Re: [PATCH v2 3/3] http: automatically retry some requests

From: Sean McAllister <smcallis@google.com>
Date: Oct 14, 2020, 22:38 UTC
Message-ID: <CAM4o00eZjr2apH6WO-sTvuOfR-cuiSh1yhh3j=14ZFstXDz7bA@mail.gmail.com>
In-Reply-To: <20201014193456.GA365553@coredump.intra.peff.net>

Some large projects (Android, Chrome), use git with a distributed backend to feed changes to automated builders and such. We can actually get into a case where DDOS mitigation kicks in and 429s start going out. In that case I think it's pretty important that we honor the Retry-After field so we're good citizens and whoever's running the backend service has some options for traffic shaping to manage load. In general you're right it doesn't matter _that_ much but in at least the specific case I have in my head, it does.

On Wed, Oct 14, 2020 at 1:34 PM Jeff King <peff@peff.net> wrote:

Show 25 quoted lines

>
> On Wed, Oct 14, 2020 at 01:10:46PM -0600, Sean McAllister wrote:
>
> > On Wed, Oct 14, 2020 at 1:09 PM Sean McAllister <smcallis@google.com> wrote:
> > >
> > > On Tue, Oct 13, 2020 at 3:14 PM Jeff King <peff@peff.net> wrote:
> > > >
> > > > I do think you could be leveraging CURLINFO_RETRY_AFTER rather than
> > > > implementing your own header parsing, though.
> > > >
> > > Ah I didn't know about CURLINFO_RETRY_AFTER, I'll look at that and use
> > > it if I can.
> > >
> > I took a look, it looks like CURLINFO_RETRY_AFTER was only added in
> > 7.66 (September, 2019),  so
> > I don't think it's reasonable to rely on it for getting the
> > Retry-After value in this case.
>
> I agree that's pretty recent.
>
> How important is it that we respect it? I.e., we'd have some sane retry
> behavior if the header is missing anyway. On older curl versions, how
> bad would it be to just use that fallback behavior all the time?
>
> -Peff