Subject: [HOWTO] Using post-update hook Message-ID: <7vy86o6usx.fsf@assigned-by-dhcp.cox.net> From: Junio C Hamano Date: Fri, 26 Aug 2005 18:19:10 -0700 Abstract: In this how-to article, JC talks about how he uses the post-update hook to automate git documentation page shown at http://www.kernel.org/pub/software/scm/git/docs/. The pages under http://www.kernel.org/pub/software/scm/git/docs/ are built from Documentation/ directory of the git.git project and needed to be kept up-to-date. The www.kernel.org/ servers are mirrored and I was told that the origin of the mirror is on the machine $some.kernel.org, on which I was given an account when I took over git maintainership from Linus. The directories relevant to this how-to are these two: /pub/scm/git/git.git/ The public git repository. /pub/software/scm/git/docs/ The HTML documentation page. So I made a repository to generate the documentation under my home directory over there. $ cd $ mkdir doc-git && cd doc-git $ git clone /pub/scm/git/git.git/ docgen What needs to happen is to update the $HOME/doc-git/docgen/ working tree, build HTML docs there and install the result in /pub/software/scm/git/docs/ directory. So I wrote a little script: $ cat >dododoc.sh <<\EOF #!/bin/sh cd $HOME/doc-git/docgen || exit unset GIT_DIR git pull /pub/scm/git/git.git/ master && cd Documentation && make install-webdoc EOF Initially I used to run this by hand whenever I push into the public git repository. Then I did a cron job that ran twice a day. The current round uses the post-update hook mechanism, like this: $ cat >/pub/scm/git/git.git/hooks/post-update <<\EOF #!/bin/sh # # An example hook script to prepare a packed repository for use over # dumb transports. # # To enable this hook, make this file executable by "chmod +x post-update". case " $* " in *' refs/heads/master '*) echo $HOME/doc-git/dododoc.sh | at now ;; esac exec git-update-server-info EOF $ chmod +x /pub/scm/git/git.git/hooks/post-update There are four things worth mentioning: - The update-hook is run after the repository accepts a "git push", under my user privilege. It is given the full names of refs that have been updated as arguments. My post-update runs the dododoc.sh script only when the master head is updated. - When update-hook is run, GIT_DIR is set to '.' by the calling receive-pack. This is inherited by the dododoc.sh run via the "at" command, and needs to be unset; otherwise, "git pull" it does into $HOME/doc-git/docgen/ repository would not work correctly. - The stdout of update hook script is not connected to git push; I run the heavy part of the command inside "at", to receive the execution report via e-mail. - This is still crude and does not protect against simultaneous make invocations stomping on each other. I would need to add some locking mechanism for this.