On 01/12/2016 08:24 AM, Dan Prince wrote:
On Tue, 2016-01-12 at 12:52 +0100, Jiri Tomasek wrote:
On 01/11/2016 04:51 PM, Dan Prince wrote:
Background info:
[snip]
In similar manner, is Mistral able to provide a way to get workflow
in
progress data? E.g. We have a Mistral workflow for nodes
introspection.
This workflow contains several actions calling to ironic and
ironic-inspector apis. GUI calls Mistral API to trigger the workflow
and
now it needs to have a way to track the progress of that workflow.
How
would this be achieved?
I've been running 'mistral execution-list' and then you can watch
(poll) for the relevant execution items to finish running. Sure,
polling isn't great but I'd say lets start with this perhaps.
I think forcing GUI to poll the APIs that are
called in the actions and try to implement logic that estimates what
state the workflow is to report about it is not a valid solution. We
need the workflow API (Mistral) to provide a lets say web sockets
connection and push the status of actions along with relevant data,
so
GUI can listen to those.
I don't think Mistral has a websockets implementation. I think Zaqar
does though, and I think perhaps one way we could go about this sort of
notification might be to integrate our workflows with a Zaqar queue or
something. GUI would listen to a Zaqar queue for example... and the
workflow (as it executes) would post things to a specific queue.
Perhaps this is opt-in, only if a Zaqar queue is provided to a given
workflow. FWIW, integrating Mistral w/ Zaqar actions would likely be
quite easy.
Heat currently has a similar system for stack actions. The user provides
a zaqar queue in the environment file, and every resource action
generates a notification on that queue. I think a similar system would
work for Mistral jobs.
For "domain-specific" notifications like receiving a notification for
certain discovery stages, the TripleO custom actions could also publish
messages to a queue so users get something more granular than "this
Mistral job finished."
Alternately we could look at what it would take to add websocket
support to Mistral directly.
I really don't think adding websockets to Mistral would be worth it -
Zaqar is a much better solution for notifications since it already has
websocket, webhook, and even email (yes, that's right) notification options.
I am about to implement your nodes workflow in the GUI to test how it
works.
Jirka
--
Ryan Brown / Senior Software Engineer, Openstack / Red Hat, Inc.
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