Open Stack

On Mon, Jan 12, 2015 at 10:17 PM, Konstantin Danilov <kdanilov at mirantis.com>
wrote:

> Boris,
>
> Move from sync http to something like websocket requires a lot of work and
> not directly connected
> with API issue. When openstack api servers begin to support
> websockets - it would be easy to change implementation of monitoring
> thread without breaking compatibility.
> At the moment periodical pooling from additional thread looks reasonable
> for me
> and it creates same amount of http requests as all current implementation.
>
> BP is not about improving performance,
> but about providing convenient and common API to handle background tasks.
>
> > So we won't need to retrieve 100500 times information about object.
> As I sad before - this API creates same amount of load as any code which
> we use to check background task currently.
> It even can decrease load due to requests aggregation in some cases (but
> there a points to discuss).
>
> > As well this pattern doesn't look great.
> > I would prefer to see something like:
> > vm = novaclient.servers.create(...., sync=True)
>
> This is completely different pattern. It is blocking call, which don't
> allows you to start two(or more) background tasks
> and from same thread and make some calculations while they running in
> background.
>

Except if you use threads (eventlet or other) - I am still struggling to
enjoy Futures/yield based flowcontrol, lost battle i guess:(.


>
>
>
>
>
> On Mon, Jan 12, 2015 at 1:42 PM, Boris Pavlovic <bpavlovic at mirantis.com>
> wrote:
>
>> Konstantin,
>>
>>
>> I believe it's better to work on server side, and use some modern
>> approach like web sockets for async operations. So we won't need to
>> retrieve 100500 times information about object. And then use this feature
>> in clients.
>>
>>  create_future = novaclient.servers.create_async(....)
>>>     .....
>>>     vm = create_future.result()
>>
>>
>> As well this pattern doesn't look great.
>>
>> I would prefer to see something like:
>>
>>   vm = novaclient.servers.create(...., sync=True)
>>
>>
>> Best regards,
>> Boris Pavlovic
>>
>>
>>
>>
>>
>> On Mon, Jan 12, 2015 at 2:30 PM, Konstantin Danilov <
>> kdanilov at mirantis.com> wrote:
>>
>>> Hi all.
>>>
>>> There a set of openstack api functions which starts background actions
>>> and return preliminary results - like 'novaclient.create'. Those
>>> functions
>>> requires periodically check results and handle timeouts/errors
>>> (and often cleanup + restart help to fix an error).
>>>
>>> Check/retry/cleanup code duplicated over a lot of core projects.
>>> As examples - heat, tempest, rally, etc and definitely in many
>>> third-party scripts.
>>>
>>
We have some very similar code at the moment, but we are keen to move away
from it to
something like making use of rpc ".{start,end}" notifications to reduce the
load we put on keystone and
friends.


>
>>> I propose to provide common higth-level API for such functions, which
>>> uses
>>> 'futures' (http://en.wikipedia.org/wiki/Futures_and_promises) as a way
>>> to
>>> present background task.
>>>
>>> Idea is to add to each background-task-starter function a complimentary
>>> call,
>>> that returns 'future' object. E.g.
>>>
>>>     create_future = novaclient.servers.create_async(....)
>>>     .....
>>>     vm = create_future.result()
>>>
>>
Is that going to return on any state change or do you pass in a list of
acceptable states?

-Angus


>
>>> This allows to unify(and optimize) monitoring cycles, retries, etc.
>>> Please found complete BP at
>>> https://github.com/koder-ua/os_api/blob/master/README.md
>>>
>>> Thanks
>>> --
>>> Kostiantyn Danilov aka koder <http://koder.ua>
>>> Principal software engineer, Mirantis
>>>
>>> skype:koder.ua
>>> http://koder-ua.blogspot.com/
>>> http://mirantis.com
>>>
>>>
>>> __________________________________________________________________________
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>>>
>>
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>>
>
>
> --
> Kostiantyn Danilov aka koder.ua
> Principal software engineer, Mirantis
>
> skype:koder.ua
> http://koder-ua.blogspot.com/
> http://mirantis.com
>
> __________________________________________________________________________
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