.Dd December 15, 2019
.Dt CGIT-SETUP 7
.Os "Causal Agency"
.
.Sh NAME
.Nm cgit setup
.Nd configuration notes
.
.Sh DESCRIPTION
I just set up cgit on
.Lk https://git.causal.agency
to replace an instance of gitea.
After 30 days of uptime,
gitea had accumulated over 11 hours of CPU time
and was using hundreds of megabytes of memory.
cgit is much more lightweight
and much more in line with my aesthetic.
I'm documenting how I set it up here
mostly to remind myself in the future.
.
.Ss slowcgi
cgit is CGI software,
but
.Xr nginx 8
only supports FastCGI.
I used
.Xr slowcgi 8
as a compatibility layer
by adding the following to
.Pa /etc/rc.conf :
.Bd -literal -offset indent
slowcgi_enable="YES"
slowcgi_flags="-p / -s /var/run/slowcgi.sock"
.Ed
.
.Ss nginx
I added the following in a new
.Cm server
block to
.Pa /usr/local/etc/nginx/nginx.conf :
.Bd -literal -offset indent
root /usr/local/www/cgit;
location / {
	try_files $uri @cgit;
}
location @cgit {
	fastcgi_pass unix:/var/run/slowcgi.sock;
	fastcgi_param SCRIPT_FILENAME $document_root/cgit.cgi;
	fastcgi_param SCRIPT_NAME /;
	fastcgi_param PATH_INFO $uri;
	fastcgi_param QUERY_STRING $query_string;
	fastcgi_param REQUEST_METHOD $request_method;
	fastcgi_param CONTENT_TYPE $content_type;
	fastcgi_param CONTENT_LENGTH $content_length;
	fastcgi_param HTTPS $https if_not_empty;
	fastcgi_param SERVER_PORT $server_port;
	fastcgi_param SERVER_NAME $server_name;
}
.Ed
.
.Pp
The
.Cm try_files
directive causes
.Xr nginx 8
to first try to serve static files from
.Pa /usr/local/www/cgit
before passing anything else on to FastCGI.
.
.Pp
The
.Va SCRIPT_FILENAME
parameter tells
.Xr slowcgi 8
the path of the CGI binary to run.
Setting
.Va SCRIPT_NAME
to
.Pa /
tells cgit its root URL
and avoids it using query strings for everything.
.
.Ss cgit
cgit doesn't provide any configuration to start from,
so you have to just read
.Xr cgitrc 5 .
I added the following to
.Pa /usr/local/etc/cgitrc :
.Bd -literal -offset indent
cache-size=1024
clone-url=https://$HTTP_HOST/$CGIT_REPO_URL
snapshots=tar.gz zip
remove-suffix=1
enable-git-config=1
scan-path=/home/june/pub
.Ed
.
.Pp
The
.Cm cache-size
option enables caching,
which by default is stored in
.Pa /var/cache/cgit ,
so I made sure that directory exists
and is writable by the
.Sy www
user.
The
.Cm clone-url
option sets the clone URL to advertise.
cgit will automatically serve git over HTTP.
The
.Cm snapshots
option makes tarballs available for tags and commits.
.
.Pp
The
.Cm scan-path
option causes cgit to scan the given path
for git repositories.
I'm putting mine in
.Pa ~/pub .
The
.Cm remove-suffix
option causes cgit to remove the
.Pa .git
suffix from the URLs it uses
for the repositories it finds,
so that
.Pa ~/pub/pounce.git
is served at
.Pa /pounce .
The
.Cm enable-git-config
option allows controlling some cgit options
from the
.Xr git-config 1
of each repository.
See
.Sx git
below.
.
.Pp
I also set up a filter to render
.Xr mdoc 7
files
and do syntax highlighting
by adding the following to
.Pa cgitrc :
.Bd -literal -offset indent
readme=:README.7
readme=:README
about-filter=/usr/local/libexec/cgit-filter
source-filter=/usr/local/libexec/cgit-filter
.Ed
.
.Pp
The
.Cm readme
options tell cgit which files to look for
to render the
.Dq about
page.
The colon prefix causes it to look for them
in the git tree.
The
.Pa /usr/local/libexec/cgit-filter
script contains the following:
.Bd -literal -offset indent
#!/bin/sh
case "$1" in
	(*.[1-9])
		/usr/bin/mandoc -T utf8 | /usr/local/libexec/ttpre
		;;
	(*)
		exec /usr/local/libexec/hi -t -n "$1" -f html -o anchor
		;;
esac
.Ed
.
.Pp
Filter scripts are run with the filename as their first argument
and the contents of the file on standard input.
The
.Xr ttpre 1
command is my own utility to convert
.Xr man 1
output to HTML.
The
.Xr hi 1
command is my own
.Lk https://causal.agency/bin/hi.html "syntax highlighter" .
.
.Ss git
I create my repositories in
.Pa ~/pub
with
.Ql git init --bare
and use
.Pa git.causal.agency:pub/example.git
locally as the remote.
Descriptions are set by editing the
.Pa description
file in each repository.
The section and homepage can be set with
.Xr git-config 1
through the keys
.Cm cgit.section
and
.Cm cgit.homepage ,
respectively,
thanks to the
.Cm enable-git-config
option above.
.
.Ss Redirects
I added the following to the
.Cm server
block that used to serve gitea in
.Pa nginx.conf :
.Bd -literal -offset indent
location ~* /june/([^.]+)[.]git(.*) {
	return 301 https://git.causal.agency/$1$2?$query_string;
}
location ~* /june/([^/]+) {
	return 301 https://git.causal.agency/$1;
}
location / {
	return 301 https://git.causal.agency;
}
.Ed
.
.Pp
This redirects any links to my gitea repos
to the corresponding repo in cgit.
The first
.Sy location
block also redirects gitea HTTP clone URLs to cgit
so that
.Xr git-pull 1
continues to work on existing clones.
.
.Ss Update: fast HTTPS clones
Someone pointed out that cloning my repos
over HTTPS was incredibly slow,
and this is because cgit only implements the
.Dq dumb
HTTP git transport.
To speed up cloning,
I send the URLs used by the
.Dq smart
HTTP transport to
.Xr git-http-backend 1
instead:
.Bd -literal -offset indent
location ~ /.+/(info/refs|git-upload-pack) {
	fastcgi_pass unix:/var/run/slowcgi.sock;
	fastcgi_param SCRIPT_NAME /usr/local/libexec/git-core/git-http-backend;
	fastcgi_param GIT_HTTP_EXPORT_ALL 1;
	fastcgi_param GIT_PROJECT_ROOT /home/june/pub;
	include fastcgi_params;
}
.Ed
.
.Pp
I factored out the FastCGI parameters
I'm using with cgit
to be included here as well.
.
.Sh AUTHORS
.An June Bug Aq Mt june@causal.agency