". This solved my deadlock problem, but now I'm facing the problem of handling exceptions.The workflow that caused the deadloc

Re: Exception Handling of Asynchronous Processes

jbarrez — Mon, 15 Apr 2013 10:01:57 GMT

The problem is that you don't really know when the execution will actually happen.
If the load is high, it might even take a while before it is picked up by the job executor.

I think you need to ask yourself what would be the wanted behavior:
- Do you want to show it in the UI directly? If so, we will have to dig deeper in why the deadlock happens
- Is email sending enough?
- Do you want to create a dedicated UI for failed processes?

Also now I get three mails, since the job executor tries three times to execute the workflow.
Is it possible to disable this behaviour?

Yes: by default there is a retry interceptor configured when you execute any API call (and thus a Command).
You can remove this interceptor, change or tweak it. Or add your own.

Similarly you could add your own interceptor that does something with the exception that happens during process execution.
That way you can catch it (even when its done async) and do something accordingly.

Re: Exception Handling of Asynchronous Processes

flavio_donze — Wed, 17 Apr 2013 07:13:18 GMT

Hi jbarrez

Thanks for your reply!

If we could get rid of the deadlock, showing the exception in the UI would be a good option. This is how I have it right now.
I have added a test case in the deadlock thread: http://forums.activiti.org/en/viewtopic.php?f=6&t=6334&p=23640
Otherwise sending an email is an ok solution.

I looked into the retry interceptor and found these two classes org.activiti.engine.impl.interceptor.RetryInterceptor and org.activiti.engine.impl.interceptor.JtaRetryInterceptor.
I did set breakpoints all over those classes but I never enter it, I also did not find any other place where this handling could be done.
Could you point me to the right class?
Is there some documentation about this?

greets and thanks for your help
Flavio

Re: Exception Handling of Asynchronous Processes

jbarrez — Thu, 18 Apr 2013 11:07:43 GMT

<i>Could you point me to the right class?</i>

I checked and you are indeed right. The retry interceptor is not set by default.
But I then remembered it has to do with jobs: jobs have a retries fields that is decreased when a job execution fails.

<i>Is there some documentation about this?</i>

No, I'm sorry. That stuff could indeed use docs. I put it on my todo list.

Re: Exception Handling of Asynchronous Processes

flavio_donze — Mon, 22 Apr 2013 09:22:31 GMT

I came across http://jira.codehaus.org/browse/ACT-1046, I think the FailedJobCommandFactory is what I was looking for.

I will have a look at it and report back.

Re: Exception Handling of Asynchronous Processes

flavio_donze — Tue, 23 Apr 2013 06:17:45 GMT

I wrote a blog about the exception handling: http://flaviodonze.blogspot.ch/2013/04/activiti-overall-exception-handlingin.html

Re: Exception Handling of Asynchronous Processes

frederikherema1 — Wed, 24 Apr 2013 07:34:50 GMT

Thanks for sharing your experiences!