Explanation needed for success and failure link in WFM?

Hi ,

I am new to work modular concept .I have a confusion regarding success , failure links provided in wfm .As

task transition is chosen at script level based on the output of od clt execution ,if based on that value we can determine which task to proceed using default links.Can anyone explain how it can be helpful relating any real time scenario.

Thanks

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Rick Poulin

I have no idea what you're asking, so here's a clarification on those transition types.

Most tasks only understand "default" links because there is no innate "meaning" to them -- that is derived from the context of your implementation. So for user tasks, default links basically offer choices to the user, for which way to proceed along your workflow. For external/cgi/url tasks, they offer a choice for your custom script to transition based on the result of whatever execution it ran.

Some new task types in the modeler DO have innate meaning to them, namely the deploy task. A deploy task is syntactic sugar for an external task with a pre-supplied implementation that already has a strict meaning of "success" versus "failure". These special transition types are also syntactic sugar, as they get converted to normal transitions in the jobspec (plus URL variables to tell the code which is which).

The WFM tool's validation will basically tell you which tasks need default transitions and which ones need success/failure transitions -- these will *always* be mutually exclusive.

To answer what I think was your question -- if based on that value we can determine which task to proceed using default links. The only way to choose a transition is by name (or by its index in an unpredictably-ordered array) so you need to carefully label the transitions coming out of an external task because your custom code for that task will need to be aware of exactly those same labels.

gauravTsDev

yaa, thats what I was trying to understand if we can control task transition via custom script .Whats the point having success or failure links .And deployment task must have atleast success link.N if we take deployment task do we need not control task transition via custom script ?

Rick Poulin

If you're going to be writing your own implementation code for the task, then the only difference between using a deployment task with success/failure links versus a URLExternalTask with default links is that the former makes a picture that is easier to understand for the next person to make changes to the model.

http://en.wikipedia.org/wiki/Syntactic_sugar

nipper

To add to Rick's reply, there is also a timeout link. Use it for any automated task.

This should link to whatever the failure link goes to, or use it as a bypass. There will be times where a task fails to complete for one reason or another, this will move the job along, you have do decide where.

The timeout duration is up to you, I use 1 minute for email tasks, 1 hour for normal java/perl tasks and 4 hours for deployment tasks.

Adam Stoller

To add to @nipper's response - the timeout link can also be used on user and group tasks - usually to transfer to a notification task to remind the owner (or shared-by members) of the task that they didn't complete within a certain amount of time (hours, perhaps days) - in such cases, the notification task should transition back to the original task that timed out, thereby restaring the clock until the task gets completed or times out again.

nipper

ghoti wrote:
To add to @nipper's response - the timeout link can also be used on user and group tasks - usually to transfer to a notification task to remind the owner (or shared-by members) of the task that they didn't complete within a certain amount of time (hours, perhaps days) - in such cases, the notification task should transition back to the original task that timed out, thereby restaring the clock until the task gets completed or times out again.

Yea but one interesting, pain-in-the-a$$ feature is that the timeout doesn't start for a group task until the group task has been taken.

So if it remains waiting for a reviewer to start, there is no way to time that out.

gauravTsDev

Thanks ghoti ,nipper,rpoulin ..this information definitely help my understanding.