<title>How CGI Works In Fossil</title>
<h2>Introduction</h2><blockquote>
<p>CGI or "Common Gateway Interface" is a venerable yet reliable technique for
generating dynamic web content.  This article gives a quick background on how
CGI works and describes how Fossil can act as a CGI service.
<p>This is a "how it works" guide.  If you just want to set up Fossil
as a CGI server, see the [./server.wiki | Fossil Server Setup] page.
as a CGI server, see the [./server/ | Fossil Server Setup] page.
</blockquote>
<h2>A Quick Review Of CGI</h2><blockquote>
<p>
An HTTP request is a block of text that is sent by a client application
(usually a web browser) and arrives at the web server over a network
connection.  The HTTP request contains a URL that describes the information
being requested.  The URL in the HTTP request is typically the same URL

  *  [Wiki](./wikitheory.wiki) page changes
  *  New and edited [forum](./forum.wiki) posts
  *  Announcements

Subscribers can elect to receive emails as soon as these events happen,
or they can receive a daily digest of the events instead.

Email alerts are sent by a [Fossil server](./server.wiki), which must be
Email alerts are sent by a [Fossil server](./server/), which must be
[set up](#quick) by the Fossil administrator to send email.

Email alerts do not currently work if you are only using Fossil from the
command line.

A bit of terminology: Fossil uses the terms "email alerts" and
"notifications" interchangeably. We stick to the former term in this

render the page immediately, and will not wait for delayed scripts
to be run, thus will never enable the hyperlinks.

These two sub-settings can be used separately or together.  If used together,
then the delay timer does not start until after the first mouse movement
is detected.

See also [./server.wiki#loadmgmt|Managing Server Load] for a description
See also [./loadmgmt.md|Managing Server Load] for a description
of how expensive pages can be disabled when the server is under heavy
load.

<h2>The ongoing struggle</h2>

Fossil currently does a very good job of providing easy access to humans
while keeping out troublesome robots and spiders.  However, spiders and

Backoffice
==========

This is technical documentation about the internal workings of Fossil.
Ordinary Fossil users do not need to know about anything covered by this
document.  The information here is intended for people who want to enhance
or extend the Fossil code, or who just want a deeper understanding of
the internal workings of Fossil.

What Is The Backoffice
----------------------

The backoffice is a mechanism used by a
[Fossil server](/doc/trunk/www/server.wiki) to do low-priority
[Fossil server](./server/) to do low-priority
background work that is not directly related to the user interface.  Here
are some examples of the kinds of work that backoffice performs:

  1.  Sending email alerts and notifications
  2.  Sending out daily digests of email notifications
  3.  Other background email handling chores
  4.  Automatic syncing of peer repositories

This happens for every webpage, regardless of how that webpage is launched,
and regardless of the purpose of the webpage.  This also happens on the
server for "[fossil sync](/help?cmd=sync)" and
[fossil clone](/help?cmd=clone)" commands which are implemented as
web requests - albeit requests that the human user never sees.
Web requests can arrive at the Fossil server via direct TCP/IP (for example
when Fossil is started using commands like "[fossil server](/help?cmd=server)")
or via [CGI](/doc/trunk/www/server.wiki) or
[SCGI](/doc/trunk/www/scgi.wiki) or via SSH.
or via [CGI](./server/any/cgi.md) or
[SCGI](./server/any/scgi.md) or via SSH.
A backoffice process might be started regardless of the origin of the
request.

The backoffice is not a daemon.  Each backoffice process runs for a short
while and then exits.  This helps keep Fossil easy to manage, since there
are no daemons to start and stop.  To upgrade Fossil to a new version,
you simply replace the older "fossil" executable with the newer one, and

<title>CGI Script Configuration Options</title>

<h1>Summary</h1>

It is not necessary to have a central server in order to use Fossil.
But a central server can help a project run more smoothly by giving developers
a common point of rendezvous for syncing, and by providing a web-based
portal where developers and non-developers alike can learn about the
project and its current state.

Setting up a server using Fossil is easy.
A [./server.wiki|separate document] talks about four different methods for
setting up a Fossil server.  One of those methods, and perhaps the most
popular is [./server.wiki#cgi|CGI].  CGI is the technique that the three
A [./server/|separate document] talks about all of the many different methods for
setting up a Fossil server, one of which is [./server/any/cgi.md | as a CGI
script].  CGI is the technique that the three
[./selfhost.wiki|self-hosting Fossil repositories] all use.

Setting up a Fossil server using CGI is mostly about writing a short
script (usually just 2 lines line) in the cgi-bin folder of an ordinary
web-browser.  But there are a lot of extra options that can be added
to this script, to customize the configuration.  This article descripts
those options.

     in the thread.  Provide sequential numbers for all messages in
     a forum thread.
  *  Add support for fenced code blocks and improved hyperlink
     processing to the [/md_rules|markdown formatter].
  *  Enhance the [/help?cmd=/stat|/stat] page so that it gives the
     option to show a breakdown of forum posts.
  *  Change the default [./hashpolicy.wiki|hash policy] to SHA3.
  *  Timeout [./server.wiki#cgi|CGI requests] after 300 seconds, or 
  *  Timeout [./server/any/cgi.md|CGI requests] after 300 seconds, or 
     some other value set by the 
     [./cgi.wiki#timeout|"timeout:" property] in the CGI script.
  *  Documentation improvements

<a name='v2_9'></a>
<h2>Changes for Version 2.9 (2019-07-13)</h2>

# The Server Chroot Jail

If you run Fossil as root in any mode that [serves data on the
network][srv], and you're running it on Unix or a compatible OS, Fossil
will drop itself into a [`chroot(2)` jail][cj] shortly after starting
up, once it's done everything that requires root access. Most commonly,
you run Fossil as root to allow it to bind to TCP port 80 for HTTP
service, since normal users are restricted to ports 1024 and up on OSes
where this behavior occurs.

Fossil uses the owner of the Fossil repository file as its new user
ID when dropping root privileges.

When this happens, Fossil needs to have all of its dependencies inside
the chroot jail in order to continue work.  There are several things you
typically need in order to make things work properly:

*   the repository file(s)

*   `/dev/null` — create it with `mknod(8)` inside the jail directory
    ([Linux example][mnl])

*   `/dev/urandom` — ditto

*   `/proc` — you might need to mount this virtual filesystem inside the
    jail on Linux systems that make use of [Fossil’s server load
    shedding feature][fls]

*   any shared libraries your `fossil` binary is linked to, unless you
    [configured Fossil with `--static`][bld] to avoid it

Fossil does all of this in order to protect the host OS. You can make it
bypass the jail part of this by passing <tt>--nojail</tt> to <tt>fossil server</tt>,
but you cannot make it skip the dropping of root privileges, on purpose.


[bld]: https://www.fossil-scm.org/fossil/doc/trunk/www/build.wiki
[cj]:  https://en.wikipedia.org/wiki/Chroot
[fls]: ./loadmgmt.md
[mnl]: https://fossil-scm.org/forum/forumpost/90caff30cb
[srv]: ./server/

SCGI requests from web-servers like Nginx.

<li><p><b>Inetd or Stunnel.</b>
Configure programs like inetd, xinetd, or stunnel to hand off HTTP requests
directly to the [/help?cmd=http|fossil http] command.
</ol>

See the [./server.wiki | How To Configure A Fossil Server] document
See the [./server/ | How To Configure A Fossil Server] document
for details.

<h2>6.0 Review Of Key Concepts</h2>

<ul>
<li>The <b>fossil</b> program is a self-contained stand-alone executable.
    Just put it somewhere on your PATH to install it.</li>

For larger files, you could instead store the file in Fossil as:

*   **versioned content** retrieved via a [`/raw`](/help?cmd=/raw) URL
*   **[unversioned content](./unvers.wiki)** retrieved
    via a [`/uv`](/help?cmd=/uv) URL

Another path around this restriction is to [serve your
repo](./server.wiki) behind an HTTP proxy server, allowing mixed-mode
repo](./server/) behind an HTTP proxy server, allowing mixed-mode
content serving, with static images and such served directly by the HTTP
server and the dynamic content by Fossil. That allows a URI scheme that
prevents the browser’s CSP enforcement from distinguishing content from
Fossil proper and that from the front-end proxy.


## style-src 'self' 'unsafe-inline'

fully-independent web pages. One practical consequence of this is that
embedded <tt>&lt;script&gt;</tt> tags will cause a
[https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP | Content
Security Policy] error in your browser with the default CSP as served by
Fossil. See the documentation on [./customskin.md#headfoot | Header and
Footer Processing] and [./defcsp.md | The Default CSP].


<h2>Server-Side Text Substitution</h2>

Fossil can do a few types of substitution of server-side information
into the embedded document.

<h3>1. $ROOT</h3>

To allow for repositories [./server/ | served deeper than the root of the
URL hierarchy], Fossil can substitute the repository's root in the URL
scheme into HTML <tt>href</tt> and <tt>action</tt> attributes. For
example:

<nowiki><pre>
        [$ROOT/doc.wiki | doc at project root]
</pre></nowiki>

might become this in the rendered HTML:

<nowiki><pre>
        &lt;a href="/project/root/doc.wiki"&gt;doc at project root&lt;/a&gt;
</pre></nowiki>

As you can see, this happens for all source document types that end up
rendering as HTML, not just source documents in the HTML
<tt>fossil-doc</tt> format described at the end of the prior section.


<h3>2. TH1 Documents</h3>

Fossil will substitute the value of [./th1.md | TH1 expressions] within
<tt>{</tt> curly braces <tt>}</tt> into the output HTML if you have
configured it with the <tt>--with-th1-docs</tt> option, which is
disabled by default.


<h2>Examples</h2>

This file that you are currently reading is an example of
embedded documentation.  The name of this file in the fossil
source tree is "<b>www/embeddeddoc.wiki</b>".
You are perhaps looking at this

CGI mode.  The "index.html" CGI script looks like this:

<blockquote><pre>
#!/usr/bin/fossil
repository: /fossil/fossil.fossil
</pre></blockquote>

This is one of four ways to set up a
<a href="./server.wiki">fossil web server</a>.
This is one of the many ways to set up a
<a href="./server/">Fossil server</a>.

The "<b>/trunk/</b>" part of the URL tells fossil to use
the documentation files from the most recent trunk check-in.
If you wanted to see an historical version of this document,
you could substitute the name of a check-in for "<b>/trunk/</b>".
For example, to see the version of this document associated with
check-in [9be1b00392], simply replace the "<b>/trunk/</b>" with

If the default VFS underneath SQLite is not suitable, an alternative
can be selected with either the `--vfs VFSNAME` option or the
`FOSSIL_VFS` environment variable. The `--vfs` option takes
precedence.


### Temporary File Location
### <a name="temp"></a>Temporary File Location

Fossil places some temporary files in the checkout directory. Most notably,
supporting files related to merge conflicts are placed in the same
folder as the merge result.

Other temporary files need a different home. The rules for choosing one are
complicated.

These additional capabilities are available for Git as 3rd-party
add-ons, but with Fossil they are integrated into
the design.  One way to describe Fossil is that it is
"[https://github.com/ | GitHub]-in-a-box."

For developers who choose to self-host projects (rather than using a
3rd-party service such as GitHub) Fossil is much easier to set up, since
the stand-alone Fossil executable together with a [./server.wiki#cgi|2-line CGI script]
the stand-alone Fossil executable together with a [./server/any/cgi.md|2-line CGI script]
suffice to instantiate a full-featured developer website.  To accomplish
the same using Git requires locating, installing, configuring, integrating,
and managing a wide assortment of separate tools.  Standing up a developer
website using Fossil can be done in minutes, whereas doing the same using
Git requires hours or days.

Fossil is small, complete, and self-contained.  If you clone

      for network communications, so it works fine from behind
      restrictive firewalls, including [./quickstart.wiki#proxy|proxies].
      The protocol is
      [./stats.wiki | bandwidth efficient] to the point that Fossil can be
      used comfortably over dial-up or over the exceedingly slow Wifi on
      airliners.

  5.  <b>CGI/SCGI Enabled</b> -  No server is required, but if you want to
      set one up, Fossil supports four easy [./server.wiki | server configurations].
      You can also easily set up your server to automatically
  5.  <b>Simple Server Setup</b> -  No server is required, but if you want to
      set one up, Fossil supports [./server/ | several different server
      configurations] including CGI, SCGI, and direct HTTP.
      You can also easily set up your Fossil repository to automatically
      [./mirrortogithub.md | mirror content on GitHub].

  6.  <b>Autosync</b> -
      Fossil supports [./concepts.wiki#workflow | "autosync" mode]
      which helps to keep projects moving
      forward by reducing the amount of needless
      [./branching.wiki | forking and merging] often

     subsystems, including [./customskin.md | theming].
  *  List of [./th1.md | TH1 commands provided by Fossil itself] that expose
     its key functionality to TH1 scripts.
  *  List of [./th1-hooks.md | TH1 hooks exposed by Fossil] that enable
     customization of commands and web pages.
  *  A free hosting server for Fossil repositories is available at
     [http://chiselapp.com/].
  *  How to [./server.wiki | set up a server] for your repository.
  *  How to [./server/ | set up a server] for your repository.
  *  Customizing the [./custom_ticket.wiki | ticket system].
  *  Methods to [./checkin_names.wiki | identify a specific check-in].
  *  [./inout.wiki | Import and export] from and to Git.
  *  [./fossil-v-git.wiki | Fossil versus Git].
  *  [./fiveminutes.wiki | Up and running in 5 minutes as a single user]
     (contributed by Gilles Ganault on 2013-01-08).
  *  [./antibot.wiki | How Fossil defends against abuse by spiders and bots].

# Managing Server Load

A Fossil server is very efficient and normally presents a very light
load on the server.  The Fossil [self-hosting server][sh] is a 1/24th
slice VM at [Linode.com][lin] hosting 65 other repositories in addition
to Fossil, including some very high-traffic sites such as
<http://www.sqlite.org> and <http://system.data.sqlite.org>. This small
VM has a typical load of 0.05 to 0.1. A single HTTP request to Fossil
normally takes less than 10 milliseconds of CPU time to complete, so
requests can be arriving at a continuous rate of 20 or more per second,
and the CPU can still be mostly idle.

However, there are some Fossil web pages that can consume large amounts
of CPU time, especially on repositories with a large number of files or
with long revision histories.  High CPU usage pages include
[`/zip`](/help/zip), [`/tarball`](/help/tarball),
[`/annotate`](/help/annotate), and others.  On very large repositories,
these commands can take 15 seconds or more of CPU time.  If these kinds
of requests arrive too quickly, the load average on the server can grow
dramatically, making the server unresponsive.

Fossil provides two capabilities to help avoid server overload problems
due to excessive requests to expensive pages:

1.  An optional cache is available that remembers the 10 most recently
    requested `/zip` or `/tarball` pages and returns the precomputed
    answer if the same page is requested again.

2.  Page requests can be configured to fail with a
    “[503 Server Overload][503]” HTTP error if an expensive request is
    received while the host load average is too high.

Both of these load-control mechanisms are turned off by default, but
they are recommended for high-traffic sites.

The webpage cache is activated using the [`fossil cache
init`](/help/cache) command-line on the server.  Add a `-R` option to
specify the specific repository for which to enable caching.  If running
this command as root, be sure to “`chown`” the cache database to give
the Fossil server write permission for the user ID of the web server;
this is a separate file in the same directory and with the same name as
the repository but with the “`.fossil`” suffix changed to “`.cache`”.

To activate the server load control feature visit the Admin → Access
setup page in the administrative web interface; in the “**Server Load
Average Limit**” box enter the load average threshold above which “503
Server Overload” replies will be issued for expensive requests.  On the
self-hosting Fossil server, that value is set to 1.5, but you could
easily set it higher on a multi-core server.

The maximum load average can also be set on the command line using
commands like this:

        fossil set max-loadavg 1.5
        fossil all set max-loadavg 1.5

The second form is especially useful for changing the maximum load
average simultaneously on a large number of repositories.

Note that this load-average limiting feature is only available on
operating systems that support the [`getloadavg()`][gla] API.  Most
modern Unix systems have this interface, but Windows does not, so the
feature will not work on Windows.

Because Linux implements `getloadavg()` by accessing the `/proc/loadavg`
virtual file, you will need to make sure `/proc` is available to the
Fossil server. The most common reason for it to not be available is that
you are running a Fossil instance [inside a `chroot(2)`
jail](./chroot.md) and you have not mounted the `/proc` virtual file
system inside that jail. On the [self-hosting Fossil repositories][sh],
this was accomplished by adding a line to the `/etc/fstab` file:

        chroot_jail_proc /home/www/proc proc ro 0 0

The `/home/www/proc` pathname should be adjusted so that the `/proc`
component is at the root of the chroot jail, of course.

To see if the load-average limiter is functional, visit the
[`/test_env`][hte] page of the server to view the current load average.
If the value for the load average is greater than zero, that means that
it is possible to activate the load-average limiter on that repository.
If the load average shows exactly "0.0", then that means that Fossil is
unable to find the load average. This can either be because it is in a
`chroot(2)` jail without `/proc` access, or because it is running on a
system that does not support `getloadavg()` and so the load-average
limiter will not function.


[503]: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.4
[hte]: /help?cmd=/test_env
[gla]: https://linux.die.net/man/3/getloadavg
[lin]: http://www.linode.com
[sh]:  ./selfhost.wiki

  quickstart.wiki {Fossil Quick Start Guide}
  quotes.wiki
      {Quotes: What People Are Saying About Fossil, Git, and DVCSes in General}
  ../test/release-checklist.wiki {Pre-Release Testing Checklist}
  reviews.wiki {Reviews}
  selfcheck.wiki {Fossil Repository Integrity Self Checks}
  selfhost.wiki {Fossil Self Hosting Repositories}
  server.wiki {How To Configure A Fossil Server}
  server/ {How To Configure A Fossil Server}
  serverext.wiki {CGI Server Extensions}
  serverext.wiki {Adding Extensions To A Fossil Server Using CGI Scripts}
  settings.wiki {Fossil Settings}
  /sitemap {Site Map}
  shunning.wiki {Shunning: Deleting Content From Fossil}
  stats.wiki {Performance Statistics}
  style.wiki {Source Code Style Guidelines}

<li><a href="hashpolicy.wiki">Choosing Between SHA1 and SHA3-256 &mdash; Hash Policy:</a></li>
<li><a href="contribute.wiki">Code or Documentation To The Fossil Project &mdash; Contributing</a></li>
<li><a href="style.wiki">Code Style Guidelines &mdash; Source</a></li>
<li><a href="../../../help">Commands and Webpages &mdash; Lists of</a></li>
<li><a href="build.wiki"><b>Compiling and Installing Fossil</b></a></li>
<li><a href="concepts.wiki">Concepts &mdash; Fossil Core</a></li>
<li><a href="cgi.wiki">Configuration Options &mdash; CGI Script</a></li>
<li><a href="server.wiki">Configure A Fossil Server &mdash; How To</a></li>
<li><a href="server/">Configure A Fossil Server &mdash; How To</a></li>
<li><a href="shunning.wiki">Content From Fossil &mdash; Shunning: Deleting</a></li>
<li><a href="defcsp.md">Content Security Policy &mdash; The Default</a></li>
<li><a href="contribute.wiki"><b>Contributing Code or Documentation To The Fossil Project</b></a></li>
<li><a href="copyright-release.html"><b>Contributor License Agreement</b></a></li>
<li><a href="whyusefossil.wiki">Control &mdash; Benefits Of Version</a></li>
<li><a href="concepts.wiki">Core Concepts &mdash; Fossil</a></li>
<li><a href="newrepo.wiki">Create A New Fossil Repository &mdash; How To</a></li>

<li><a href="adding_code.wiki"><b>Hacking Fossil</b></a></li>
<li><a href="hashpolicy.wiki"><b>Hash Policy: Choosing Between SHA1 and SHA3-256</b></a></li>
<li><a href="hints.wiki">Hints &mdash; Fossil Tips And Usage</a></li>
<li><a href="index.wiki"><b>Home Page</b></a></li>
<li><a href="selfhost.wiki">Hosting Repositories &mdash; Fossil Self</a></li>
<li><a href="aboutcgi.wiki"><b>How CGI Works In Fossil</b></a></li>
<li><a href="aboutdownload.wiki"><b>How The Download Page Works</b></a></li>
<li><a href="server.wiki"><b>How To Configure A Fossil Server</b></a></li>
<li><a href="server/"><b>How To Configure A Fossil Server</b></a></li>
<li><a href="newrepo.wiki"><b>How To Create A New Fossil Repository</b></a></li>
<li><a href="mirrortogithub.md"><b>How To Mirror A Fossil Repository On GitHub</b></a></li>
<li><a href="encryptedrepos.wiki"><b>How To Use Encrypted Repositories</b></a></li>
<li><a href="hacker-howto.wiki">How-To &mdash; Hacker</a></li>
<li><a href="tls-nginx.md">HTTPS with nginx &mdash; Proxying Fossil via</a></li>
<li><a href="fossil-from-msvc.wiki">IDE &mdash; Integrating Fossil in the Microsoft Express 2010</a></li>
<li><a href="image-format-vs-repo-size.md"><b>Image Format vs Fossil Repo Size</b></a></li>

<li><a href="quotes.wiki">Saying About Fossil, Git, and DVCSes in General &mdash; Quotes: What People Are</a></li>
<li><a href="cgi.wiki">Script Configuration Options &mdash; CGI</a></li>
<li><a href="th1.md">Scripting Language &mdash; The TH1</a></li>
<li><a href="serverext.wiki">Scripts &mdash; Adding Extensions To A Fossil Server Using CGI</a></li>
<li><a href="defcsp.md">Security Policy &mdash; The Default Content</a></li>
<li><a href="selfcheck.wiki">Self Checks &mdash; Fossil Repository Integrity</a></li>
<li><a href="selfhost.wiki">Self Hosting Repositories &mdash; Fossil</a></li>
<li><a href="server.wiki">Server &mdash; How To Configure A Fossil</a></li>
<li><a href="server/">Server &mdash; How To Configure A Fossil</a></li>
<li><a href="serverext.wiki">Server Extensions &mdash; CGI</a></li>
<li><a href="serverext.wiki">Server Using CGI Scripts &mdash; Adding Extensions To A Fossil</a></li>
<li><a href="settings.wiki">Settings &mdash; Fossil</a></li>
<li><a href="admin-v-setup.md">Setup and Admin User Capabilities &mdash; The Differences Between the</a></li>
<li><a href="hashpolicy.wiki">SHA1 and SHA3-256 &mdash; Hash Policy: Choosing Between</a></li>
<li><a href="hashpolicy.wiki">SHA3-256 &mdash; Hash Policy: Choosing Between SHA1 and</a></li>
<li><a href="shunning.wiki"><b>Shunning: Deleting Content From Fossil</b></a></li>

    address only (and thus makes the web interface visible only on the
    local machine) and it automatically start your web browser pointing at the
    server.  For cross-machine collaboration, use the <b>server</b> command,
    which binds on all IP addresses and does not try to start a web browser.</p>

    <p>Servers are also easily configured as:
    <ul>
    <li>[./server.wiki#inetd|inetd/xinetd]
    <li>[./server.wiki#cgi|CGI]
    <li>[./server.wiki#scgi|SCGI]
    <li>[./server/any/inetd.md|inetd]
    <li>[./server/debian/service.md|systemd]
    <li>[./server/any/cgi.md|CGI]
    <li>[./server/any/scgi.md|SCGI]
    </ul>

    <p>The [./selfhost.wiki | self-hosting fossil repositories] use
    CGI.

<a name="proxy"></a>
<h2>HTTP Proxies</h2>

<title>How To Configure A Fossil Server</title>

<h2>No Server Required</h2>

<blockquote>
Fossil does <em>not</em> require a central server.
Data sharing and synchronization can be entirely peer-to-peer.
Fossil uses [https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type|conflict-free replicated data types]
to ensure that (in the limit) all participating peers see the exact same content.
</blockquote>

<h2>But, A Server Can Be Useful</h2>

<blockquote>
Fossil does not require a a server,
but a server does make collaboration easier.
A Fossil server also works well as a complete website for a project.
For example, the complete [https://www.fossil-scm.org/] website, including the
page you are now reading,
is just a Fossil server displaying the content of the
self-hosting repository for Fossil.

This article is a guide for setting up your own Fossil server.

See "[./aboutcgi.wiki|How CGI Works In Fossil]" for background
information on the underlying CGI technology.
See "[./sync.wiki|The Fossil Sync Protocol]" for information on the
wire protocol used for client/server communication.
</blockquote>

<h2>Overview</h2>

<blockquote>
There are basically four ways to set up a Fossil server:

<ol>
  <li>A stand-alone server
  <li>Using inetd, xinetd, or stunnel
  <li>CGI
  <li>SCGI (a.k.a. SimpleCGI)
</ol>

Each of these can serve either a single repository, or a directory hierarchy
containing many repositories with names ending in ".fossil".
</blockquote>


<h2 id="standalone">Standalone server</h2>

<blockquote>
The easiest way to set up a Fossil server is to use either the
[/help/server|server] or the [/help/ui|ui] commands:

<ul>
  <li><b>fossil server</b> <i>REPOSITORY</i>
  <li><b>fossil ui</b> <i>REPOSITORY</i>
</ul>

The <i>REPOSITORY</i> argument is either the name of the repository file, or
a directory containing many repositories named <tt>*.fossil</tt>.
Both of these commands start a Fossil server, usually on TCP port 8080, though
a higher numbered port might also be used if 8080 is already occupied.  You can
access these using URLs of the form <b>http://localhost:8080/</b>, or if
<i>REPOSITORY</i> is a directory, URLs of the form
<b>http://localhost:8080/</b><i>repo</i><b>/</b> where <i>repo</i> is the base
name of the repository file without the ".fossil" suffix.

There are several key differences between "ui" and "server":

<ul>
  <li>"ui" always binds the server to the loopback IP address
      (127.0.0.1) so that it cannot serve to other machines.
  <li>anyone who visits this URL is treated as the all-powerful Setup
      user, which is why the first difference exists.
  <li>"ui" launches a local web browser pointed at this URL.
</ul>

You can omit the <i>REPOSITORY</i> argument if you run one of the above
commands from within a Fossil checkout directory to serve that
repository:

<blockquote><pre>
$ fossil ui          # or...
$ fossil serve
</pre></blockquote>

Note that you can abbreviate Fossil sub-commands, as long as they are
unambiguous. "<tt>server</tt>" can currently be as short as
"<tt>ser</tt>".

As a more complicated example, you can serve a directory containing
multiple <tt>*.fossil</tt> files like so:

<blockquote><pre>
$ fossil server --port 9000 --repolist /path/to/repo/dir
</pre></blockquote>

There is an [/file/tools/fslsrv | example script] in the Fossil
distribution that wraps <tt>fossil server</tt> to produce more
complicated effects. Feel free to take it, study it, and modify it to
suit your local needs.

See the [/help/server|online documentation] for more information on the
options and arguments you can give to these commands.
</blockquote>


<h2 id="inetd">Fossil as an inetd/xinetd service</h2>

<blockquote>

A Fossil server can be launched on-demand by inetd or xinetd using
the [/help/http|fossil http] command. To launch Fossil from inetd, modify
your inetd configuration file (typically "/etc/inetd.conf") to contain a
line something like this:

<blockquote>
<pre>
80 stream tcp nowait.1000 root /usr/bin/fossil /usr/bin/fossil http /home/fossil/repo.fossil
</pre>
</blockquote>

In this example, you are telling "inetd" that when an incoming connection
appears on TCP port "80", that it should launch the binary "/usr/bin/fossil"
program with the arguments shown.
Obviously you will
need to modify the pathnames for your particular setup.
The final argument is either the name of the fossil repository to be served,
or a directory containing multiple repositories.


If you use a non-standard TCP port on
systems where the port-specification must be a symbolic name and cannot be
numeric, add the desired name and port to /etc/services.  For example, if
you want your Fossil server running on TCP port 12345 instead of 80, you
will need to add:

<blockquote>
<pre>
fossil          12345/tcp  #fossil server
</pre>
</blockquote>

and use the symbolic name ('fossil' in this example) instead of the numeral ('12345')
in inetd.conf. For details, see the relevant section in your system's documentation, e.g.
the [https://www.freebsd.org/doc/en/books/handbook/network-inetd.html|FreeBSD Handbook] in
case you use FreeBSD.

If your system is running xinetd, then the configuration is likely to be
in the file "/etc/xinetd.conf" or in a subfile of "/etc/xinetd.d".
An xinetd configuration file will appear like this:

<blockquote>
<pre>
service http
{
  port = 80
  socket_type = stream
  wait = no
  user = root
  server = /usr/bin/fossil
  server_args = http /home/fossil/repos/
}
</pre>
</blockquote>

The xinetd example above has Fossil configured to serve multiple
repositories, contained under the "/home/fossil/repos/" directory.

In both cases notice that Fossil was launched as root.  This is not required,
but if it is done, then Fossil will automatically put itself into a chroot
jail for the user who owns the fossil repository before reading any information
off of the wire.

Inetd or xinetd must be enabled, and must be (re)started whenever their configuration
changes - consult your system's documentation for details.

Using inetd or xinetd is a more complex setup
than the "standalone" server, but it has the
advantage of only using system resources when an actual connection is
attempted.  If no-one ever connects to that port, a Fossil server will
not (automatically) run. It has the disadvantage of requiring "root" access
and therefore may not normally be available to lower-priced "shared" servers
on the Internet.

The configuration for <tt>stunnel</tt> is similar, but it is covered in
[./ssl.wiki#stunnel|a separate document].
</blockquote>

<h2 id="cgi">Fossil as CGI</h2>

<blockquote>

A Fossil server can also be run from an ordinary web server as a CGI program.
This feature allows Fossil to be seamlessly integrated into a larger website.
CGI is how the [./selfhost.wiki | self-hosting fossil repositories] are
implemented.

To run Fossil as CGI, create a CGI script (here called "repo") in the CGI directory
of your web server and having content like this:

<blockquote><pre>
#!/usr/bin/fossil
repository: /home/fossil/repo.fossil
</pre></blockquote>

As always, adjust your paths appropriately.
It may be necessary to set permissions properly, or to modify an ".htaccess"
file or make other server-specific changes.  Consult the documentation
for your particular web server. In particular, the following permissions are
<em>normally</em> required (but, again, may be different for a particular
configuration):

<ul>
  <li>The Fossil binary (/usr/bin/fossil in the example above)
  must be readable/executable, and ALL directories leading up to it
  must be readable by the process which executes the CGI.</li>
  <li>ALL directories leading to the CGI script must also be readable and the CGI
  script itself must be executable for the user under which it will run (which often differs
  from the one running the web server - consult your site's documentation or administrator).</li>
  <li>The repository file AND the directory containing it must be writable by the same account
  which executes the Fossil binary (again, this might differ from the WWW user). The directory
  needs to be writable so that SQLite can write its journal files.</li>
  <li>Fossil must be able to create temporary files, the default directory
  for which depends on the OS.  When the CGI process is operating within
  a chroot, ensure that this directory exists and is readable/writeable
  by the user who executes the Fossil binary.</li>
</ul>

Once the script is set up correctly, and assuming your server is also set
correctly, you should be able to access your repository with a URL like:
<b>http://mydomain.org/cgi-bin/repo</b> (assuming the "repo" script is
accessible under "cgi-bin", which would be a typical deployment on Apache
for instance).

To serve multiple repositories from a directory using CGI, use the "directory:"
tag in the CGI script rather than "repository:".   You might also want to add
a "notfound:" tag to tell where to redirect if the particular repository requested
by the URL is not found:

<blockquote><pre>
#!/usr/bin/fossil
directory: /home/fossil/repos
notfound: http://url-to-go-to-if-repo-not-found/
</pre></blockquote>

Once deployed, a URL like: <b>http://mydomain.org/cgi-bin/repo/XYZ</b>
will serve up the repository "/home/fossil/repos/XYZ.fossil" (if it exists).

Additional options available to the CGI script are 
[./cgi.wiki|documented separately].

Note that Fossil itself can be launched as CGI, as described here.  But
Fossil can also launch [./serverext.wiki|sub-CGIs to implement server extensions].
Do not confuse these two concepts.  Note also that the
[./serverext.wiki|sub-CGI mechanism] works regardless of how the main
Fossil server is launched.

<h2 id="scgi">Fossil as SCGI</h2>
<blockquote>

The [/help/server|fossil server] command, described above as a way of
starting a stand-alone web server, can also be used for SCGI.  Simply add
the --scgi command-line option and the stand-alone server will interpret
and respond to the SimpleCGI or SCGI protocol rather than raw HTTP.  This can
be used in combination with a web server (such as [http://nginx.org|Nginx])
that does not support CGI.  A typical Nginx configuration to support SCGI
with Fossil would look something like this:

<blockquote><pre>
location /demo_project/ {
    include scgi_params;
    scgi_pass localhost:9000;
    scgi_param SCRIPT_NAME "/demo_project";
    scgi_param HTTPS "on";
}
</pre></blockquote>

Note that Fossil requires the SCRIPT_NAME variable
in order to function properly, but Nginx does not provide this
variable by default,
so it is necessary to provide the SCRIPT_NAME parameter in the configuration.
Failure to do this will cause Fossil to return an error.

All of the features of the stand-alone server mode described above,
such as the ability to serve a directory full of Fossil repositories
rather than just a single repository, work the same way in SCGI mode.

For security, it is probably a good idea to add the --localhost option
to the [/help/server|fossil server] command to prevent Fossil from accepting
off-site connections.  One might also want to specify the listening TCP port
number, rather than letting Fossil choose one for itself, just to avoid
ambiguity.  A typical command to start a Fossil SCGI server
would be something like this:

<blockquote><pre>
fossil server $REPOSITORY --scgi --localhost --port 9000
</pre></blockquote>
</blockquote>

<h2 id="tls">Securing a repository with TLS</h2>

<blockquote>
  Fossil's built-in HTTP server (e.g. "fossil server") does not support
  TLS, but there are multiple ways to protect your Fossil server with
  TLS. All of this is covered in a separate document, <a
  href="./ssl.wiki">Using TLS-Encrypted Communications with Fossil</a>.
</blockquote>

<h2 id="loadmgmt">Managing Server Load</h2>

<blockquote>
A Fossil server is very efficient and normally presents a very light
load on the server.
The Fossil [./selfhost.wiki | self-hosting server] is a 1/24th slice VM at
[http://www.linode.com | Linode.com] hosting 65 other repositories in
addition to Fossil (and including some very high-traffic sites such
as [http://www.sqlite.org] and [http://system.data.sqlite.org]) and
it has a typical load of 0.05 to 0.1.  A single HTTP request to Fossil
normally takes less than 10 milliseconds of CPU time to complete, so
requests can be arriving at a continuous rate of 20 or more per second,
and the CPU can still be mostly idle.

However, there are some Fossil web pages that can consume large
amounts of CPU time, especially on repositories with a large number
of files or with long revision histories.  High CPU usage pages include
[/help?cmd=/zip | /zip], [/help?cmd=/tarball | /tarball],
[/help?cmd=/annotate | /annotate] and others.  On very large repositories,
these commands can take 15 seconds or more of CPU time.
If these kinds of requests arrive too quickly, the load average on the
server can grow dramatically, making the server unresponsive.

Fossil provides two capabilities to help avoid server overload problems
due to excessive requests to expensive pages:

<ol>
  <li><p>An optional cache is available that remembers the 10 most recently
      requested /zip or /tarball pages and returns the precomputed answer
      if the same page is requested again.</p>
  <li><p>Page requests can be configured to fail with a
      [http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.4 | "503 Server Overload"]
      HTTP error if an expensive request is received while the host load
      average is too high.</p>
</ol>

Both of these load-control mechanisms are turned off by default, but they
are recommended for high-traffic sites.

The webpage cache is activated using the [/help?cmd=cache|fossil cache init]
command-line on the server.  Add a -R option to specify the specific repository
for which to enable caching.  If running this command as root, be sure to
"chown" the cache database (which is a separate file in the same directory
and with the same name as the repository but with the suffix changed to ".cache")
to give it write permission for the userid of the web server.

To activate the server load control feature
visit the Admin → Access setup page in the administrative web
interface; in the "<b>Server Load Average Limit</b>" box
enter the load average threshold above which "503 Server
Overload" replies will be issued for expensive requests.  On the
self-hosting Fossil server, that value is set to 1.5, but you could easily
set it higher on a multi-core server.

The maximum load average can also be set on the command line using
commands like this:
<blockquote><pre>
fossil set max-loadavg 1.5
fossil all set max-loadavg 1.5
</pre></blockquote>

The second form is especially useful for changing the maximum load average
simultaneously on a large number of repositories.

Note that this load-average limiting feature is only available on operating
systems that support the "getloadavg()" API.  Most modern Unix systems have
this interface, but Windows does not, so the feature will not work on Windows.
Note also that Linux implements "getloadavg()" by accessing the "/proc/loadavg"
file in the "proc" virtual file system.  If you are running a Fossil instance
inside a chroot() jail on Linux, you will need to make the "/proc" file
system available inside that jail in order for this feature to work.  On
the [./selfhost.wiki|self-hosting Fossil repositories], this was accomplished
by adding a line to the "/etc/fstab" file that looks like:

<blockquote><pre>
chroot_jail_proc /home/www/proc proc ro 0 0
</pre></blockquote>

The /home/www/proc pathname should be adjusted so that the "/proc" component is
in the root of the chroot jail, of course.

To see if the load-average limiter is functional, visit the [/test_env] page
of the server to view the current load average.  If the value for the load
average is greater than zero, that means that it is possible to activate
the load-average limiter on that repository.  If the load average shows
exactly "0.0", then that means that Fossil is unable to find the load average
(either because it is in a chroot() jail without /proc access, or because
it is running on a system that does not support "getloadavg()") and so the
load-average limiter will not function.

</blockquote>

# Serving via althttpd

The public SQLite and Fossil web sites are not purely served by Fossil
for two reasons:

1.  We want access to these sites to be secured with TLS, which we do
    [via `stunnel`](./stunnel.md).

2.  Parts of these web sites are static, stored as plain files on disk,
    not as Fossil artifacts. We serve such files using a separate web
    server called [`althttpd`][ah], written by the primary author of
    both SQLite and Fossil, D. Richard Hipp. `althttpd` is a lightweight
    HTTP-only web server. It handles the static HTTP hits on
    <tt>sqlite.org</tt> and <tt>fossil-scm.org</tt>, delegating HTTPS
    hits to `stunnel` and dynamic content hits to Fossil [via
    CGI][cgi].

The largest single chunk of static content served directly by `althttpd`
rather than via Fossil is the [SQLite documentation][sd], which is built
[from source files][ds]. We don’t want those output files stored in
Fossil; we already keep that process’s *input* files in Fossil. Thus the
choice to serve the output statically.

In addition to the [server’s documentation page][ah], there is a large,
helpful header comment in the server’s [single-file C
implementation][ac]. Between that and the generic [Serving via CGI][cgi]
docs, you should be able to figure out how to serve Fossil via
`althttpd`.

*[Return to the top-level Fossil server article.](../)*


[ac]:  https://sqlite.org/docsrc/file/misc/althttpd.c
[ah]:  https://sqlite.org/docsrc/doc/trunk/misc/althttpd.md
[cgi]: ./cgi.md
[ds]:  https://sqlite.org/docsrc/
[sd]:  https://sqlite.org/docs.html

# Serving via CGI

A Fossil server can be run from most ordinary web servers as a CGI
program.  This feature allows Fossil to seamlessly integrate into a
larger website.  We use CGI for the [self-hosting Fossil repository web
site](../../selfhost.wiki).

To run Fossil as CGI, create a CGI script (here called "repo") in the
CGI directory of your web server with content like this:

        #!/usr/bin/fossil
        repository: /home/fossil/repo.fossil

Adjust the paths appropriately.  It may be necessary to set certain
permissions on this file or to modify an `.htaccess` file or make other
server-specific changes.  Consult the documentation for your particular
web server. The following permissions are *normally* required, but,
again, may be different for a particular configuration:

*   The Fossil binary (`/usr/bin/fossil` in the example above)
    must be readable/executable.

*   *All* directories leading up to the Fossil binary must be readable
    by the process which executes the CGI.

*   The CGI script must be executable for the user under which it will
    run, which often differs from the one running the web server.
    Consult your site's documentation or the web server’s system
    administrator.

*   *All* directories leading to the CGI script must be readable by the
    web server.

*   The repository file *and* the directory containing it must be
    writable by the same account which executes the Fossil binary.
    (This might differ from the user the web server normally runs
    under.) The directory holding the repository file(s) needs to be
    writable so that SQLite can write its journal files.

*   Fossil must be able to create temporary files in a
    [directory that varies by host OS](../../env-opts.md#temp). When the
    CGI process is operating [within a chroot](../../chroot.md),
    ensure that this directory exists and is readable/writeable by the
    user who executes the Fossil binary.

Once the CGI script is set up correctly, and assuming your server is
also set correctly, you should be able to access your repository with a
URL like: <b>http://mydomain.org/cgi-bin/repo</b> This is assuming you
are running a web server like Apache that uses a “`cgi-bin`” directory
for scripts like our “`repo`” example.

To serve multiple repositories from a directory using CGI, use the
"directory:" tag in the CGI script rather than "repository:".  You
might also want to add a "notfound:" tag to tell where to redirect if
the particular repository requested by the URL is not found:

        #!/usr/bin/fossil
        directory: /home/fossil/repos
        notfound: http://url-to-go-to-if-repo-not-found/

Once deployed, a URL like: <b>http://mydomain.org/cgi-bin/repo/XYZ</b>
will serve up the repository `/home/fossil/repos/XYZ.fossil` if it
exists.

Additional options available to the CGI script are [documented
separately](../../cgi.wiki).

*[Return to the top-level Fossil server article.](../)*

# Serving via inetd

A Fossil server can be launched on-demand by `inetd` by  using the
[`fossil http`](/help/http) command. To do so, add a line like the
following to its configuration file, typically `/etc/inetd.conf`:

        80 stream tcp nowait.1000 root /usr/bin/fossil /usr/bin/fossil http /home/fossil/repo.fossil

In this example, you are telling `inetd` that when an incoming
connection appears on TCP port 80 that it should launch the program
`/usr/bin/fossil` with the arguments shown.  Obviously you will need to
modify the pathnames for your particular setup.  The final argument is
either the name of the fossil repository to be served or a directory
containing multiple repositories.

If you use a non-standard TCP port on systems where the port
specification must be a symbolic name and cannot be numeric, add the
desired name and port to `/etc/services`.  For example, if you want your
Fossil server running on TCP port 12345 instead of 80, you will need to
add:

        fossil          12345/tcp  # fossil server

and use the symbolic name “`fossil`” instead of the numeric TCP port
number (“12345” in the above example) in `inetd.conf`.

Notice that we configured `inetd` to launch Fossil as root. See the
top-level section on “[The Fossil Chroot
Jail](../../chroot.md)” for the consequences of this and
alternatives to it.

You can instead configure `inetd` to bind to a higher-numbered TCP port,
allowing Fossil to be run as a normal user. In that case, Fossil will
not put itself into a chroot jail, because it assumes you have set up
file permissions and such on the server appropriate for that user.

The `inetd` daemon must be enabled for this to work, and it must be
restarted whenever its configuration file changes.

This is a more complicated method than the [standalone HTTP server
method](./none.md), but it has the advantage of only using system
resources when an actual connection is attempted.  If no one ever
connects to that port, a Fossil server will not (automatically) run. It
has the disadvantage of requiring "root" access, which may not be
available to you, either due to local IT policy or because of
restrictions at your shared Internet hosting service.

For further details, see the relevant section in your system's
documentation. The FreeBSD Handbook covers `inetd` in [this
chapter](https://www.freebsd.org/doc/en/books/handbook/network-inetd.html).

*[Return to the top-level Fossil server article.](../)*

# Standalone HTTP Server

The easiest way to set up a Fossil server is to use either the
[`server`](/help/server) or [`ui`](/help/ui) command:

*  **fossil server** _REPOSITORY_
*  **fossil ui** _REPOSITORY_

The _REPOSITORY_ argument is either the name of the repository file or a
directory containing many repositories named “`*.fossil`”.  Both of these
commands start a Fossil server, usually on TCP port 8080, though a
higher numbered port will be used instead if 8080 is already occupied.

You can access these using URLs of the form **http://localhost:8080/**,
or if _REPOSITORY_ is a directory, URLs of the form
**http://localhost:8080/**_repo_**/** where _repo_ is the base name of
the repository file without the “`.fossil`” suffix.

There are several key differences between “`ui`” and “`server`”:

*   “`ui`” always binds the server to the loopback IP address (127.0.0.1)
    so that it cannot serve to other machines.

*   Anyone who visits this URL is treated as the all-powerful Setup
    user, which is why the first difference exists.
  
*   “`ui`” launches a local web browser pointed at this URL.

You can omit the _REPOSITORY_ argument if you run one of the above
commands from within a Fossil checkout directory to serve that
repository:

        $ fossil ui          # or...
        $ fossil server

You can abbreviate Fossil sub-commands as long as they are unambiguous.
“`server`” can currently be as short as “`ser`”.

You can serve a directory containing multiple `*.fossil` files like so:

        $ fossil server --port 9000 --repolist /path/to/repo/dir

There is an [example script](/file/tools/fslsrv) in the Fossil
distribution that wraps `fossil server` to produce more complicated
effects. Feel free to take it, study it, and modify it to suit your
local needs.

See the [online documentation](/help/server) for more information on the
options and arguments you can give to these commands.

*[Return to the top-level Fossil server article.](../)*

# Serving via SCGI

There is an alternative to running Fossil as a [standalone HTTP
server](./none.md), which is to run it in SimpleCGI (a.k.a. SCGI) mode,
which uses the same [`fossil server`](/help/server) command as for HTTP
service. Simply add the `--scgi` command-line option and the stand-alone
server will speak the SCGI protocol rather than raw HTTP.

This can be used with a web server such as [nginx](http://nginx.org)
which does not support [Fossil’s CGI mode](./cgi.md).

A basic nginx configuration to support SCGI with Fossil looks like this:

        location /example/ {
            include scgi_params;
            scgi_pass localhost:9000;
            scgi_param SCRIPT_NAME "/example";
            scgi_param HTTPS "on";
        }

Start Fossil so that it will respond to nginx’s SCGI calls like this:

        fossil server /path/to/repo.fossil --scgi --localhost --port 9000

The `--scgi` option switches Fossil into SCGI mode from its default,
which is [stand-alone HTTP server mode](./none.md). All of the other
options discussed in that linked document — such as the ability to serve
a directory full of Fossil repositories rather than just a single
repository — work the same way in SCGI mode.

The `--localhost` option is simply good security: we’re using nginx to
expose Fossil service to the outside world, so there is no good reason
to allow outsiders to contact this Fossil SCGI server directly.

Giving an explicit non-default TCP port number via `--port` is a good
idea to avoid conflicts with use of Fossil’s default TCP service port,
8080, which may conflict with local uses of `fossil ui` and such.

Fossil requires the `SCRIPT_NAME` environment variable in order to
function properly, but nginx does not provide this variable by default,
so it is necessary to provide it in the configuration.  Failure to do
this will cause Fossil to return an error.

The [example `fslsrv` script](/file/tools/fslsrv) shows off these same
concepts in a more complicated setting. You might want to mine that
script for ideas.

You might want to next read one of the platform-specific versions of this
document, which goes into more detail:

*   [Debian/Ubuntu](../debian/nginx.md)

There is a [separate article](../../tls-nginx.md) showing how to add TLS
encryption to this basic SCGI + nginx setup.

*[Return to the top-level Fossil server article.](../)*

# Serving via stunnel

[`stunnel`](https://www.stunnel.org/) is a TLS/SSL proxy for programs
that themselves serve only via HTTP, such as Fossil. (Fossil *can* speak
HTTPS, but only as a client.) `stunnel` decodes the HTTPS data from the
outside world as HTTP before passing it to Fossil, and it encodes the
HTTP replies from Fossil as HTTPS before sending them to the remote host
that made the request.

You can run `stunnel` in one of two modes: socket listener — much like
in our [`inetd` doc](./inetd.md) — and as an HTTP reverse proxy. We’ll
cover both cases here, separately.


## S<a name="sa"></a>ocket Activation

The following `stunnel.conf` configuration configures it to run Fossil
in socket listener mode, launching Fossil only when an HTTPS hit comes
in, then shutting it back down as soon as the transaction is complete:

```dosini
    [fossil]
    accept       = 443
    TIMEOUTclose = 0
    exec         = /usr/bin/fossil
    execargs     = /usr/bin/fossil http /home/fossil/ubercool.fossil --https
    cert         = /etc/letsencrypt/live/ubercool-project.org/fullchain.pem
    key          = /etc/letsencrypt/live/ubercool-project.org/privkey.pem
    ciphers      = ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:AES256-GCM-SHA384:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES128-SHA:DES-CBC3-SHA
    options      = CIPHER_SERVER_PREFERENCE
```

This configuration shows the TLS certificate generated by the [Let’s
Encrypt](https://letsencrypt.org) [Certbot](https://certbot.eff.org) in
[certonly mode](https://certbot.eff.org/lets-encrypt/debianbuster-other).
There are other ways to get TLS certificates, but this is a popular and
free option.

You will need to adjust the site names and paths in this example. Where
this file goes varies by OS type, so check the man pages on your system
to find out where it should be locally.

See the `stunnel` documentation for further details about this
configuration file.

It is important that the [`fossil http`](/help/http) command in that
configuration include the `--https` option to let Fossil know to use
“`https://`” instead of “`http://`” in generated hyperlinks.



## <a name="proxy"></a>Reverse Proxy

You can instead have Fossil running in the background in [standalone
HTTP server mode](./none.md), bound to a high random TCP port number on
localhost via the `--localhost` and `--port` flags, then configure
`stunnel` to reverse proxy public HTTPS connections down to it via HTTP.

The configuration is the same as the above except that you drop the
`exec` and `execargs` directives and add this instead:

```dosini
    connect      = 9000
```

That tells `stunnel` to connect to an already-running process listening
on the given TCP port number.

There are a few advantages to this mode:

1.  At the cost of some server memory and a tiny bit of idle CPU time,
    Fossil remains running so that hits can be served a smidge faster
    than in socket listener mode, where the Fossil binary has to be
    loaded and re-initialized on each HTTPS hit.

2.  The socket listener mode doesn’t work on all platforms that
    `stunnel` runs on, particularly [on Windows](../windows/stunnel.md).

*[Return to the top-level Fossil server article.](../)*

# Serving via xinetd

Some operating systems have replaced the old Unix `inetd` daemon with
`xinetd`, which has a similar mission but with a very different
configuration file format.

The typical configuration file is either `/etc/xinetd.conf` or a subfile
in the `/etc/xinetd.d` directory. You need a configuration something
like this for Fossil:

        service http
        {
          port = 80
          socket_type = stream
          wait = no
          user = root
          server = /usr/bin/fossil
          server_args = http /home/fossil/repos/
        }

This example configures Fossil to serve multiple repositories under the
`/home/fossil/repos/` directory.

Beyond this, see the general commentary in our article on [the `inetd`
method](./inetd.md) as they also apply to service via `xinetd`.

*[Return to the top-level Fossil server article.](../)*

# Serving via nginx on Debian and Ubuntu

This document is an extension of [the platform-independent SCGI
instructions][scgii], 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][vps].  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][tls] which was written with the assumption that
you’ve read this first.

[scgii]: ../any/scgi.md
[tls]:   ../../tls-nginx.md
[vps]:   https://en.wikipedia.org/wiki/Virtual_private_server


## <a name="benefits"></a>Benefits

This scheme is considerably more complicated than the [standalone HTTP
server](../any/none.md) and [CGI options](../any/cgi.md). 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.com` and `example.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.


## <a name="modes"></a>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`](/help/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][scgip] 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][tls].)
    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.

[scgip]: https://en.wikipedia.org/wiki/Simple_Common_Gateway_Interface


## <a name="deps"></a>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


## <a name="scgi"></a>Running Fossil in SCGI Mode

I run my Fossil SCGI server instances with a variant of [the `fslsrv`
shell script](/file/tools/fslsrv) 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.


## <a name="config"></a>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][scgii], 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](http://nginx.org/en/docs/) for more ideas.

*[Return to the top-level Fossil server article.](../)*

# Serving via systemd on Debian and Ubuntu

[`systemd`][sdhome] is the default service management framework on
Debian [since version 8][wpa] and Ubuntu since version 15.04, both
released in April 2015.

There are multiple ways to get a service to launch under `systemd`.
We’re going to show two methods which correspond approximately to two of
our generic Fossil server setup methods, the [`inetd`](../any/inetd.md)
and [standalone HTTP server](../any/none.md) methods.

[sdhome]: https://www.freedesktop.org/wiki/Software/systemd/
[wpa]:    https://en.wikipedia.org/wiki/Systemd#Adoption



## User Service

A fun thing you can easily do with `systemd` that you can’t directly do
with older technologies like `inetd` and `xinetd` is to set a server up
as a “user” service.

You can’t listen on TCP port 80 with this method due to security
restrictions on TCP ports in every OS where `systemd` runs, but you can
create a listener socket on a high-numbered (≥ 1024) TCP port,
suitable for sharing a Fossil repo to a workgroup on a private LAN.

To do this, write the following in
`~/.local/share/systemd/user/fossil.service`:

```dosini
    [Unit]
    Description=Fossil user server
    After=network.target

    [Service]
    WorkingDirectory=/home/fossil/museum
    ExecStart=/home/fossil/bin/fossil server --port 9000 repo.fossil
    Restart=always
    RestartSec=3

    [Install]
    WantedBy=sockets.target
    WantedBy=multi-user.target
```

Unlike with `inetd` and `xinetd`, we don’t need to tell `systemd` which
user and group to run this service as, because we’ve installed it as a
user service under the account we’re logged into.

We’ve told `systemd` that we want automatic service restarts with
back-off logic, making this much more robust than the by-hand launches
of `fossil` in the platform-independent Fossil server instructions.  The
service will stay up until we explicitly tell it to shut down.

Because we’ve set this up as a user service, the commands you give to
manipulate the service vary somewhat from the sort you’re more likely to
find online:

        $ systemctl --user daemon-reload
        $ systemctl --user enable fossil
        $ systemctl --user start fossil
        $ systemctl --user status -l fossil
        $ systemctl --user stop fossil

That is, we don’t need to talk to `systemd` with `sudo` privileges, but
we do need to tell it to look at the user configuration rather than the
system-level configuration.

This scheme isolates the permissions needed by the Fossil server, which
reduces the amount of damage it can do if there is ever a
remotely-triggerable security flaw found in Fossil.

A simple and useful modification to the above scheme is to add the
`--scgi` and `--localhost` flags to the `ExecStart` line to replace the
use of `fslsrv` in [the generic SCGI instructions](../any/scgi.md),
giving a much more robust configuration.


## Socket Activation

Another useful method to serve a Fossil repo via `systemd` is via a
socket listener, which `systemd` calls “[socket activation][sa].”
It’s more complicated, but it has some nice properties.  It is the
feature that allows `systemd` to replace `inetd`, `xinetd`, Upstart, and
several other competing technologies.

We first need to define the privileged socket listener by writing
`/etc/systemd/system/fossil.socket`:

```dosini
    [Unit]
    Description=Fossil socket

    [Socket]
    Accept=yes
    ListenStream=80
    NoDelay=true

    [Install]
    WantedBy=sockets.target
```

Note the change of configuration directory from the `~/.local` directory
to the system level. We need to start this socket listener at the root
level because of the low-numbered TCP port restriction we brought up
above.

This configuration says more or less the same thing as the socket part
of an `inted` entry [exemplified elsewhere in this
documentation](../any/inetd.md).

Next, create the service definition file in that same directory as
`fossil@.service`:

```dosini
    [Unit]
    Description=Fossil socket server
    After=network.target

    [Service]
    WorkingDirectory=/home/fossil/museum
    ExecStart=/home/fossil/bin/fossil http repo.fossil
    StandardInput=socket

    [Install]
    WantedBy=sockets.target
    WantedBy=multi-user.target
```

We’ll explain the “`@`” in the file name below.

Notice that we haven’t told `systemd` which user and group to run Fossil
under. Since this is a system-level service definition, that means it
will run as root, which then causes Fossil to [automatically drop into a
`chroot(2)` jail](../../chroot.md) rooted at the `WorkingDirectory`
we’ve configured above, shortly each `fossil http` call starts.

The `Restart*` directives we had in the user service configuration above
are unnecessary for this method, since Fossil isn’t supposed to remain
running under it. Each HTTP hit starts one Fossil instance, which
handles that single client’s request and then immediately shuts down.

Next, you need to tell `systemd` to reload its system-level
configuration files and enable the listening socket:

        $ sudo systemctl daemon-reload
        $ sudo systemctl enable fossil.socket

And now you can manipulate the socket listener:

        $ sudo systemctl start fossil.socket
        $ sudo systemctl status -l fossil.socket
        $ sudo systemctl stop fossil.socket

Notice that we’re working with the *socket*, not the *service*. The fact
that we’ve given them the same base name and marked the service as an
instantiated service with the “`@`” notation allows `systemd` to
automatically start an instance of the service each time a hit comes in
on the socket that `systemd` is monitoring on Fossil’s behalf. To see
this service instantiation at work, visit a long-running Fossil page
(e.g. `/tarball`) and then give a command like this:

        $ sudo systemctl --full | grep fossil

This will show information about the `fossil` socket and service
instances, which should show your `/tarball` hit handler, if it’s still
running:

        fossil@20-127.0.0.1:80-127.0.0.1:38304.service

You can feed that service instance description to a `systemctl kill`
command to stop that single instance without restarting the whole
`fossil` service, for example.

In all of this, realize that we’re able to manipulate a single socket
listener or single service instance at a time, rather than reload the
whole externally-facing network configuration as with the far more
primitive `inetd` service.

[sa]: http://0pointer.de/blog/projects/socket-activation.html


*[Return to the top-level Fossil server article.](../)*

<div class='fossil-doc' data-title="How To Configure A Fossil Server">

<style type="text/css">
  p {
    margin-left: 4em;
    margin-right: 3em;
  }

  h2 {
    margin-left: 1em;
  }

  h3 {
    margin-left: 3em;
  }

  ol, ul {
    margin-left: 3em;
  }

  a#all {
    font-size: 90%;
    margin-left: 1em;
  }

  div#tutpick.show {
    max-height: 99em;
    transition: max-height 1000ms ease-in;
  }
  div#tutpick {
    max-height: 0;
    overflow: hidden;
  }

  th.fep {
    background-color: #e8e8e8;
    min-width: 3em;
    padding: 0.4em;
    white-space: nowrap;
  }

  th.host {
    background-color: #e8e8e8;
    padding: 0.4em;
    text-align: right;
  }

  td.doc {
    text-align: center;
  }
</style>


<h2>No Server Required</h2>

<p>Fossil does not require a central server, but <a
href="whyuseaserver.wiki">a server can be very useful</a>.</p>

<p>This article is a quick-reference guide for setting up your own
Fossil server, with links to more detailed instructions specific to
particular systems, should you want extra help.</p>


<h2 id="methods">Methods</h2>

<p>There are basically four ways to set up a Fossil server:</p>

<ol>
  <li><a id="cgi"        href="any/cgi.md">CGI</a>
  <li><a id="standalone" href="any/none.md">Stand-alone HTTP server</a>
  <li>Socket listener
  <li><a id="scgi"       href="any/scgi.md">SCGI</a>
</ol>

<p>All of these methods can serve either a single repository or a
directory containing repositories named "<tt>*.fossil</tt>".</p>

<p>You are not restricted to using a single method. The same Fossil
repository can be served using two or more of the above techniques at
the same time. These methods use clean, well-defined, standard
interfaces (CGI, SCGI, and HTTP) which allow you to easily migrate from
one method to another to accommodate changes in hosting providers or
administrator preferences.</p>

<h3>CGI</h3>

<p>Most ordinary web servers can <a href="any/cgi.md">run Fossil as a
CGI script</a>. This method is known to work with Apache,
<tt>lighttpd</tt>, and <a
href="any/althttpd.md"><tt>althttpd</tt></a>.  The Fossil server
administrator places a <a href="/help?cmd=cgi">short CGI script</a> in
the web server's document hierarchy, and when a client requests the
appropriate URL, that script runs Fossil to generate the response.</p>

<p>CGI is a good choice for merging Fossil into an existing web site,
particularly on hosts that have CGI set up for you already and won't let
you modify the web server configuration further. The Fossil <a
href="../selfhost.wiki">self-hosting repositories</a> are implemented
with CGI underneath <tt>althttpd</tt>.</p>

<h3>Stand-alone HTTP Server</h3>

<p>This is the <a href="any/none.md">easiest method</a>.
A stand-alone server uses the <a
href="/help?cmd=server"><tt>fossil server</tt></a> command to run a
process that listens for incoming HTTP requests on a socket and then
dispatches a copy of itself to deal with each incoming request. You can
expose Fossil directly to the clients in this way or you can interpose a
<a href="https://en.wikipedia.org/wiki/Reverse_proxy">reverse proxy</a>
layer between the clients and Fossil.</p>

<h3>Socket Listener</h3>

<p>Only slightly more complicated is the socket listener method.
Instead of letting Fossil run in the background continuously to handle
HTTP requests from clients, you configure a socket listener daemon to
run a <a href="/help?cmd=http"><tt>fossil http</tt></a> command on each
HTTP hit.  That Fossil instance handles only that one hit and then shuts
back down, letting the socket listener go back to waiting for the next
hit.  This scheme is known to work with <a id="inetd"
href="any/inetd.md"><tt>inetd</tt></a>, <a id="xinetd"
href="any/xinetd.md"><tt>xinetd</tt></a>, <a id="stunnel"
href="any/stunnel.md"><tt>stunnel</tt></a>, <a
href="macos/service.md"><tt>launchd</tt></a>, and <a
href="debian/service.md"><tt>systemd</tt></a>.</p>

<h3>SCGI</h3>

<p>The Fossil standalone server can also run <a href="any/scgi.md">in
SCGI mode</a> — <a href="/help/server"><tt>fossil server --scgi</tt></a>
— instead of <a href="any/none.md">HTTP mode</a>, which allows it to
respond to requests from web servers <a href="debian/nginx.md">such as
nginx</a> that don't support CGI. SCGI is a simpler protocol to proxy
than HTTP, since the HTTP doesn't have to be re-interpreted in terms of
the proxy's existing HTTP implementation, but it's more complex to set
up because you also have to set up an SCGI-to-HTTP proxy for it. It is
worth taking on this difficulty only when you need to integrate Fossil
into an existing web site already being served by an SCGI-capable web
server.</p>

<h2 id="matrix">Setup Tutorials</h2>

<p>We've broken the configuration for each method out into a series of
sub-articles. Some of these are generic, while others depend on
particular operating systems or front-end software:</p>

<div id="tutpick" class="show"></div>

<table style="margin-left: 6em;">
    <tr>
        <th class="host">⇩ OS / Method ⇨</th>
        <th class="fep">direct</th>
        <th class="fep">inetd</th>
        <th class="fep">stunnel</th>
        <th class="fep">CGI</th>
        <th class="fep">SCGI</th>
        <th class="fep">althttpd</th>
        <th class="fep">proxy</th>
        <th class="fep">service</th>
    </tr>

    <tr>
        <th class="host">Any</th>
        <td class="doc"><a href="any/none.md">✅</a></td>
        <td class="doc"><a href="any/inetd.md">✅</a></td>
        <td class="doc"><a href="any/stunnel.md">✅</a></td>
        <td class="doc"><a href="any/cgi.md">✅</a></td>
        <td class="doc"><a href="any/scgi.md">✅</a></td>
        <td class="doc"><a href="any/althttpd.md">✅</a></td>
        <td class="doc">❌</td>
        <td class="doc">❌</td>
    </tr>

    <tr>
        <th class="host">Debian/Ubuntu</th>
        <td class="doc"><a href="any/none.md">✅</a></td>
        <td class="doc"><a href="any/inetd.md">✅</a></td>
        <td class="doc"><a href="any/stunnel.md">✅</a></td>
        <td class="doc"><a href="any/cgi.md">✅</a></td>
        <td class="doc"><a href="any/scgi.md">✅</a></td>
        <td class="doc"><a href="any/althttpd.md">✅</a></td>
        <td class="doc"><a href="debian/nginx.md">✅</a></td>
        <td class="doc"><a href="debian/service.md">✅</a></td>
    </tr>

    <tr>
        <th class="host">macOS</th>
        <td class="doc"><a href="any/none.md">✅</a></td>
        <td class="doc">❌</td>
        <td class="doc"><a href="any/stunnel.md">✅</a></td>
        <td class="doc"><a href="any/cgi.md">✅</a></td>
        <td class="doc"><a href="any/scgi.md">✅</a></td>
        <td class="doc"><a href="any/althttpd.md">✅</a></td>
        <td class="doc">❌</td>
        <td class="doc"><a href="macos/service.md">✅</a></td>
    </tr>

    <tr>
        <th class="host">Windows</th>
        <td class="doc"><a href="windows/none.md">✅</a></td>
        <td class="doc">❌</td>
        <td class="doc"><a href="windows/stunnel.md">✅</a></td>
        <td class="doc"><a href="windows/cgi.md">✅</a></td>
        <td class="doc">❌</td>
        <td class="doc">❌</td>
        <td class="doc"><a href="windows/iis.md">✅</a></td>
        <td class="doc"><a href="windows/service.md">✅</a></td>
    </tr>
</table>

<p>Where there is a check mark in the "<b>Any</b>" row, the method for that is
generic enough that it works across OSes that Fossil is known to work
on. The check marks below that usually just link to this generic
documentation.</p>

<p>The method in the "<b>proxy</b>" column is for the platform's default
web server configured as a <a
href="https://en.wikipedia.org/wiki/Reverse_proxy">reverse proxy</a> for
Fossil's built-in HTTP server: <a href="debian/nginx.md">nginx</a>, <a
href="windows/iis.md">IIS</a>, Apache, etc.</p>

<p>We welcome <a href="../contribute.wiki">contributions</a> to fill gaps
(<font size="-2">❌</font>) in the table above.</p>
</noscript>


<h2 id="more">Further Details</h2>

<ul>
  <li><a id="chroot"   href="../chroot.md"     >The Server Chroot Jail</a>
  <li><a id="loadmgmt" href="../loadmgmt.md"   >Managing Server Load</a>
  <li><a id="tls"      href="../ssl.wiki"      >Securing a Repository with TLS</a>
  <li><a id="ext"      href="../serverext.wiki">CGI Server Extensions</a>
  <li><a id="about"    href="../aboutcgi.wiki" >How CGI Works In Fossil</a>
  <li><a id="sync"     href="../sync.wiki"     >The Fossil Sync Protocol</a>
</ul>

</div>

# Serving via launchd on macOS

[`launchd`][ldhome] is the default service management framework on macOS
[since the release of Tiger in 2005][wpa]. If you want a Fossil server
to launch in the background on a Mac, it’s the way Apple wants you to do
it. `launchd` is to macOS as `systemd` is to most modern Linux desktop
systems. (Indeed, `systemd` arguably reinvented the perfectly good,
pre-existing `launchd` wheel.)

Unlike in [our `systemd` article](../debian/service.md), we’re not going
to show the per-user method here, because those so-called
[LaunchAgents][la] only start when a user is logged into the GUI, and
they stop when that user logs out. This does not strike us as proper
“server” behavior, so we’ll stick to system-level LaunchDaemons instead.

However, we will still give two different configurations, just as in the
`systemd` article: one for a standalone HTTP server, and one using
socket activation.

For more information on `launchd`, the single best resource we’ve found
is [](launchd.info). The next best is:

        $ man launchd.plist

[la]:     http://www.grivet-tools.com/blog/2014/launchdaemons-vs-launchagents/
[ldhome]: https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPSystemStartup/Chapters/CreatingLaunchdJobs.html
[wpa]:    https://en.wikipedia.org/wiki/Launchd



## Standalone HTTP Server

To configure `launchd` to start Fossil as a standalone HTTP server,
write the following as `com.example.dev.FossilHTTP.plist`:

```xml
    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
    <plist version="1.0">
    <dict>
        <key>Label</key>
        <string>com.example.dev.FossilHTTP</string>
        <key>ProgramArguments</key>
        <array>
            <string>/usr/local/bin/fossil</string>
            <string>server</string>
            <string>--port</string>
            <string>9000</string>
            <string>repo.fossil</string>
        </array>
        <key>WorkingDirectory</key>
        <string>/Users/you/museum</string>
        <key>KeepAlive</key>
        <true/>
        <key>RunAtLoad</key>
        <true/>
        <key>StandardErrorPath</key>
        <string>/tmp/fossil-error.log</string>
        <key>StandardOutPath</key>
        <string>/tmp/fossil-info.log</string>
        <key>UserName</key>
        <string>you</string>
        <key>GroupName</key>
        <string>staff</string>
        <key>InitGroups</key>
        <true/>
    </dict>
    </plist>
```

In this example, we’re assuming your development organization uses the
domain name “`dev.example.org`”, that your short macOS login name is
“`you`”, and that you store your Fossils in “`~/museum`”. Adjust these
elements of the plist file to suit your local situation.

You might be wondering about the use of `UserName`: isn’t Fossil
supposed to drop privileges and enter [a `chroot(2)`
jail](../../chroot.md) when it’s started as root like this? Why do we
need to give it a user name? Won’t Fossil use the owner of the
repository file to set that? All I can tell you is that in testing here,
if you leave the user and group configuration at the tail end of that
plist file out, Fossil will remain running as root!

Install that file and set it to start with:

        $ sudo install -o root -g wheel -m 644 com.example.dev.FossilHTTP.plist \
          /Library/LaunchDaemons/
        $ sudo launchctl load -w /Library/LaunchDaemons/com.example.dev.FossilHTTP.plist

Because we set the `RunAtLoad` key, this will also launch the daemon.

Stop the daemon with:

        $ sudo launchctl unload -w /Library/LaunchDaemons/com.example.dev.FossilHTTP.plist


## Socket Listener

Another useful method to serve a Fossil repo via `launchd` is by setting
up a socket listener:

```xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.example.dev.FossilSocket</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/fossil</string>
        <string>http</string>
        <string>repo.fossil</string>
    </array>
    <key>Sockets</key>
    <dict>
        <key>Listeners</key>
        <dict>
            <key>SockServiceName</key>
            <string>9001</string>
            <key>SockType</key>
            <string>stream</string>
            <key>SockProtocol</key>
            <string>TCP</string>
            <key>SockFamily</key>
            <string>IPv4</string>
        </dict>
    </dict>
    <key>inetdCompatibility</key>
    <dict>
        <key>Wait</key>
        <false/>
    </dict>
    <key>WorkingDirectory</key>
    <string>/Users/you/museum</string>
    <key>UserName</key>
    <string>you</string>
    <key>GroupName</key>
    <string>staff</string>
    <key>InitGroups</key>
    <true/>
</dict>
</plist>
```

Save it as “`com.example.dev.FossilSocket.plist`” and install and load
it into `launchd` as above.

This version differs in several key ways:

1.  We’re calling Fossil as `fossil http` rather than `fossil server` to
    make it serve a single request and then shut down immediately.

2.  We’ve told `launchd` to listen on our TCP port number instead of
    passing it to `fossil`.

3.  We’re running the daemon in `inetd` compatibility mode of `launchd`
    with “wait” mode off, which tells it to attach the connected socket
    to the `fossil` process’s stdio handles.

4.  We’ve removed the `Standard*Path` keys because they interfere with
    our use of stdio handles for HTTP I/O. You might therefore want to
    start with the first method and then switch over to this one only
    once you’ve got the daemon launching debugged, since once you tie up
    stdio this way, you won’t be able to get logging information from
    Fossil via that path. (Fossil does have some internal logging
    mechanisms, but you can’t get at them until Fossil is launching!)

5.  We’ve removed the `KeepAlive` and `RunAtLoad` keys because those
    options aren’t appropriate to this type of service.

6.  Because we’re running it via a socket listener instead of as a
    standalone HTTP server, the Fossil service only takes system
    resources when it’s actually handling an HTTP hit.  If your Fossil
    server is mostly idle, this method will be a bit more efficient than
    the first option.


*[Return to the top-level Fossil server article.](../)*

<title>Benefits Of A Fossil Server</title>

<h2>No Server Required</h2>

Fossil does <em>not</em> require a central server.
Data sharing and synchronization can be entirely peer-to-peer.
Fossil uses 
[https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type|conflict-free replicated data types]
to ensure that (in the limit) all participating peers see the same content.

<h2>But, A Server Can Be Useful</h2>

Fossil does not require a server, but a server can be very useful.
Here are a few reasons to set up a Fossil server for your project:

  1.  <b>A server gives developers a common point of rendezvous for
      syncing their work.</b><p>
      It is possible for developers to synchronous peer-to-peer but
      that requires the developers coordinate the sync, which in turn
      requires that the developers both want to sync at the same moment.
      A server aleviates this time dependency by allowing each developer
      to sync whenever it is convenient (for example, automatically syncing
      after each commit and before each update).  Developers all stay
      in sync with each other, without having to interrupt each other
      constantly to set up a peer-to-peer sync.

  2.  <b>A server works as a project website for non-developers.</b><p>
      Fossil does more than just version control.  It also supports
      trouble-tickets, and wiki, and a forum.  It shows the status
      of the project.  And the embedded documentation feature provides
      a great mechanism for providing only instructions.

  3.  <b>A server provides project leaders with up-to-date status.</b><p>
      Project coordinators and BDFLs can click on a link or two at the
      central Fossil server for a project, and quickly tell what is
      going on.  They can do this from anywhere, even from their phones,
      without needing to actually sync to the device they are using.

  4.  <b>A server provides automatic off-site backups.</b><p>
      A Fossil server is an automatic remote backup for all the work
      going into a project.  You can even set up multiple servers, at
      multiple sites, with automatic synchronization between them, for
      added redundancy.  Such a set up means that no work is lost due
      to a single machine failure.

# Serving via IIS + CGI

## This Is Not the Method You Are Looking For

Setting up CGI service under IIS is surprisingly complicated compared to
running Fossil as a CGI under most other operating systems. We recommend
that you use the simpler [reverse proxying method](./iis.md) instead
unless there is some compelling reason why that method cannot work for
you, such as its dependence on non-stock IIS extensions. (Keep in mind
that both extensions it requires are by Microsoft, not third parties!)

Once you’ve got this scheme working, it gives the same benefits as those
listed at the top of the linked-to document.

There is a small benefit you get from using CGI over reverse proxying on
other OSes, which is that the Fossil program only runs briefly in order
to serve each HTTP hit.  Once the request is done, that Fossil instance
shuts back down, releasing all of its resources. You don’t need to keep
a background Fossil HTTP server running full-time to provide CGI-based
Fossil service.

You lose a lot of that benefit on Windows:

1.  It only matters to start with on servers that are highly RAM
    constrained.  (Roughly ≤ 128 MiB.)  Our configuration steps below
    assume you’re using the Windows and IIS GUIs, which have RAM
    requirements well in excess of this, making Fossil’s resource
    requirements a drop in the bucket next to them. On the [Azure
    B1s][b1s] virtual machine I used to prepare these instructions, the
    Windows Server Manager GUI kept filling the VM’s 1 GiB of RAM
    during feature installation and crashing. I had to upgrade the VM’s
    RAM to 2 GiB just to get useful work done!

2.  Process creation on Windows is [much more expensive][cp] than on the
    other OSes Fossil runs on, so the benefits of firing up a Fossil
    executable to process each HTTP request are partially swamped by the
    overhead of doing so.

Therefore, unless you’re willing to replace all of the GUI configuration
steps below with command line equivalents, or shut the GUI down entirely
after configuring IIS, CGI is a much less compelling option on Windows.

**WARNING:** The following tutorial appears to fail with the current
(2019-08-17) version of Fossil, [apparently][fbug] due to an inability
of Fossil to detect that it’s being run in CGI mode.

[b1s]:  https://azure.microsoft.com/en-us/blog/introducing-b-series-our-new-burstable-vm-size/
[cp]:   https://stackoverflow.com/a/48244/142454
[fbug]: https://fossil-scm.org/forum/forumpost/de18dc32c0


## Install IIS with CGI Support

The steps for this are identical to those for the [reverse proxying IIS
setup](./iis.md#install) except that you need to enable CGI in the last
step, since it isn’t installed by default. For Windows Server, the path
is:

![Install CGI in IIS](./cgi-install-iis.png)

The path is similar on the consumer-focused versions of Windows, once
you get to that last step.


## Setup

1.  Install the Fossil executable to `c:\inetpub\wwwroot\bin` on the web
    server. We can’t use an executable you might already have because IIS
    runs under a separate user account, so we need to give that
    executable special permissions, and that’s easiest to do under the
    IIS tree:

    ![IIS fossil.exe execute permission](./cgi-bin-perm.png)

2.  In IIS Manager (a.k.a. `INETMGR`) drill down into the Sites folder
    in the left-side pane and right-click your web site’s
    configuration. (e.g. “Default Web Site”)

3.  On that menu say “Add Virtual Directory.” Give it the alias “`cgi`”
    and point it at a suitable directory, such as
    “`c:\inetpub\wwwroot\cgi`”.

4.  Double-click the “Handler Mappings” icon, then in the right-side
    pane, click “Add Script Map...” Apply the following settings:

    ![IIS script map dialog](./cgi-script-map.png)

    The Executable path must point to the path we set up in step 1, not
    to some other `fossil.exe` you may have elsewhere on your system.
    You will need to change the default “`*.dll`” filter in the Open
    dialog to “`*.exe`” in order to see it when browsing via the “`...`”
    button.

5.  Create a file called `repo.fslcgi` within the CGI directory you
    chose in step 3, with a single line like this:

        repository: c:\Users\SOMEONE\museum\repo.fossil

    Give the actual path to the repository, of course.

6.  Up at the top level of IIS Manager, double-click the “ISAPI and CGI
    Restrictions” icon, then click “Add...” in the right-side pane.
    Give the script you just created permission to execute:

    ![IIS CGI execute permission](./cgi-exec-perm.png)

7.  In the right-side pane, click “Restart” to apply this configuration,
    then test it by visiting the newly-available URL in a browser:

        http://localhost/cgi/repo.fslcgi

For more complicated setups such as “directory” mode, see [the generic
CGI instructions](../any/cgi.md).

*[Return to the top-level Fossil server article.](../)*

# Serving via IIS

## Why Bother?

The first part of the scheme below sets Fossil up as an HTTP server, so
you might be wondering why you wouldn’t just modify that to make it
listen on all network interfaces on TCP port 80, so you can avoid the
need for IIS entirely. For simple use cases, you can indeed do without
IIS, but there are several use cases where adding it is helpful:

1.  Proxying Fossil with IIS lets you [add TLS encryption][tls], which
    [Fossil does not currently speak](../../ssl.wiki) in its server role.

2.  The URL rewriting we do below allows Fossil to be part of a larger
    site already being served with IIS.

3.  You can have a mixed-mode site, with Fossil acting as a powerful
    dynamic content management service and IIS as a fast static content
    server.  The pure-Fossil alternative requires that you check all of
    your static content into Fossil as versioned or unversioned
    artifacts.

This article shows how you can get any combination of those benefits by
using IIS as a reverse proxy for `fossil server`.

There are other ways to use IIS to serve Fossil, such as [via
CGI](./cgi.md).


## Background Fossil Service Setup

You will need to have the Fossil HTTP server running in the background,
serving some local repository, bound to localhost on a fixed
high-numbered TCP port. For the purposes of testing, simply start it by
hand in your command shell of choice:

        fossil serve --port 9000 --localhost repo.fossil

That command assumes you’ve got `fossil.exe` in your `%PATH%` and you’re
in a directory holding `repo.fossil`. See [the platform-independent
instructions](../any/none.md) for further details.

For a more robust setup, we recommend that you [install Fossil as a
Windows service](./service.md), which will allow Fossil to start at
system boot, before anyone has logged in interactively.


## <a name="install"></a>Install IIS

IIS might not be installed in your system yet, so follow the path
appropriate to your host OS.  We’ve tested only the latest Microsoft
OSes as of the time of this writing, but the basic process should be
similar on older OSes.


### Windows Server 2019

1.  Start “Server Manager”
2.  Tell it you want to “Add roles and features”
3.  Select “Role-based or feature-based installation”
4.  Select your local server
5.  In the Server Roles section, enable “Web Server (IIS)”

### Windows 

1.  Open Control Panel
2.  Go to “Programs”
3.  Select “Turn Windows features on or off” in the left-side pane
4.  In the “Windows Features” dialog, enable “Internet Information
    Services”

The default set of IIS features there will suffice for this tutorial,
but you might want to enable additional features.


## Setting up the Proxy

The stock IIS setup doesn’t have reverse proxying features, but they’re
easily added through extensions. You will need to install the
[Application Request Routing][arr] and [URL Rewrite][ure] extensions. In
my testing here, URL Rewrite showed up immediately after installing it,
but I had to reboot the server to get ARR to show up. (Yay Windows.)

You can install these things through the direct links above, or you can
do it via the Web Platform Installer feature of IIS Manager (a.k.a.
`INETMGR`).

Set these extensions up in IIS Manager like so:

1.  Double-click the “Application Request Routing Cache” icon.

2.  Right-click in the window that results, and select “Server Proxy
    Settings...”

3.  Check the “Enable Proxy” box in the dialog. Click the “Apply” text
    in the right-side pane.

4.  Return to the top server-level configuration area of IIS Manager and
    double-click the “URL Rewrite” icon. Alternately, you might find
    “URL Rewrite” in the right-side pane from within the ARR settings.

5.  Right click in the window that results, and click “Add Rule(s)...”
    Tell it you want a “Blank rule” under “Inbound rules”.

6.  In the dialog that results, create a new rule called “Fossil repo
    proxy.” Set the “Pattern” to “`^(.*)$`” and “Rewrite URL” set to
    “`http://localhost:9000/{R:1}`”. That tells it to take everything in
    the path part of the URL and send it down to localhost:9000, where
    `fossil server` is listening.

7.  Click “Apply” in the right-side pane, then get back to the top level
    configuration for the server, and click “Restart” in that same pane.

At this point, if you go to `http://localhost/` in your browser, you
should see your Fossil repository’s web interface instead of the default
IIS web site, as before you did all of the above.

This is a very simple configuration. You can do more complicated and
interesting things with this, such as redirecting only `/code` URLs to
Fossil by setting the Pattern in step 6 to “`^/code(.*)$`”. (You would
also need to pass `--baseurl http://example.com/code` in the `fossil
server` command to make this work properly.) IIS would then directly
serve all other URLs. You could also intermix ASP.NET applications in
the URL scheme in this way.

See the documentation on [URL Rewrite rules][urr] for more ideas.

*[Return to the top-level Fossil server article.](../)*


[arr]: https://www.iis.net/downloads/microsoft/application-request-routing
[tls]: https://docs.microsoft.com/en-us/iis/manage/configuring-security/understanding-iis-url-authorization
[ure]: https://www.iis.net/downloads/microsoft/url-rewrite
[urr]: https://docs.microsoft.com/en-us/iis/extensions/url-rewrite-module/creating-rewrite-rules-for-the-url-rewrite-module

# Using Windows as a Fossil Server

- [Fossil as a Service](service.md)
- [Using stunnel with Fossil on Windows](stunnel.md)

*[Return to the top-level Fossil server article.](../)*