5:04 a.m.
On 7/2/2014 11:06 PM, Sheldon wrote:
On 06/27/2014 07:15 PM, Wen Wang wrote:
> Dear all,
> *
> **Problems:*
> Now our strategy for long time operation is using task which the
> browser needs to check up-to-date task status time by time until the
> task ends. It's time consuming and less efficient. Also there exists
> several problems when locating each task when doing debug generating
> and storage pool as well as some new features that might use task
> strategy in the future.
>
> *Solution*:
> As talked with Sheldon and Zhengsheng, we came up with a solution
> that avoid browser checking status every 200ms. Also, we might need
> some more labels in each task to provide more information when
> getting the task like we might need to indicate which operation
> triggered certain task. What's in our mind is to use the strategy
> that allow the server inform browser about the task information. Our
> proposal is designed as follows.
>
> 1) Browser needs to register to the back end to indicate which part
> the result needs to reply to when the task finished.
> 2) The back end use broker to manage message distribution: when a
> task is finished or experiencing an error, back end inform the
> browser certain part of work is finished or error.
> 3) Using websocket of cherrypy to accomplish the message transfer.
Now let me elaborate above.
For Browser, it can be an event loop worker.
It can subscribe event message that users care to the back end broker.
listen the events from the broker and take some action for the event.
For back:
The broker should collect and store the events from everywhere.
The broker should dispatch the message to the client who subscribes it.
For some event, broker should determined whether it should dispatch to
user.
Such a VM shutdown event, the broker just send it to the user who has
the access permission. (Yu Xing's suggestion)
We had better define the event message format.
We had better to find an existing python lib for it. If no we should
code it for ourself.
[ client1 ]
care VM | ^
libvirt event -------------\ shutdown | | VM shutdown
\ V |
event 1 -------- -------------------------->[ broker ]
/ ^ |
dispatch
event 2 ------------/ | |
subscribe | V listen
[ client2 ]
For websocket:
There's also an issue about it.
https://github.com/kimchi-project/kimchi/issues/22
The websocket is the pipe to connect the broker of the UI event worker.
We should support websocket proxying directly from the cherrypy server
on its given port.
Zheng Sheng is working on it. It can work on cherrypy. Seems
something wrong with nginx.
Thanks Sheldon, as we discussed yesterday on scrum meeting, it's better
to use the socket method solve long time task problem. We wanted to make
this feature a generic one so that every long-time task will benefit
from it. I think Kimchi should use the user information alongside with
task type to decide which user(s) we should send the message to. It all
happen when automatically. I don't think we need the message management
for users.
Also, do we need to change all the tasks to this socket pattern or just
for long-time tasks? I recommend long-time tasks.
For the message format, I think we might need the user name, role and
the url to indicate which kind of task we are running.
As you said , the broker filter the message from the backend and I might
need to know your design for the message frontend gets. We need to have
it discussed further more.
>
> Best Regards
>
> Wang Wen
>
>
>
>
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--
Thanks and best regards!
Sheldon Feng(???)<shaohef(a)linux.vnet.ibm.com>
IBM Linux Technology Center