gitolite/doc/developer-notes.mkd
Sitaram Chamarty 6e29365316 MASSIVE set of changes to documents!
I got tired of being told "TL;DR".  Now the online versions of most
documents fit on a page or two, or at least most of them do.  The rest
has been split out (and you can see the links to the split out sections
right where the text is in the raw Markdown).

This is much more pleasant to read, and I've improved the linking so
it's much less effort for me to keep the links correct.
2011-11-02 21:04:33 +05:30

149 lines
5.8 KiB
Markdown

# F=dev_notes developer/patch maintainer notes
## general stuff
* all scripts and libraries must be in the same directory. However, RPM/DEB
packagers can put the libraries where they want, as long as they can be
found in perl's default `@INC`.
* gl-auth-command **requires** an actual `~/.gitolite.rc` (except if your
initials are "JK" or "DG", in which case `/etc/gitolite/gitolite.rc` also
works!) It knows how to look around and set env vars etc correctly
* all programs except gl-auth-command **require** the environment variables
`GL_RC` and `GL_BINDIR` set properly. Your best bet is to run them *via*
gl-auth-command, like so:
path/to/gl-auth-command -e other_program other_program_arguments
In any case none of these programs are meant to be run manually -- pretty
much all of them are run via gl-auth-command or from something that was
forked from it so the variables *will* exist during normal operation.
## the rc file
The 'rc' file has one major change from v1: any new values in the rc file need
to be added to the @EXPORT list in `src/gitolite_rc.pm`.
## modules
There are 3 "modules" (`gitolite_rc`, `gitolite_env`, and `gitolite` itself).
Their purposes should be fairly obvious.
## that 'bindir' thing
The importance of `GL_BINDIR` is that the command= argument in
`~/.ssh/authorized_keys` must be a full path, ideally, and the compile script
gets this from `GL_BINDIR`.
### from perl
* for frequently run perl programs, I prefer my method
* gl-auth-command -- this is invoked with a full path
* gl-mirror-shell -- same as above
* gl-time -- same as above
* "their" ideal is "FindBin". I will use it only on manually or
infrequently run programs
* gl-setup-authkeys (external shim to compile keys separately from PTA)
### from shell
* a perl program called gl-query-rc finds its own BINDIR (using my perl
method, not FindBin). This is suitable for calling from shell scripts
as `${0%/*}/gl-query-rc GL_BINDIR`
* gl-setup
* gl-tool
* gl-mirror-push
### OUTLIER!
* gl-admin-push is an outlier. For some silly reason I have the notion that
even if it runs from /tmp it should get the right values, so it is the
only one that interrogates `~/.ssh/authorized_keys` to get the actual
BINDIR in use!
## special types of setups
### Fedora
Fedora has a very special setup, as follows:
* each user has his own userid and login
* his/her ~/.ssh/authkeys file (containing only his/her key) has a
"command=" clause invoking gl-auth-command
* trusted users have "gl-auth-command -s" meaning they can get a shell if
they want to
* actual git repos are under "git" (or some such), and include the chmod g+s
(git init --shared) unix perms tricks for shared access
* but since they're coming through gl-auth, branch-level acls are in effect
* the gitolite config file is generated from some database and compiled (all
via cron)
* the keydir/ is empty; in fact they probably don't use the admin repo at
all, AFAIK
The most important implication of this setup is that **the RC file is no
longer is `$HOME` of the 'git' user**. They keep it in
`/etc/gitolite/gitolite.rc`. This means that a properly setup rc file must
already be present in `/etc/gitolite/gitolite.rc` before doing any such
installs.
There are also some other "impedance mismatches" that may show up. For
example, the gl-setup triggered by detecting a change in `$data_version`
following an RPM update once caused problems. This auto-update is designed to
run on the next "hit" of any kind (which arguably makes things very easy in
normal installations), but in Fedora's case it also means it runs *as that
user*. Who may not have "write" access to `$GL_ADMINDIR`! So the compile
fails, and you now have new code trying to work with old format data.
The solution is to explicitly run a compile, from a properly privileged
userid, as soon as you do an RPM upgrade.
# **Why v2?**
I went onto `#perl` to ask some question about setpriority() and got yelled at
for writing "horrible code". And that was one of the kinder comments; my
rather fragile ego is trying to forget the rest ;-)
They also gave me a link to a PDF book, "Modern Perl" by 'chromatic'. Nice
book; one of the first things you learn from it is that you should not go to
`#perl` for general help.
Anyway, the summary of the collective angst of `#perl` (well 2 people anyway)
was: use Getopt::Long, FindBin, 'use lib', a library for HTTP stuff, stop
prefixing subs with '&', and get rid of the huge number of 'our' declarations.
That last item is the only one I totally agree with, because it was on my long
term todo list anyway. And 'use lib' sorta goes with it, so that's fine too.
And as soon as I found that vim colors the sub names differently if you take
out the '&' I decided I'd do that too :-) [But honestly, if `&sub` is so bad
shouldn't "man perlsub" at least say something negative about it, other than
"disables prototype checking", which doesn't matter here since I'm not using
prototypes?]
As for the rest, FindBin brings in a good 1000+ lines for something that I do
in a line or two (since I don't care about all the pathological edge cases).
Getopt::Long is 2649 lines to replace the code below [note that there *is*
only one possible option to this command, and it is *never* run manually
either, so I don't need any fancy features]:
my $shell_allowed = 0;
if (@ARGV and $ARGV[0] eq '-s') {
$shell_allowed = 1;
shift;
}
Apparently TMTOWTDI has given way to TOOWTDI.
Anyway, I spent a few hours refactoring it. And I do thank them for pushing
me to stop being lazy on the "our" business.
[gw]: https://github.com/sitaramc/gitolite/blob/pu/doc/3-faq-tips-etc.mkd#_easier_to_link_gitweb_authorisation_with_gitolite