Sequence of event tasks

Question

Hi All,
I defined 2 different tasks on change and modify event of the attribute MXREF_MX_PRIVILEGE to change the group assignments in Active directory.
When I change the value of MXREF_MX_PRIVILEGE from  "<mskeyvalue_priv1>|<mskeyvalue_priv4>" to "<mskeyvalue_priv1>|<mskeyvalue_priv2>|<mskeyvalue_priv3>", sometimes priv1 is assigned in AD and sometimes not, because the adding event is finished before the delete event.
How do I know the deleting event for priv1 is finished before the modify event?
thanks,
Joachim

Answer 1

Hi Joachim,
I read your question again. I think there is a way to prevent one job to start before another has finished.
Did I get you right that you first handle the add event for
<mskeyvalue_priv1>|<mskeyvalue_priv4>
and then the modify event for
<mskeyvalue_priv1>|<mskeyvalue_priv2>|<mskeyvalue_priv3>
sometimes the delete handler finishes faster than the add handler?
If so, then I can perhaps answer the question. What you can do is to check in table mxp_provision whether an instance of the event handler is still running. Let's say the event handler is an ordered task group with id 100 and the mskey of the person is 200 then the statement to check whether something is currently being processed is:
select count(mskey) from mxp_provision where mskey=200 and parentid=100
If the result is 0 then nothing is in the queue.
Another question is how you make the other operations wait. Here I have 2 approaches, one is simple, one is complex:
1) you code the query above in a conditional task and if result is >0 then you wait some minutes and try again then. If it doesn't succeed after several retries then make the entire thing fail.
2) You make the event handler run into an approval task. This way the execution is stopped until the approval is approved. This is a kind of semaphore mechanism: If somebody else has the lock then I wait until the lock is released. The lock holder must run a query when done in order to determine which other tasks are waiting in an approval and approve the one which waits the longest. All this can be done with a little scripting. But I wouldn't like to implement this, it's a pretty tedious.
Cheers,
Kai
http://kaidentity.blogspot.com/