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From: Jonathan Nieder <jrnieder@gmail.com>
To: Christian Couder <christian.couder@gmail.com>
Cc: "Jonathan Tan" <jonathantanmy@google.com>,
	git <git@vger.kernel.org>, "Junio C Hamano" <gitster@pobox.com>,
	"Jeff King" <peff@peff.net>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [WIP 0/7] CDN offloading of fetch response
Date: Thu, 28 Feb 2019 15:21:08 -0800	[thread overview]
Message-ID: <20190228232108.GA163714@google.com> (raw)
In-Reply-To: <CAP8UFD1tKNFO9wU8CbgNnSnQyvHYPsZMk1Bit2y1jxH4vk62qQ@mail.gmail.com>

Hi,

Sorry for the slow followup.  Thanks for probing into the design ---
this should be useful for getting the docs to be clear.

Christian Couder wrote:

> So it's likely that users will want a way to host on such sites
> incomplete repos using CDN offloading to a CDN on another site. And
> then if the CDN is not accessible for some reason, things will
> completely break when users will clone.

I think this would be a broken setup --- we can make it clear in the
protocol and server docs that you should only point to a CDN for which
you control the contents, to avoid breaking clients.

That doesn't prevent adding additional features in the future e.g. for
"server suggested alternates" --- it's just that I consider that a
separate feature.

Using CDN offloading requires cooperation of the hosting provider.
It's a way to optimize how fetches work, not a way to have a partial
repository on the server side.

[...]
> On Tue, Feb 26, 2019 at 12:45 AM Jonathan Nieder <jrnieder@gmail.com> wrote:

>> This doesn't stop a hosting provider from using e.g. server options to
>> allow the client more control over how their response is served, just
>> like can be done for other features of how the transfer works (how
>> often to send progress updates, whether to prioritize latency or
>> throughput, etc).
>
> Could you give a more concrete example of what could be done?

What I mean is passing server options using "git fetch --server-option".
For example:

	git fetch -o priority=BATCH origin master

or

	git fetch -o avoid-cdn=badcdn.example.com origin master

The interpretation of server options is up to the server.

>> What the client *can* do is turn off support for packfile URLs in a
>> request completely.  This is required for backward compatibility and
>> allows working around a host that has configured the feature
>> incorrectly.
>
> If the full content of a repo is really large, the size of a full pack
> file sent by an initial clone could be really big and many client
> machines could not have enough memory to deal with that. And this
> suppose that repo hosting providers would be ok to host very large
> repos in the first place.

Do we require the packfile to fit in memory?  If so, we should fix
that (to use streaming instead).

Thanks,
Jonathan

  parent reply	other threads:[~2019-02-28 23:21 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-23 23:38 [WIP 0/7] CDN offloading of fetch response Jonathan Tan
2019-02-23 23:38 ` [WIP 1/7] http: use --stdin and --keep when downloading pack Jonathan Tan
2019-02-23 23:38 ` [WIP 2/7] http: improve documentation of http_pack_request Jonathan Tan
2019-02-23 23:38 ` [WIP 3/7] http-fetch: support fetching packfiles by URL Jonathan Tan
2019-02-23 23:38 ` [WIP 4/7] Documentation: order protocol v2 sections Jonathan Tan
2019-02-23 23:38 ` [WIP 5/7] Documentation: add Packfile URIs design doc Jonathan Tan
2019-02-23 23:39 ` [WIP 6/7] upload-pack: refactor reading of pack-objects out Jonathan Tan
2019-02-23 23:39 ` [WIP 7/7] upload-pack: send part of packfile response as uri Jonathan Tan
2019-02-24 15:54   ` Junio C Hamano
2019-02-25 21:04   ` Christian Couder
2019-02-26  1:53     ` Jonathan Nieder
2019-02-26  7:08       ` Christian Couder
2019-03-01  0:09   ` Josh Steadmon
2019-03-01  0:17     ` Jonathan Tan
2019-02-25 21:30 ` [WIP 0/7] CDN offloading of fetch response Christian Couder
2019-02-25 23:45   ` Jonathan Nieder
2019-02-26  8:30     ` Christian Couder
2019-02-26  9:12       ` Ævar Arnfjörð Bjarmason
2019-03-04  8:24         ` Christian Couder
2019-02-28 23:21       ` Jonathan Nieder [this message]
2019-03-04  8:54         ` Christian Couder
2019-03-08 21:55 ` [PATCH v2 0/8] " Jonathan Tan
2019-03-08 21:55   ` [PATCH v2 1/8] http: use --stdin when getting dumb HTTP pack Jonathan Tan
2019-03-08 21:55   ` [PATCH v2 2/8] http: improve documentation of http_pack_request Jonathan Tan
2019-03-08 21:55   ` [PATCH v2 3/8] http-fetch: support fetching packfiles by URL Jonathan Tan
2019-03-08 21:55   ` [PATCH v2 4/8] Documentation: order protocol v2 sections Jonathan Tan
2019-03-08 21:55   ` [PATCH v2 5/8] Documentation: add Packfile URIs design doc Jonathan Tan
2019-04-23  5:31     ` Jeff King
2019-04-23 20:38       ` Jonathan Tan
2019-04-23 22:18         ` Ævar Arnfjörð Bjarmason
2019-04-23 22:22           ` Jonathan Nieder
2019-04-23 22:30             ` Ævar Arnfjörð Bjarmason
2019-04-23 22:51               ` Jonathan Nieder
2019-04-23 22:11       ` Jonathan Nieder
2019-04-23 22:25         ` Ævar Arnfjörð Bjarmason
2019-04-23 22:48           ` Jonathan Nieder
2019-04-24  7:48             ` Ævar Arnfjörð Bjarmason
2019-04-24  3:01       ` Junio C Hamano
2019-03-08 21:55   ` [PATCH v2 6/8] upload-pack: refactor reading of pack-objects out Jonathan Tan
2019-03-08 21:55   ` [PATCH v2 7/8] fetch-pack: support more than one pack lockfile Jonathan Tan
2019-03-08 21:55   ` [PATCH v2 8/8] upload-pack: send part of packfile response as uri Jonathan Tan
2019-03-19 20:48   ` [PATCH v2 0/8] CDN offloading of fetch response Josh Steadmon
2019-04-23  5:21   ` Jeff King
2019-04-23 19:23     ` Jonathan Tan
2019-04-24  9:09   ` Ævar Arnfjörð Bjarmason

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