[Qemu-devel] https:// for GIT submodules / "smart" HTTP protocol on git.qemu.git

["Daniel P. Berrangé" <berrange@redhat.com>]

Most of QEMU regular developers are fortunate to have unfiltered internet
access which allows using the git:// protocol. People working in more
old fashioned / paranoid environments often find access to anything other
than http(s) blocked by firewalls. They'll get a bad experiance when trying
to build QEMU, when we try to initialize the git submodules and git://
protocol fails to connect.

We could improve life for people behind such nasty firewalls if we made our
GIT submodules use https:// URIs, instead of git:// URIs. There is one snag.

Historically git:// URIs were strongly preferred over http(s):// URIs for
reasons for performance. Modern GIT though, supports both the traditional
"dumb" HTTP protocol (which is horribly slow) and a modern "smart" HTTP
protocol whose performance matches that of git:/// URIs.

Unfortunately it seems that git.qemu.org is not configured to enable the
smart HTTP protocol.

So can we get a todo item for git.qemu.org get the web server setup to
enable the smart GIT protocol, so we can then enable use of http:// by
default for all the submodules to improve life for contributors.

FYI, you can validate if a server supports the smart protocol or not
by querying  $REPO_URI/info/refs?service=git-upload-pack and seeing
if the response includes a header

   Content-Type: application/x-git-upload-pack-advertisement

qemu.org does not:

  $ wget -S  'https://git.qemu.org/git/qemu.git/info/refs?service=git-upload-pack' 2>&1 | grep Content-Type

and shows terrible git clone performance for http:// uris

but github for example does

  $ wget -S  'https://github.com/qemu/qemu.git/info/refs?service=git-upload-pack' 2>&1 | grep Content-Type
  Content-Type: application/x-git-upload-pack-advertisement

and shows great performance for http:// URIs

Regards,
Daniel
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