[openstack-dev] [Mistral] For-each

Dmitri Zimine dzimine at stackstorm.com
Thu Dec 18 23:39:30 UTC 2014

Based on the feedback so far, I updated the document and added some more details from the comments and discussions. 

We still think for-each as a keyword confuses people by setting up some behavior expectations (e.g., it will run sequentially, you can work with data inside the loop, you can ‘nest’ for-each loops - while it’s not a loop at all, just a way to run actions which are not accepting arrays of data, with arrays of data). 

But no better idea on the keyword just yet. 


On Dec 15, 2014, at 10:53 PM, Renat Akhmerov <rakhmerov at mirantis.com> wrote:

> Thanks Nikolay,
> I also left my comments and tend to like Alt2 better than others. Agree with Dmitri that “all-permutations” thing can be just a different construct in the language and “concurrency” should be rather a policy than a property of “for-each” because it doesn’t have any impact on workflow logic itself, it only influence the way how engine runs a task. So again, policies are engine capabilities, not workflow ones.
> One tricky question that’s still in the air is how to deal with publishing. I mean in terms of requirements it’s pretty clear: we need to apply “publish” once after all iterations and be able to access an array of iteration results as $. But technically, it may be a problem to implement such behavior, need to think about it more.
> Renat Akhmerov
> @ Mirantis Inc.
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