openstack team mailing list archive

[Kun Huang <Academicgareth@xxxxxxxxx>]

Thanks your explanation, John.

That we can't simply auto create after getting a 404 is the core reason.
At same time, I know why -1 is called "mixed responses" now :)



On Thu, Feb 14, 2013 at 1:26 AM, John Dickinson <me@xxxxxx> wrote:

> This part of the code gets the account info, but if the account isn't
> found and account autocreation is set (eg for tempauth and keystone), then
> we need to create the account first before returning the info.
>
> However, since there are multiple replicas of the account in the cluster,
> we can't simply auto create after getting a 404. Swift is eventually
> consistent and the 404 may be stale data. We don't want to overwrite the
> account with a create if it already exists. So this loop is making sure
> that the account doesn't exist in any of <replica count> nodes, and if
> there is a combination of 404 and errors returned, we don't send another
> account create.
>
> That's a little complicated, so here's some bullets:
>
> Got any successful response (2xx) from a server: return the account info
> Got 404 form all the servers: auto create the account and return the info
> (if the create was successful, else error)
> Got any errors other than 404 or 507 but no success: return error (ie
> return None, None, None)
> Got 507 from a server: skip that server for this an subsequent requests
> (ie error_limit) and carry on
>
> --John
>
>
> On Feb 12, 2013, at 4:11 AM, Kun Huang <Academicgareth@xxxxxxxxx> wrote:
>
> > Hi, Chmouel and Darrell
> >
> > I know you're working on /swift/proxy/controllers/base.py for this bug:
> https://review.openstack.org/#/c/21563/
> > I didn't know the
> https://github.com/openstack/swift/blob/master/swift/proxy/controllers/base.py#L371to #372. Could you show me a simple understanding?
> >
> >
> >
> > elif resp.status == HTTP_NOT_FOUND:
> >
> >
> >
> > if result_code == 0:
> >
> >
> >
> > result_code = HTTP_NOT_FOUND
> >
> >
> >
> > elif result_code != HTTP_NOT_FOUND:
> >
> >
> >
> > result_code = -1
> >
> >
> >
> > In this part, given a 404 response, we should reset the variable
> result_code. If result_code is 0, reset it 404, 404 do nothing, and others
> set -1.
> >
> > What's the case for the "-1"?
> > Furthermore, I simply think resp.status is sufficient condition to set
> result_code, so why these judgement need the result_code value in last loop
> (while attempts_left loop).
> >
> >
> > Gareth
> > _______________________________________________
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