From: Rutger Nijlunsing <rutger@nospam.com>
Subject: Setting up a git repository which can be pushed into and pulled from over HTTP(S).
Date: Thu, 10 Aug 2006 22:00:26 +0200

Since Apache is one of those packages people like to compile
themselves while others prefer the bureaucrat's dream Debian, it is
impossible to give guidelines which will work for everyone. Just send
some feedback to the mailing list at git@vger.kernel.org to get this
document tailored to your favorite distro.


What's needed:

- Have an Apache web-server

  On Debian:
    $ apt-get install apache2
    To get apache2 by default started,
    edit /etc/default/apache2 and set NO_START=0

- can edit the configuration of it.

  This could be found under /etc/httpd, or refer to your Apache documentation.

  On Debian: this means being able to edit files under /etc/apache2

- can restart it.

  'apachectl --graceful' might do. If it doesn't, just stop and
  restart apache. Be warning that active connections to your server
  might be aborted by this.

  On Debian:
    $ /etc/init.d/apache2 restart
  or
    $ /etc/init.d/apache2 force-reload
    (which seems to do the same)
  This adds symlinks from the /etc/apache2/mods-enabled to
  /etc/apache2/mods-available.

- have permissions to chown a directory

- have git installed on the client, and

- either have git installed on the server or have a webdav client on
  the client.

In effect, this means you're going to be root, or that you're using a
preconfigured WebDAV server.


Step 1: setup a bare GIT repository
-----------------------------------

At the time of writing, git-http-push cannot remotely create a GIT
repository. So we have to do that at the server side with git. Another
option is to generate an empty bare repository at the client and copy
it to the server with a WebDAV client (which is the only option if Git
is not installed on the server).

Create the directory under the DocumentRoot of the directories served
by Apache. As an example we take /usr/local/apache2, but try "grep
DocumentRoot /where/ever/httpd.conf" to find your root:

    $ cd /usr/local/apache/htdocs
    $ mkdir my-new-repo.git

  On Debian:

    $ cd /var/www
    $ mkdir my-new-repo.git


Initialize a bare repository

    $ cd my-new-repo.git
    $ git --bare init


Change the ownership to your web-server's credentials. Use "grep ^User
httpd.conf" and "grep ^Group httpd.conf" to find out:

    $ chown -R www.www .

  On Debian:

    $ chown -R www-data.www-data .


If you do not know which user Apache runs as, you can alternatively do
a "chmod -R a+w .", inspect the files which are created later on, and
set the permissions appropriately.

Restart apache2, and check whether http://server/my-new-repo.git gives
a directory listing. If not, check whether apache started up
successfully.


Step 2: enable DAV on this repository
-------------------------------------

First make sure the dav_module is loaded. For this, insert in httpd.conf:

    LoadModule dav_module libexec/httpd/libdav.so
    AddModule mod_dav.c

Also make sure that this line exists which is the file used for
locking DAV operations:

  DAVLockDB "/usr/local/apache2/temp/DAV.lock"

  On Debian these steps can be performed with:

    Enable the dav and dav_fs modules of apache:
    $ a2enmod dav_fs
    (just to be sure. dav_fs might be unneeded, I don't know)
    $ a2enmod dav
    The DAV lock is located in /etc/apache2/mods-available/dav_fs.conf:
      DAVLockDB /var/lock/apache2/DAVLock

Of course, it can point somewhere else, but the string is actually just a
prefix in some Apache configurations, and therefore the _directory_ has to
be writable by the user Apache runs as.

Then, add something like this to your httpd.conf

  <Location /my-new-repo.git>
     DAV on
     AuthType Basic
     AuthName "Git"
     AuthUserFile /usr/local/apache2/conf/passwd.git
     Require valid-user
  </Location>

  On Debian:
    Create (or add to) /etc/apache2/conf.d/git.conf :

    <Location /my-new-repo.git>
       DAV on
       AuthType Basic
       AuthName "Git"
       AuthUserFile /etc/apache2/passwd.git
       Require valid-user
    </Location>

    Debian automatically reads all files under /etc/apach2/conf.d.

The password file can be somewhere else, but it has to be readable by
Apache and preferably not readable by the world.

Create this file by
    $ htpasswd -c /usr/local/apache2/conf/passwd.git <user>

    On Debian:
      $ htpasswd -c /etc/apache2/passwd.git <user>

You will be asked a password, and the file is created. Subsequent calls
to htpasswd should omit the '-c' option, since you want to append to the
existing file.

You need to restart Apache.

Now go to http://<username>@<servername>/my-new-repo.git in your
browser to check whether it asks for a password and accepts the right
password.

On Debian:

   To test the WebDAV part, do:

   $ apt-get install litmus
   $ litmus http://<servername>/my-new-repo.git <username> <password>

   Most tests should pass.

A command line tool to test WebDAV is cadaver. If you prefer GUIs, for
example, konqueror can open WebDAV URLs as "webdav://..." or
"webdavs://...".

If you're into Windows, from XP onwards Internet Explorer supports
WebDAV. For this, do Internet Explorer -> Open Location ->
http://<servername>/my-new-repo.git [x] Open as webfolder -> login .


Step 3: setup the client
------------------------

Make sure that you have HTTP support, i.e. your git was built with
libcurl (version more recent than 7.10). The command 'git http-push' with
no argument should display a usage message.

Then, add the following to your $HOME/.netrc (you can do without, but will be
asked to input your password a _lot_ of times):

    machine <servername>
    login <username>
    password <password>

...and set permissions:
     chmod 600 ~/.netrc

If you want to access the web-server by its IP, you have to type that in,
instead of the server name.

To check whether all is OK, do:

   curl --netrc --location -v http://<username>@<servername>/my-new-repo.git/HEAD

...this should give something like 'ref: refs/heads/master', which is
the content of the file HEAD on the server.

Now, add the remote in your existing repository which contains the project
you want to export:

   $ git-config remote.upload.url \
       http://<username>@<servername>/my-new-repo.git/

It is important to put the last '/'; Without it, the server will send
a redirect which git-http-push does not (yet) understand, and git-http-push
will repeat the request infinitely.


Step 4: make the initial push
-----------------------------

From your client repository, do

   $ git push upload master

This pushes branch 'master' (which is assumed to be the branch you
want to export) to repository called 'upload', which we previously
defined with git-config.


Using a proxy:
--------------

If you have to access the WebDAV server from behind an HTTP(S) proxy,
set the variable 'all_proxy' to 'http://proxy-host.com:port', or
'http://login-on-proxy:passwd-on-proxy@proxy-host.com:port'. See 'man
curl' for details.


Troubleshooting:
----------------

If git-http-push says

   Error: no DAV locking support on remote repo http://...

then it means the web-server did not accept your authentication. Make sure
that the user name and password matches in httpd.conf, .netrc and the URL
you are uploading to.

If git-http-push shows you an error (22/502) when trying to MOVE a blob,
it means that your web-server somehow does not recognize its name in the
request; This can happen when you start Apache, but then disable the
network interface. A simple restart of Apache helps.

Errors like (22/502) are of format (curl error code/http error
code). So (22/404) means something like 'not found' at the server.

Reading /usr/local/apache2/logs/error_log is often helpful.

  On Debian: Read /var/log/apache2/error.log instead.

If you access HTTPS locations, git may fail verifying the SSL
certificate (this is return code 60). Setting http.sslVerify=false can
help diagnosing the problem, but removes security checks.


Debian References: http://www.debian-administration.org/articles/285

Authors
  Johannes Schindelin <Johannes.Schindelin@gmx.de>
  Rutger Nijlunsing <git@wingding.demon.nl>
  Matthieu Moy <Matthieu.Moy@imag.fr>
