This document is an extension of the platform-independent SCGI instructions, which may suffice for your purposes if your needs are simple.
Here, we add more detailed information on nginx itself, plus details about running it on Debian type OSes. We focus on Debian 10 (Buster) and Ubuntu 18.04 here, which are common Tier 1 OS offerings for virtual private servers. This material may not work for older OSes. It is known in particular to not work as given for Debian 9 and older!
If you want to add TLS to this configuration, that is covered in a separate document which was written with the assumption that you’ve read this first.
Benefits
This scheme is considerably more complicated than the standalone HTTP server and CGI options. Even with the benefit of this guide and pre-built binary packages, it requires quite a bit of work to set it up. Why should you put up with this complexity? Because it gives many benefits that are difficult or impossible to get with the less complicated options:
Power — nginx is one of the most powerful web servers in the world. The chance that you will run into a web serving wall that you can’t scale with nginx is very low.
To give you some idea of the sort of thing you can readily accomplish with nginx, your author runs a single public web server that provides transparent name-based virtual hosting for four separate domains:
- One is entirely static, not involving any dynamic content or Fossil integration at all.
- Another is served almost entirely by Fossil, with a few select static content exceptions punched past Fossil, which are handled entirely via nginx.
- The other two domains are aliases for one another — e.g.
example.comandexample.net— with most of the content being static. This pair of domains has three different Fossil repo proxies attached to various sections of the URI hierarchy.
By using nginx, I was able to do all of the above with minimal repetition between the site configurations.
Integration — Because nginx is so popular, it integrates with many different technologies, and many other systems integrate with it in turn. This makes it great middleware, sitting between the outer web world and interior site services like Fossil. It allows Fossil to participate seamlessly as part of a larger web stack.
Availability — nginx is already in most operating system binary package repositories, so you don’t need to go out of your way to get it.
Fossil Service Modes
Fossil provides four major ways to access a repository it’s serving remotely, three of which are straightforward to use with nginx:
HTTP — Fossil has a built-in HTTP server:
fossil server. While this method is efficient and it’s possible to use nginx to proxy access to another HTTP server, this option is overkill for our purposes. nginx is itself a fully featured HTTP server, so we will choose in this guide not to make nginx reinterpret Fossil’s implementation of HTTP.CGI — This method is simple but inefficient, because it launches a separate Fossil instance on every HTTP hit.
Since Fossil is a relatively small self-contained program, and it’s designed to start up quickly, this method can work well in a surprisingly large number of cases.
Nevertheless, we will avoid this option in this document because we’re already buying into a certain amount of complexity here in order to gain power. There’s no sense in throwing away any of that hard-won performance on CGI overhead.
SCGI — The SCGI protocol provides the simplicity of CGI without its performance problems.
SSH — This method exists primarily to avoid the need for HTTPS, but we want HTTPS. (We’ll get to that in another document.) There is probably a way to get nginx to proxy Fossil to HTTPS via SSH, but it would be pointlessly complicated.
SCGI it is, then.
Installing the Dependencies
The first step is to install some non-default packages we’ll need. SSH into your server, then say:
$ sudo apt install fossil nginx
Running Fossil in SCGI Mode
I run my Fossil SCGI server instances with a variant of the fslsrv
shell script currently hosted in the Fossil source
code repository. You’ll want to download that and make a copy of it, so
you can customize it to your particular needs.
This script allows running multiple Fossil SCGI servers, one per
repository, each bound to a different high-numbered localhost port, so
that only nginx can see and proxy them out to the public. The
“example” repo is on TCP port localhost:12345, and the “foo” repo is
on localhost:12346.
As written, the fslsrv script expects repositories to be stored in the
calling user’s home directory under ~/museum, because where else do
you keep Fossils?
That home directory also needs to have a directory to hold log files,
~/log/fossil/*.log. Fossil doesn’t put out much logging, but when it
does, it’s better to have it captured than to need to re-create the
problem after the fact.
The use of --baseurl in this script lets us have each Fossil
repository mounted in a different location in the URL scheme. Here, for
example, we’re saying that the “example” repository is hosted under
the /code URI on its domains, but that the “foo” repo is hosted at
the top level of its domain. You’ll want to do something like the
former for a Fossil repo that’s just one piece of a larger site, but the
latter for a repo that is basically the whole point of the site.
You might also want another script to automate the update, build, and deployment steps for new Fossil versions:
#!/bin/sh
cd $HOME/src/fossil/trunk
fossil up
make -j11
killall fossil
sudo make install
fslsrv
The killall fossil step is needed only on OSes that refuse to let you
replace a running binary on disk.
As written, the fslsrv script assumes a Linux environment. It expects
/bin/bash to exist, and it depends on non-POSIX tools like pgrep.
It should not be difficult to port to systems like macOS or the BSDs.
Configuration
On Debian and Ubuntu systems the primary user-level configuration file
for nginx is /etc/nginx/sites-enabled/default. I recommend that this
file contain only a list of include statements, one for each site that
server hosts:
include local/example
include local/foo
Those files then each define one domain’s configuration. Here,
/etc/nginx/local/example contains the configuration for
*.example.com and *.example.net; and local/foo contains the
configuration for *.foo.net.
The configuration for our foo.net web site, stored in
/etc/nginx/sites-enabled/local/foo is:
server {
server_name .foo.net;
include local/generic;
access_log /var/log/nginx/foo.net-https-access.log;
error_log /var/log/nginx/foo.net-https-error.log;
# Bypass Fossil for the static Doxygen docs
location /doc/html {
root /var/www/foo.net;
location ~* \.(html|ico|css|js|gif|jpg|png)$ {
expires 7d;
add_header Vary Accept-Encoding;
access_log off;
}
}
# Redirect everything else to the Fossil instance
location / {
include scgi_params;
scgi_pass 127.0.0.1:12345;
scgi_param HTTPS "on";
scgi_param SCRIPT_NAME "";
}
}
As you can see, this is a simple extension of the basic nginx service configuration for SCGI, showing off a few ideas you might want to try on your own site, such as static asset proxying.
The local/generic file referenced above helps us reduce unnecessary
repetition among the multiple sites this configuration hosts:
root /var/www/$host;
listen 80;
listen [::]:80;
charset utf-8;
There are some configuration directives that nginx refuses to substitute
variables into, citing performance considerations, so there is a limit
to how much repetition you can squeeze out this way. One such example is
the access_log and error_log directives, which follow an obvious
pattern from one host to the next. Sadly, you must tolerate some
repetition across server { } blocks when setting up multiple domains
on a single server.
The configuration for example.com and example.net is similar.
See the nginx docs for more ideas.