Re: [PATCH v2 4/4] bundle v3: the beginning

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 3, 2016, 02:57 UTC
Message-ID: <xmqqwppk2rqo.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <CACsJy8AzZsC3_7mWQutko8W=X1Lch3bMZRjoHtjVnWwtbMBt7A@mail.gmail.com>

Duy Nguyen <pclouds@gmail.com> writes:

Show 5 quoted lines

> would it be
> ok if we introduced a minimal resumable download service via
> git-daemon to enable this feature with very little setup? Like
> git-shell, you can only download certain packfiles for this use case
> and nothing else with this service.

I think it is a matter of priorities.

A minimalistic site that offers only git-daemon traffic without a working HTTP server would certainly benefit from such a thing, but serving static files efficiently over the web is commodity service these days. Wouldn't it be sufficient to just recommend having a normal HTTP server serving static files, which should be "very little setup" in today's world?

Such a "minimal resumable download service" over the git-daemon transport still has to reinvent what is already done well by the HTTP servers and clients (e.g. support of ETag equivalent to make sure that the client can notice that the underlying data has changed for a given resource, headers to communicate the total length, making a range request and responding to it, etc. etc.).

In addition,, by going the custom protocol route, you wouldn't benefit from caching HTTP proxies available to the clients.

So I am not sure if the benefit outweighs the cost.

I wouldn't stop you if you really want to do it, but again, it is a matter of priorities. I personally feel that it would be a waste of engineering talent, and it certainly would be a waste of review bandwidth, if you gave priority to this over other more widely useful parts of the system. The procedure to repack should be updated to produce such a base pack with the separate bundle header on the server side, the protocol needs to be updated to allow redirection for "clone" traffic, the logic to decide when to redirect must be designed (e.g. "single branch" clone should not choose a pack/bundle that represents the full repository, but a pack for the branch that was asked), etc. There are still tons of things that need to be done, and it would be a distraction to invent a custom download service nobody other than git-daemon talks before all of the above is done.