Re: Can't get 'git archive' to work

From: Jeff King <peff@peff.net>
Date: Dec 7, 2015, 20:39 UTC
Message-ID: <20151207203900.GB30203@sigill.intra.peff.net>
In-Reply-To: <5665199A.7070304@rawbw.com>

On Sun, Dec 06, 2015 at 09:31:06PM -0800, Yuri wrote:

> Why "operation is not supported" through http and https? 'archive' is
> supposed to be the most efficient operation to get the specific snapshot of
> the repository, and it should be available without authentication.

Remote git-archive is not well-supported. It does work over git-daemon, but the server side has to explicitly turn it on in their config. It was never plumbed into the git-over-http protocol at all. ssh is generally the only place it works out-of-the-box (but see below).

Show 10 quoted lines

> In case of ssh with the key there is the strange error message about
> "core.gitProxy". What is this about? I am not using a proxy.
> [...]
> # through ssh with an active ssh key
> $ git archive --format=tar --remote=git@github.com:yurivict/vm-to-tor.git
> Invalid command: 'git-upload-archive 'yurivict/vm-to-tor.git''
>   You appear to be using ssh to clone a git:// URL.
>   Make sure your core.gitProxy config option and the
>   GIT_PROXY_COMMAND environment variable are NOT set.
> fatal: The remote end hung up unexpectedly

This message isn't from git, but rather from GitHub's ssh server. You can see it here without running git locally at all:

  $ ssh git@github.com git-upload-archive
  Invalid command: 'git-upload-archive'
  You appear to be using ssh to clone a git:// URL.
  Make sure your core.gitProxy config option and the
  GIT_PROXY_COMMAND environment variable are NOT set.

The short of it is that GitHub does not support remote git-archive at all, not even over ssh. Part of the reason is that it maintains a separate caching layer for grabbing zips and tarballs, which is available at an http endpoint:

  https://github.com/yurivict/vm-to-tor/archive/master.tar.gz

Clearly the advice above is not helpful in this case; I don't recall the case that it was originally written to help. You may want to write to GitHub support about it.

> # through ssh without an ssh key
> $  git archive --format=tar --remote=git@github.com:yurivict/vm-to-tor.git
> Permission denied (publickey).
> fatal: The remote end hung up unexpectedly

GitHub's ssh server only accepts key authentication, so this is not surprising.

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> # through https
> $  git archive --format=tar
> --remote=https://github.com/yurivict/vm-to-tor.git
> fatal: Operation not supported by protocol.
> 
> # through http
> $  git archive --format=tar
> --remote=http://github.com/yurivict/vm-to-tor.git
> fatal: Operation not supported by protocol.

This comes from the local git client. There's no scheme defined for hitting git-upload-archive (the server side of a remote git-archive) over HTTP. You'd have to define it, implement the client side of it, and then convince the server side to configure their HTTP servers to handle it as a CGI. That might be a nice project to work on, but it will not get you tarballs anytime soon. :)

-Peff