Re: [Engine-devel] Managing async tasks

----- Original Message ----- > From: "Adam Litke" <agl(a)us.ibm.com&gt; To: vdsm-devel(a)lists.fedorahosted.org > Cc: "Dan Kenigsberg" <danken(a)redhat.com&gt;, "Ayal Baron" <abaron(a)redhat.com&gt;, > "Saggi Mizrahi" <smizrahi(a)redhat.com&gt;, "Federico Simoncelli" > <fsimonce(a)redhat.com&gt;, engine-devel(a)ovirt.org Sent: Monday, December 17, > 2012 12:00:49 PM Subject: Managing async tasks > > On today's vdsm call we had a lively discussion around how asynchronous > operations should be handled in the future. In an effort to include more > people in the discussion and to better capture the resulting conversation I > would like to continue that discussion here on the mailing list. > > A lot of ideas were thrown around about how 'tasks' should be handled in the > future. There are a lot of ways that it can be done. To determine how we > should implement it, it's probably best if we start with a set of > requirements. If we can first agree on these, it should be easy to find a > solution that meets them. I'll take a stab at identifying a first set of > POSSIBLE requirements: > > - Standardized method for determining the result of an operation > > This is a big one for me because it directly affects the consumability of > the API. If each verb has different semantics for discovering whether it > has completed successfully, then the API will be nearly impossible to use > easily. Since there is no way to assure if of some tasks completed successfully or failed, especially around the murky waters of storage, I say this requirement should be removed. At least not in the context of a task.

> > > Sorry. That's my list :) Hopefully others will be willing to add other > requirements for consideration. > > From my understanding, task recovery (stop, abort, rollback, etc) will not > be generally supported and should not be a requirement. >