Re: [Libguestfs] [PATCH nbdkit] New filter: request-request

On Fri, Oct 15, 2021 at 12:18:27PM +0200, Laszlo Ersek wrote: > On 10/14/21 23:28, Richard W.M. Jones wrote: > > On Thu, Oct 14, 2021 at 04:22:27PM -0500, Eric Blake wrote: > >> I know this is just an RFC, but the idea looks like it may have merit. > >> Would we want to merge this functionality into the 'retry' filter (a > >> single filter, with a knob on whether to retry single requests > >> vs. full connection), or would that be too heavyweight for one filter? > > > > I did look at that, but the current retry filter is complicated enough > > and this would make it quite a lot more complicated (unless you can > > see some easy way to do it). > > > > Also the two filters do have somewhat different behaviour and perhaps > > use cases. > > > > I really need a way to test this with the curl plugin to check that it > > really does what I think it does. In particular I'm not convinced > > curl will actually go through the whole redirect phase in this case, > > which would mean it doesn't actually solve Alexander's problem. > > I wonder if one of the commonly used proxies (squid perhaps?) can be > configured to inject errors / fail requests intentionally with some > user-specified frequency. See other reply - I did check that curl does the right thing here. However I do need to write a standalone test for this. nbdkit carries its own mini webserver for testing the curl plugin: https://gitlab.com/nbdkit/nbdkit/-/blob/master/tests/web-server.c It was only needed because the logical choice for testing -- Python's built-in "python -m SimpleHTTPServer" -- doesn't support byte ranges. Ideally we'd not be extending this any further, but would use an existing single file webserver which supports byte ranges and redirects and has a BSD-like license. https://www.gnu.org/software/libmicrohttpd/ has the wrong license but links to several other interesting projects. Rich.

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