Merge branch 'master' of git://github.com/joeyh/ikiwiki

4 files changed, 161 insertions, 2 deletions

diff --git a/doc/plugins/contrib/cvs.mdwn b/doc/plugins/contrib/cvs.mdwn
index 23e00201f..6b600eef7 100644
--- a/doc/plugins/contrib/cvs.mdwn
+++ b/doc/plugins/contrib/cvs.mdwn
@@ -22,8 +22,7 @@ Consider creating `$HOME/.cvsrc` if you don't have one already; the plugin doesn
 * [[ikiwiki-makerepo]]:
  * creates a repository,
  * imports `$SRCDIR` into top-level module `ikiwiki` (vendor tag IKIWIKI, release tag PRE_CVS),
- * creates a small post-commit wrapper to prevent `cvs add <directory>` from being seen by ikiwiki's [[post-commit]] hook (and avoid `cvs` locking against itself),
- * configures the wrapper itself as a post-commit hook in `CVSROOT/loginfo`.
+ * configures the post-commit hook in `CVSROOT/loginfo`.
 * CVS multi-directory commits happen separately; the post-commit hook sees only the first directory's changes in time for [[recentchanges|plugins/recentchanges]]. The next run of `ikiwiki --setup` will correctly re-render such a recentchanges entry. It should be possible to solve this problem with NetBSD's `commit_prep` and `log_accum` scripts (see below).
 
 ### To do
diff --git a/doc/plugins/contrib/cvs/discussion.mdwn b/doc/plugins/contrib/cvs/discussion.mdwn
new file mode 100644
index 000000000..e1fa6e428
--- /dev/null
+++ b/doc/plugins/contrib/cvs/discussion.mdwn
@@ -0,0 +1,91 @@
+I've started reviewing this, and the main thing I don't like is the
+post-commit wrapper wrapper that ikiwiki-makerepo is patched to set up.
+That just seems unnecessarily complicated. Why can't ikiwiki itself detect
+the "cvs add <directory>" call and avoid doing anything in that case?
+--[[Joey]] 
+
+> The wrapper wrapper does three things:
+>
+> 7. It ignores `cvs add <directory>`, since this is a weird CVS
+> behavior that ikiwiki gets confused by and doesn't need to act on.
+> 7. It prevents `cvs` locking against itself: `cvs commit` takes a
+> write lock and runs the post-commit hook, which runs `cvs update`,
+> which wants a read lock and sleeps forever -- unless the post-commit
+> hook runs in the background so the commit can "finish".
+> 7. It fails silently if the ikiwiki post-commit hook is missing.
+> CVS doesn't have any magic post-commit filenames, so hooks have to
+> be configured explicitly. I don't think a commit will actually fail
+> if a configured post-commit hook is missing (though I can't test
+> this at the moment).
+>
+> Thing 1 can probably be handled within ikiwiki, if that seems less
+> gross to you.
+
+>> It seems like it might be. You can use a `getopt` hook to check
+>> `@ARGV` to see how it was called. --[[Joey]] 
+
+>>> This does the trick iff the post-commit wrapper passes its args
+>>> along. Committed on my branch. This seems potentially dangerous,
+>>> since the args passed to ikiwiki are influenced by web commits.
+>>> I don't see an exploit, but for paranoia's sake, maybe the wrapper
+>>> should only be built with execv() if the cvs plugin is loaded?
+>>> --[[schmonz]]
+
+>>>> Hadn't considered that. While in wrapper mode the normal getopt is not
+>>>> done, plugin getopt still runs, and so any unsafe options that 
+>>>> other plugins support could be a problem if another user runs
+>>>> the setuid wrapper and passes those options through. --[[Joey]]
+
+>>>>> I've tried compiling the argument check into the wrapper as
+>>>>> the first thing main() does, and was surprised to find that
+>>>>> this doesn't prevent the `cvs add <dir>` deadlock in a web
+>>>>> commit. I was convinced this'd be a reasonable solution,
+>>>>> especially if conditionalized on the cvs plugin being loaded,
+>>>>> but it doesn't work. And I stuck debug printfs at the beginning
+>>>>> of all the rcs_foo() subs, and whatever `cvs add <dir>` is
+>>>>> doing to ikiwiki isn't visible to my plugin, because none of
+>>>>> those subs are getting called. Nuts. Can you think of anything
+>>>>> else that might solve the problem, or should I go back to
+>>>>> generating a minimal wrapper wrapper that checks for just
+>>>>> this one thing? --[[schmonz]]
+
+>>>>>> I don't see how there could possibly be a difference between
+>>>>>> ikiwiki's C wrapper and your shell wrapper wrapper here. --[[Joey]]
+
+> Thing 2 I'm less sure of. (I'd like to see the web UI return
+> immediately on save anyway, to a temporary "rebuilding, please wait
+> if you feel like knowing when it's done" page, but this problem
+> with CVS happens with any kind of commit, and could conceivably
+> happen with some other VCS.)
+
+>> None of the other VCSes let a write lock block a read lock, apparently.
+>> 
+>> Anyway, re the backgrounding, when committing via the web, the
+>> post-commit hook doesn't run anyway; the rendering is done via the
+>> ikiwiki CGI. It would certianly be nice if it popped up a quick "working"
+>> page and replaced it with the updated page when done, but that's
+>> unrelated;  the post-commit
+>> hook only does rendering when committing using the VCS directly. The
+>> backgrounding you do actually seems safe enough -- but tacking
+>> on a " &" to the ikiwiki wrapper call doesn't need a wrapper script,
+>> does it? --[[Joey]]
+
+>>> Nope, it works fine to append it to the `CVSROOT/loginfo` line.
+>>> Fixed on my branch. --[[schmonz]]
+
+> Thing 3 I think I did in order to squelch the error messages that
+> were bollixing up the CGI. It was easy to do this in the wrapper
+> wrapper, but if that's going away, it can be done just as easily
+> with output redirection in `CVSROOT/loginfo`.
+>
+> --[[schmonz]]
+
+>> If the error messages screw up the CGI they must go to stdout.
+>> I thought we had stderr even in the the CVS dark ages. ;-) --[[Joey]] 
+
+>>> Some messages go to stderr, but definitely not all. That's why
+>>> I wound up reaching for IPC::Cmd, to execute the command line
+>>> safely while shutting CVS up. Anyway, I've tested what happens
+>>> if a configured post-commit hook is missing, and it seems fine,
+>>> probably also thanks to IPC::Cmd.
+>>> --[[schmonz]]
diff --git a/doc/plugins/contrib/rsync.mdwn b/doc/plugins/contrib/rsync.mdwn
new file mode 100644
index 000000000..71cd63947
--- /dev/null
+++ b/doc/plugins/contrib/rsync.mdwn
@@ -0,0 +1,21 @@
+[[!template id=plugin name=rsync core=0 author="[[schmonz]]"]]
+
+[[!template id=gitbranch branch=schmonz author="[[schmonz]]"]]
+
+This plugin allows ikiwiki to push generated pages to another host
+by running a command such as `rsync`.
+
+### Usage
+7. Enable automated SSH key exchange between ikiwiki and the remote
+   host. [keychain](http://www.gentoo.org/proj/en/keychain/) makes
+   it easy to use a passphrase-protected key for this purpose. It's
+   also a good idea to specify the exact command line to be permitted
+   in the remote host's `$HOME/.ssh/authorized_keys`.
+7. Set `rsync_command` in your setup file. If you're using a
+   passphrase-protected key, then set `rsync_command` to a shell
+   script which reads `keychain`'s current state before calling
+   `rsync`.
+
+### Implementation details
+* The plugin relies on a new "postrefresh" hook called at the very end of
+  `IkiWiki/Render.pm:refresh()`.
diff --git a/doc/plugins/contrib/rsync/discussion.mdwn b/doc/plugins/contrib/rsync/discussion.mdwn
new file mode 100644
index 000000000..20c04af0f
--- /dev/null
+++ b/doc/plugins/contrib/rsync/discussion.mdwn
@@ -0,0 +1,48 @@
+## A use case
+
+Why I needed this plugin: I have two web servers available to me
+for a project. Neither does everything I need, but together they
+do. (This is a bit like the [Amazon S3
+scenario](http://kitenet.net/~joey/blog/entry/running_a_wiki_on_Amazon_S3/).)
+
+Server (1) is a university web server. It provides plentiful space
+and bandwidth, easy authentication for people editing the wiki, and
+a well-known stable URL. The wiki really wants to live here and
+very easily could except that the server doesn't allow arbitrary
+CGIs.
+
+Server (2) is provided by a generous alumnus's paid [[tips/DreamHost]]
+account. Disk and particularly network usage need to be minimized
+because over some threshold it costs him. CGI, etc. are available.
+
+My plan was to host the wiki on server (1) by taking advantage of
+server (2) to store the repository, source checkout, and generated
+pages, to host the repository browser, and to handle ikiwiki's CGI
+operations. In order for this to work, web edits on (2) would need
+to automatically push any changed pages to (1).
+
+As a proof of concept, I added an rsync post-commit hook after
+ikiwiki's usual. It worked, just not for web edits, which is how
+the wiki will be used. So I wrote this plugin to finish the job.
+The wiki now lives on (1), and clicking "edit" just works. --[[schmonz]]
+
+> Just out of interest, why use `rsync` and not `git push`.  i.e. a
+> different setup to solve the same problem would be to run a
+> normal ikiwiki setup on the universities server with its git
+> repository available over ssh (same security setup your using
+> for rsync should work for git over ssh).  On the cgi-capable server,
+> when it would rsync, make it git push.  It would seem that git
+> has enough information that it should be able to be more
+> network efficient.  It also means that corruption at one end
+> wouldn't be propagated to the other end. -- [[Will]]
+
+>> Hey, that's a nice solution. (The site was in svn to begin with,
+>> but it's in git now.) One advantage of my approach in this particular
+>> case: server (1) doesn't have `git` installed, but does have `rsync`,
+>> so (1)'s environment can remain completely untweaked other than the
+>> SSH arrangement. I kind of like that all the sysadmin effort is
+>> contained on one host.
+>>
+>> This plugin is definitely still useful for projects not able to use
+>> a DVCS (of which I've got at least one other), and possibly for
+>> other uses not yet imagined. ;-) --[[schmonz]]