asynchronous urlexternal task design pattern

catorarn

I am using 731.

i have this use case:
a workflow has a java (URL) external task which calls a service asynchronously. The service follows a JMS pattern and publishes status. We need to get a callback to the URL external task in case the job on the service fails or ends. we do not want polling.

Does anyone have experience to share on this? How would the external task be best designed

Adam Stoller

I am using 731. i have this use case: a workflow has a java (URL) external task which calls a service asynchronously. The service follows a JMS pattern and publishes status. We need to get a callback to the URL external task in case the job on the service fails or ends. we do not want polling. Does anyone have experience to share on this? How would the external task be best designed

Off the top - the fact that the script runs asynchronously is going to be the primary source of the problem (obviously?)
If you can pass information to this script (like the taskid) and have this script when completed invoke (directly or indirectly) an iwcallback on the task (CLT, Perl, or CSSDK) - that should allow your task to sit there until the actual script is done and then proceed.

If you have both a success and failure transition, make sure your script invokes the iwcallback for the proper transition.

If you're trying to have your workflow proceed without waiting for the script to finish, a simple timeout on the task to transition it to the next task should suffice.