Re: RFC: Resumable clone based on hybrid "smart" and "dumb" HTTP

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

> Clients do not have to _just_ fetch a packfile. They could get a bundle
> file that contains the roots along with the packfile. I know that one of
> your goals is not duplicating the storage of the packfile on the server,
> but it would not be hard for the server to store the packfile and the
> bundle header separately, and concatenate them on the fly.

Yeah, I was wondering about that.  Just storing them as separate
two-file pair on the server side and serving it as if it is a single
file to the client does not sound like a rocket science, and a
reasonable webserver should be able to serve even a byte-range
request out of such a thing.

Of course, updating the clients to understand such a two-file pair
as a valid bundle is a good thing to do, and I like that step 0. you
outlined below.

>   0. During gc, server generates pack-1234abcd.pack. It writes matching
>      tips into pack-1234abcd.info, which is essentially a bundle file
>      whose final line says "pack-1234abcd.pack".
>
>   1. Client contacts server via any git protocol. Server says
>      "resumable=<url>". Let's says that <url> is
>      https://example.com/repo/clones/1234abcd.bundle.
>
>   2. Client goes to <url>. They see that they are fetching a bundle,
>      and know not to do the usual smart-http or dumb-http protocols.
>      They can fetch the bundle header resumably (though it's tiny, so it
>      doesn't really matter).
> ...