summaryrefslogtreecommitdiff
path: root/doc/rcs/git.mdwn
blob: deddfbd6d4c930b3a7978881215bbdd6c6fd00a0 (plain)

[[!meta title="Git"]]

Git is a distributed revison control system originally developed for the Linux kernel. Ikiwiki supports storing a wiki in git.

Ikiwiki can run as a post-update hook to update a wiki whenever commits come in. When running as a [[cgi]] with Git, ikiwiki automatically commits edited pages, and uses the Git history to generate the [[RecentChanges]] page.

git repository setup

The suggested setup for git is a set of repositories setup like a shallow, single level tree, with a bare repository (meaning that it does not have a working tree checked out) at the root, and various working clones (with working directories) as leaf nodes. The root (bare) repository is meant to be pushed to and pulled from the various working clones.

One of the leaf node clone repositories is special; it has working directory which is used to compile the wiki from, and is also used by the [[cgi]] to commit changes made via the web interface. It is special since the post-commit hook for the bare root repository is used to trigger an update of this repository, and then an ikiwiki refresh updates the published wiki itself.

The other (optional) leaf node repositories are meant for you to work on, and commit to, changes should then be pushed to the bare root repository. In theory, you could work on the same leaf node repository that ikiwiki uses to compile the wiki from, and the [[cgi]] commits to, as long as you ensure that permissions and ownership don't hinder the working of the [[cgi]]. This can be done, for example, by using ACL's, in practice, it is easier to just setup separate clones for yourself.

So, to reiterate, when using Git, you probably want to set up three repositories:

  • The root repository. This should be a bare repository (meaning that it does not have a working tree checked out), which the other repositories will push to/pull from. It is a bare repository, since there are problems pushing to a repository that has a working directory. This is called repository in [[ikiwiki-makerepo]]'s manual page. Nominally, this bare repository has a post-commit hook that either is or calls ikiwiki's git wrapper, which changes to the working directory for ikiwiki, does a git pull, and refreshes ikiwiki to regenerate the wiki with any new content. The [[setup]] page describes how to do this.

  • The second repository is a clone of the bare root repository, and has a working tree which is used as ikiwiki's srcdir for compiling the wiki. Never push to this repository. When running as a [[cgi]], the changes are committed to this repository, and pushed to the master repository above. This is called srcdir in [[ikiwiki-makerepo]]'s manual page.

  • The other (third, fourth, fifth, sixth -- however many pleases you) repositories are also clones of the bare root repository above -- and these have a working directory for you to work on. Use either the git transport (if available), or ssh. These repositories may be on remote machines, your laptop, whereever you find convenient to hack on your wiki. you can commit local changes to the version on the laptop, perhaps while offline. Any new content should be pushed to the bare master repository when you are ready to publish it, and then the post-commit hook of the bare repository will ensure that the ikiwiki's source directory is updated, and the ikiwiki refreshed with the new content.

Using three or more of repositories isn't the most obvious set up, but it works the best for typical ikiwiki use. [[ikiwiki-makerepo]] can automate setting this up for the common case where there is no pre-existing wiki. [[tips/Laptop_wiki_with_git]] describes a different way to set up ikiwiki and git.

It is paramount that you never push to the non-bare repository (this FAQ entry explains why). Instead, clone the bare repository as mentioned above, and push only to the bare repository.

The ikiwiki post-commit hook should be put in the bare repository.

git repository with multiple committers

It can be tricky to get the permissions right to allow multiple people to commit to an ikiwiki git repository. As the [[security]] page mentions, for a secure ikiwiki installation, only one person should be able to write to ikiwiki's srcdir. When other committers make commits, their commits should go to the bare repository, which has a post-update hook that uses ikiwiki to pull the changes to the srcdir.

One setup that will work is to put all committers in a group (say, "ikiwiki"), and use permissions to allow that group to commit to the bare git repository. Make both the post-update hook and ikiwiki.cgi be setgid to the group, as well as suid to the user who admins the wiki. The wrappergroup [[setup_file_option|usage]] can be used to make the wrappers be setgid to the right group. Then the srcdir, including its git repository, should only be writable by the wiki's admin, and not by the group. Take care that ikiwiki uses a umask that does not cause files in the srcdir to become group writable. (umask 022 will work.)

git repository with untrusted committers

By default, anyone who can commit to the git repository can modify any file on the wiki however they like. A pre-receive hook can be set up to limit incoming commits from untrusted users. Then the same limits that are placed on edits via the web will be in effect for commits to git for the users. They will not be allowed to edit locked pages, they will only be able to delete pages that the [[plugins/remove]] configuration allows them to remove, and they will only be allowed to add non-page attachments that the [[plugins/attachment]] configuration allows.

To enable this, you need to set up the git repository to have multiple committers. Trusted committers, including the user that ikiwiki runs as, will not have their commits checked by the pre-receive hook. Untrusted committers will have their commits checked. The configuration settings to enable are git_test_receive_wrapper, which enables generation of a pre-receive hook, and untrusted_committers, which is a list of usernames of the untrusted committers.

Note that when the pre-receive hook is checking incoming changes, it ignores the git authorship information, and uses the username of the unix user who made the commit. Then tests including the locked_pages [[PageSpec]] are checked to see if that user can edit the pages in the commit.

You can even set up an [[anonymous_user|tips/untrusted_git_push]], to allow anyone to push changes in via git rather than using the web interface.

Optionally using a local wiki to preview changes

When working on the "working clones" to add content to your wiki, it is common (but optional) practice to preview your changes using a private wiki on the local host before publishing the updates by sending it to the root repository. If you do want to setup a private wiki, you will have to have another setup file and and an ikiwiki installation on your local machine. You will need all the packages this implies -- a web server, git, ikiwiki, etc. However, there is a caveat: by default, ikiwiki pulls and pushes from origin. This is not ideal for the working clones on the local machine, since you might go through several iterations of a page before pushing to the bare root of the repository tree (and thus publishing it on your public wiki). You do not want the action of refreshing the local wiki in order to review your work to accidentally publish the contents before you are ready. In order to prevent the git push that is the normal behaviour of ikiwiki, set the configuration of the local wiki:

  gitorigin_branch => "",
  ## git post-commit wrapper
  wrapper => "/working/dir/.git/hooks/post-commit",

Then just committing should refresh the private ikiwiki on the local host. Now just run ikiwiki -setup localwiki.setup -getctime and you should be good to go. (You only need the slow -getctime option the first time you run setup.) Use standard git commands to handle pulling from and pushing to the server. Note: Currently, after pulling changes from the bare root repository, you will need to manually update the local wiki, with a command such as ikiwiki -setup localwiki.setup -refresh. This is because git 1.5.4 doesn't have a hook that is run locally after pulling changes. Newer versions of git will have a post-merge hook that should work for this purpose.

Fix for error on git pull origin

Error message when running git pull origin:

You asked me to pull without telling me which branch you
want to merge with, and 'branch.master.merge' in
your configuration file does not tell me either.  Please
name which branch you want to merge on the command line and
try again (e.g. 'git pull <repository> <refspec>').
See git-pull(1) for details on the refspec.

If you often merge with the same branch, you may want to
configure the following variables in your configuration
file:

    branch.master.remote = <nickname>
    branch.master.merge = <remote-ref>
    remote.<nickname>.url = <url>
    remote.<nickname>.fetch = <refspec>

See git-config(1) for details.

The solution is to run this command in your srcdir:

git config branch.master.remote origin