(*:maxLineLen=78:*)
theory Phabricator
imports Base
begin
chapter \<open>Phabricator server setup \label{ch:phabricator}\<close>
text \<open>
Phabricator\<^footnote>\<open>\<^url>\<open>https://www.phacility.com/phabricator\<close>\<close> is an open-source
product to support the development process of complex software projects
(open or closed ones). The official slogan is:
\begin{quote}
Discuss. Plan. Code. Review. Test. \\
Every application your project needs, all in one tool.
\end{quote}
Ongoing changes and discussions about changes are maintained uniformly
within a MySQL database. There are standard connections to major version
control systems: \<^bold>\<open>Subversion\<close>, \<^bold>\<open>Mercurial\<close>, \<^bold>\<open>Git\<close>. So Phabricator offers
a counter-model to trends of monoculture and centralized version control,
especially due to Microsoft's Github and Atlassian's Bitbucket.
The small company behind Phabricator provides paid plans for support and
hosting of servers, but it is easy to do \<^emph>\<open>independent self-hosting\<close> on a
standard LAMP server (Linux, Apache, MySQL, PHP). This merely requires a
virtual machine on the Net, which can be rented cheaply from local hosting
providers --- there is no need to follow big cloud corporations. So it is
feasible to remain the master of your virtual home, following the slogan
``own all your data''. In many respects, Phabricator is similar to the
well-known Nextcloud\<^footnote>\<open>\<^url>\<open>https://nextcloud.com\<close>\<close> product, concerning both
the technology and sociology.
\<^medskip>
The following Phabricator instances may serve as examples:
\<^item> Wikimedia development \<^url>\<open>https://phabricator.wikimedia.org\<close>
\<^item> Mozilla development \<^url>\<open>https://phabricator.services.mozilla.com\<close>
\<^item> Isabelle development \<^url>\<open>https://isabelle-dev.sketis.net\<close>
\<^item> Phabricator development (mostly inactive after Jun-2021) \<^url>\<open>https://secure.phabricator.com\<close>
\<^item> Phorge development (community fork and successor of Phabricator)
\<^url>\<open>https://we.phorge.it\<close>
\<^medskip>
Initial Phabricator configuration requires many details to be done right.
Isabelle provides some command-line tools to help with the setup, and
afterwards Isabelle support is optional: it is possible to run and maintain
the server, without requiring the somewhat bulky Isabelle distribution
again.
\<^medskip>
Assuming an existing Phabricator installation, the command-line tool @{tool
hg_setup} (\secref{sec:hg-setup}) helps to create new repositories or to
migrate old ones. In particular, this avoids the lengthy sequence of clicks
in Phabricator to make a new private repository with hosting on the server.
(Phabricator is a software project management platform, where initial
repository setup happens rarely in practice.)
\<close>
section \<open>Quick start\<close>
text \<open>
The starting point is a fresh installation of \<^bold>\<open>Ubuntu 20.04
LTS\<close>\<^footnote>\<open>\<^url>\<open>https://ubuntu.com/download\<close>\<close>: this version is mandatory due to
subtle dependencies on system packages and configuration that is assumed by
the Isabelle setup tool.
For production use, a proper \<^emph>\<open>Virtual Server\<close> or \<^emph>\<open>Root Server\<close> product
from a hosting provider will be required, including an Internet Domain Name
(\secref{sec:phabricator-domain}).
Initial experimentation also works on a local host, e.g.\ via
VirtualBox\<^footnote>\<open>\<^url>\<open>https://www.virtualbox.org\<close>\<close>. The proforma domain
\<^verbatim>\<open>localhost\<close> is used by default: it maps arbitrary subdomains to the usual
\<^verbatim>\<open>localhost\<close> address. This allows to use e.g.
\<^verbatim>\<open>http://phabricator-vcs.localhost\<close> for initial setup as described below.
All administrative commands need to be run as \<^verbatim>\<open>root\<close> user (e.g.\ via
\<^verbatim>\<open>sudo\<close>). Note that Isabelle refers to user-specific configuration in the
user home directory via @{setting ISABELLE_HOME_USER}
(\secref{sec:settings}); that may be different or absent for the root user
and thus cause confusion.
\<close>
subsection \<open>Initial setup\<close>
text \<open>
Isabelle can manage multiple named Phabricator installations: this allows to
separate administrative responsibilities, e.g.\ different approaches to user
management for different projects. Subsequently we always use the default
name ``\<^verbatim>\<open>vcs\<close>'': the name will appear in file and directory locations,
internal database names and URLs.
The initial setup works as follows (with full Linux package upgrade):
@{verbatim [display] \<open> isabelle phabricator_setup -U -M:\<close>}
After installing many packages, cloning the Phabricator distribution,
initializing the MySQL database and Apache, the tool prints an URL for
further configuration. Now the following needs to be provided by the web
interface.
\<^item> An initial user that will get administrator rights. There is no need to
create a special \<^verbatim>\<open>admin\<close> account. Instead, a regular user that will take
over this responsibility can be used here. Subsequently we assume that
user \<^verbatim>\<open>makarius\<close> becomes the initial administrator.
\<^item> An \<^emph>\<open>Auth Provider\<close> to manage user names and passwords. None is provided
by default, and Phabricator points out this omission prominently in its
overview of \<^emph>\<open>Setup Issues\<close>: following these hints quickly leads to the
place where a regular \<^emph>\<open>Username/Password\<close> provider can be added.
Alternatively, Phabricator can delegate the responsibility of
authentication to big corporations like Google and Facebook, but these can
be easily ignored. Genuine self-hosting means to manage users directly,
without outsourcing of authentication.
\<^item> A proper password for the administrator can now be set, e.g.\ by the
following command:
@{verbatim [display] \<open> isabelle phabricator bin/auth recover makarius\<close>}
The printed URL gives access to a login and password dialog in the web
interface.
Any further users will be able to provide a password directly, because the
Auth Provider is already active.
\<^item> The list of Phabricator \<^bold>\<open>Setup Issues\<close> should be studied with some
care, to make sure that no serious problems are remaining. For example,
the request to lock the configuration can be fulfilled as follows:
@{verbatim [display] \<open> isabelle phabricator bin/auth lock\<close>}
\<^medskip> A few other Setup Issues might be relevant as well, e.g.\ the timezone
of the server. Some more exotic points can be ignored: Phabricator
provides careful explanations about what it thinks could be wrong, while
leaving some room for interpretation.
\<close>
subsection \<open>Mailer configuration\<close>
text \<open>
The next important thing is messaging: Phabricator needs to be able to
communicate with users on its own account, e.g.\ to reset passwords. The
documentation has many variations on \<^emph>\<open>Configuring Outbound
Email\<close>\<^footnote>\<open>\<^url>\<open>https://secure.phabricator.com/book/phabricator/article/configuring_outbound_email\<close>\<close>,
but a conventional SMTP server with a dedicated \<^verbatim>\<open>phabricator\<close> user is
sufficient. There is no need to run a separate mail server on the
self-hosted Linux machine: hosting providers often include such a service
for free, e.g.\ as part of a web-hosting package. As a last resort it is
also possible to use a corporate service like Gmail, but such dependency
dilutes the whole effort of self-hosting.
\<^medskip>
Mailer configuration requires a few command-line invocations as follows:
@{verbatim [display] \<open> isabelle phabricator_setup_mail\<close>}
\<^noindent> This generates a JSON template file for the mail account details.
After editing that, the subsequent command will add and test it with
Phabricator:
@{verbatim [display] \<open> isabelle phabricator_setup_mail -T makarius\<close>}
This tells Phabricator to send a message to the administrator created
before; the output informs about success or errors.
The mail configuration process can be refined and repeated until it works
properly: host name, port number, protocol etc.\ all need to be correct. The
\<^verbatim>\<open>key\<close> field in the JSON file identifies the name of the configuration that
will be overwritten each time, when taking over the parameters via
\<^verbatim>\<open>isabelle phabricator_setup_mail\<close>.
\<^medskip>
The effective mail configuration can be queried like this:
@{verbatim [display] \<open> isabelle phabricator bin/config get cluster.mailers\<close>}
\<close>
subsection \<open>SSH configuration\<close>
text \<open>
SSH configuration is important to access hosted repositories with public-key
authentication. It is done by a separate tool, because it affects the
operating-system and all installations of Phabricator simultaneously.
The subsequent configuration is convenient (and ambitious): it takes away
the standard port 22 from the operating system and assigns it to
Isabelle/Phabricator.
@{verbatim [display] \<open> isabelle phabricator_setup_ssh -p 22 -q 222\<close>}
Afterwards, remote login to the server host needs to use that alternative
port 222. If there is a problem connecting again, the administrator can
usually access a remote console via some web interface of the virtual server
provider.
\<^medskip>
The following alternative is more modest: it uses port 2222 for Phabricator,
and retains port 22 for the operating system.
@{verbatim [display] \<open> isabelle phabricator_setup_ssh -p 2222 -q 22\<close>}
\<^medskip>
The tool can be invoked multiple times with different parameters; ports are
changed back and forth each time and services restarted.
\<close>
subsection \<open>Internet domain name and HTTPS configuration \label{sec:phabricator-domain}\<close>
text \<open>
So far the Phabricator server has been accessible only on \<^verbatim>\<open>localhost\<close>.
Proper configuration of a public Internet domain name (with HTTPS
certificate from \<^emph>\<open>Let's Encrypt\<close>) works as follows.
\<^item> Register a subdomain (e.g.\ \<^verbatim>\<open>vcs.example.org\<close>) as an alias for the IP
address of the underlying Linux host. This usually works by some web
interface of the hosting provider to edit DNS entries; it might require
some time for updated DNS records to become publicly available.
\<^item> Edit the Phabricator website configuration file in
\<^path>\<open>/etc/apache2/sites-available/\<close> to specify \<^verbatim>\<open>ServerName\<close> and
\<^verbatim>\<open>ServerAdmin\<close> like this: @{verbatim [display] \<open> ServerName vcs.example.org
ServerAdmin webmaster@example.org\<close>}
Then reload (or restart) Apache like this:
@{verbatim [display] \<open> systemctl reload apache2\<close>}
\<^item> Install \<^verbatim>\<open>certbot\<close> from \<^url>\<open>https://certbot.eff.org\<close> following the
description for Apache and Ubuntu 20 on
\<^url>\<open>https://certbot.eff.org/instructions?ws=apache&os=ubuntufocal\<close>. Run
\<^verbatim>\<open>certbot\<close> interactively and let it operate on the domain
\<^verbatim>\<open>vcs.example.org\<close>.
\<^item> Inform Phabricator about its new domain name like this:
@{verbatim [display] \<open> isabelle phabricator bin/config set \
phabricator.base-uri https://vcs.example.org\<close>}
\<^item> Visit the website \<^verbatim>\<open>https://vcs.example.org\<close> and configure Phabricator
as described before. The following options are particularly relevant for a
public website:
\<^item> \<^emph>\<open>Auth Provider / Username/Password\<close>: disable \<^emph>\<open>Allow Registration\<close> to
avoid uncontrolled registrants; users can still be invited via email
instead.
\<^item> Enable \<^verbatim>\<open>policy.allow-public\<close> to allow read-only access to resources,
without requiring user registration.
\<^item> Adjust \<^verbatim>\<open>phabricator.cookie-prefix\<close> for multiple installations with
overlapping domains (see also the documentation of this configuration
option within Phabricator).
\<close>
section \<open>Global data storage and backups \label{sec:phabricator-backup}\<close>
text \<open>
The global state of a Phabricator installation consists of two main parts:
\<^enum> The \<^emph>\<open>root directory\<close> according to
\<^path>\<open>/etc/isabelle-phabricator.conf\<close> or \<^verbatim>\<open>isabelle phabricator -l\<close>: it
contains the main PHP program suite with administrative tools, and some
configuration files. The default setup also puts hosted repositories here
(subdirectory \<^verbatim>\<open>repo\<close>).
\<^enum> Multiple \<^emph>\<open>MySQL databases\<close> with a common prefix derived from the
installation name --- the same name is used as database user name.
The root user may invoke \<^verbatim>\<open>/usr/local/bin/isabelle-phabricator-dump\<close> to
create a complete database dump within the root directory. Afterwards it is
sufficient to make a conventional \<^bold>\<open>file-system backup\<close> of everything. To
restore the database state, see the explanations on \<^verbatim>\<open>mysqldump\<close> in
\<^url>\<open>https://secure.phabricator.com/book/phabricator/article/configuring_backups\<close>;
some background information is in
\<^url>\<open>https://secure.phabricator.com/book/phabflavor/article/so_many_databases\<close>.
\<^medskip> The following command-line tools are particularly interesting for advanced
database maintenance (within the Phabricator root directory):
@{verbatim [display] \<open> phabricator/bin/storage help dump
phabricator/bin/storage help shell
phabricator/bin/storage help destroy
phabricator/bin/storage help renamespace\<close>}
For example, copying a database snapshot from one installation to another
works as follows. Run on the first installation root directory:
@{verbatim [display] \<open> phabricator/bin/storage dump > dump1.sql
phabricator/bin/storage renamespace --from phabricator_vcs \
--to phabricator_xyz --input dump1.sql --output dump2.sql\<close>}
Then run on the second installation root directory:
@{verbatim [display] \<open> phabricator/bin/storage destroy
phabricator/bin/storage shell < .../dump2.sql\<close>}
Local configuration in \<^verbatim>\<open>phabricator/config/local/\<close> and hosted repositories
need to be treated separately within the file-system. For the latter
see also these tools:
@{verbatim [display] \<open> phabricator/bin/repository help list-paths
phabricator/bin/repository help move-paths\<close>}
\<close>
section \<open>Upgrading Phabricator installations\<close>
text \<open>
The Phabricator developers publish a new version approx.\ every 1--4 weeks:
see also \<^url>\<open>https://secure.phabricator.com/w/changelog\<close>. There is no need to
follow such frequent updates on the spot, but it is a good idea to upgrade
occasionally --- with the usual care to avoid breaking a production system
(see also \secref{sec:phabricator-backup} for database dump and backup).
The Isabelle/Phabricator setup provides a convenience tool to upgrade all
installations uniformly:
@{verbatim [display] \<open> /usr/local/bin/isabelle-phabricator-upgrade\<close>}
This refers to the \<^verbatim>\<open>stable\<close> branch of the distribution repositories by
default. Alternatively, it also possible to use the \<^verbatim>\<open>master\<close> like this:
@{verbatim [display] \<open> /usr/local/bin/isabelle-phabricator-upgrade master\<close>}
\<^medskip>
See
\<^url>\<open>https://secure.phabricator.com/book/phabricator/article/upgrading\<close> for
further explanations on Phabricator upgrade.
\<close>
section \<open>Reference of command-line tools\<close>
text \<open>
The subsequent command-line tools usually require root user privileges on
the underlying Linux system (e.g.\ via \<^verbatim>\<open>sudo bash\<close> to open a subshell, or
directly via \<^verbatim>\<open>sudo isabelle phabricator ...\<close>).
\<close>
subsection \<open>\<^verbatim>\<open>isabelle phabricator\<close>\<close>
text \<open>
The @{tool_def phabricator} tool invokes a GNU bash command-line within the
Phabricator home directory:
@{verbatim [display]
\<open>Usage: isabelle phabricator [OPTIONS] COMMAND [ARGS...]
Options are:
-l list available Phabricator installations
-n NAME Phabricator installation name (default: "vcs")
Invoke a command-line tool within the home directory of the named
Phabricator installation.\<close>}
Isabelle/Phabricator installations are registered in the global
configuration file \<^path>\<open>/etc/isabelle-phabricator.conf\<close>, with name and
root directory separated by colon (no extra whitespace). The home directory
is the subdirectory \<^verbatim>\<open>phabricator\<close> within the root.
\<^medskip> Option \<^verbatim>\<open>-l\<close> lists the available Phabricator installations with name and
root directory --- without invoking a command.
Option \<^verbatim>\<open>-n\<close> selects the explicitly named Phabricator installation.
\<close>
subsubsection \<open>Examples\<close>
text \<open>
Print the home directory of the Phabricator installation:
@{verbatim [display] \<open> isabelle phabricator pwd\<close>}
Print some Phabricator configuration information:
@{verbatim [display] \<open> isabelle phabricator bin/config get phabricator.base-uri\<close>}
The latter conforms to typical command templates seen in the original
Phabricator documentation:
@{verbatim [display] \<open> phabricator/ $ ./bin/config get phabricator.base-uri\<close>}
Here the user is meant to navigate to the Phabricator home manually, in
contrast to \<^verbatim>\<open>isabelle phabricator\<close> doing it automatically thanks to the
global configuration \<^path>\<open>/etc/isabelle-phabricator.conf\<close>.
\<close>
subsection \<open>\<^verbatim>\<open>isabelle phabricator_setup\<close>\<close>
text \<open>
The @{tool_def phabricator_setup} tool installs a fresh Phabricator instance
on Ubuntu 20.04 or 22.04 LTS:
@{verbatim [display] \<open>Usage: isabelle phabricator_setup [OPTIONS]
Options are:
-M SOURCE install Mercurial from source: local PATH, or URL, or ":"
-R DIR repository directory (default: "/var/www/phabricator-NAME/repo")
-U full update of system packages before installation
-n NAME Phabricator installation name (default: "vcs")
-o OPTION override Isabelle system OPTION (via NAME=VAL or NAME)
-r DIR installation root directory (default: "/var/www/phabricator-NAME")
Install Phabricator as LAMP application (Linux, Apache, MySQL, PHP).
The installation name (default: "vcs") is mapped to a regular
Unix user; this is relevant for public SSH access.\<close>}
Installation requires Linux root permissions. All required packages are
installed automatically beforehand, this includes the Apache web server and
the MySQL database engine.
Global configuration in \<^verbatim>\<open>/etc\<close> or a few other directories like \<^verbatim>\<open>/var/www\<close>
uses name prefixes like \<^verbatim>\<open>isabelle-phabricator\<close> or \<^verbatim>\<open>phabricator\<close>. Local
configuration for a particular installation uses more specific names derived
from \<^verbatim>\<open>phabricator-\<close>\<open>NAME\<close>, e.g.\ \<^verbatim>\<open>/var/www/phabricator-vcs\<close> for the
default.
Knowing the naming conventions, it is possible to purge a Linux installation
from Isabelle/Phabricator with some effort, but there is no automated
procedure for de-installation. In the worst case, it might be better to
re-install the virtual machine from a clean image.
\<^medskip>
Option \<^verbatim>\<open>-U\<close> ensures a full update of system packages, before installing
further packages required by Phabricator. This might require a reboot.
Option \<^verbatim>\<open>-M:\<close> installs a standard Mercurial release from source --- the one
that is used by the Phabricator hosting service
\<^url>\<open>https://admin.phacility.com\<close>. This avoids various problems with the
package provided by Ubuntu 20.04. Alternatively, an explicit file path or
URL the source archive (\<^verbatim>\<open>.tar.gz\<close>) may be given here. This option is
recommended for production use, but it requires to \<^emph>\<open>uninstall\<close> existing
Mercurial packages provided by the operating system.
Option \<^verbatim>\<open>-n\<close> provides an alternative installation name. The default name
\<^verbatim>\<open>vcs\<close> means ``version control system''. The name appears in the URL for SSH
access, and thus has some relevance to end-users. The initial server URL
also uses the same suffix, but that can (and should) be changed later via
regular Apache configuration.
Option \<^verbatim>\<open>-o\<close> augments the environment of Isabelle system options: relevant
options for Isabelle/Phabricator have the prefix ``\<^verbatim>\<open>phabricator_\<close>'' (see
also the result of e.g. ``\<^verbatim>\<open>isabelle options -l\<close>'').
Option \<^verbatim>\<open>-r\<close> specifies an alternative installation root directory: it needs
to be accessible for the Apache web server.
Option \<^verbatim>\<open>-R\<close> specifies an alternative directory for repositories that are
hosted by Phabricator. Provided that it is accessible for the Apache web
server, the directory can be reused for the \<^verbatim>\<open>hgweb\<close> view by Mercurial.\<^footnote>\<open>See
also the documentation
\<^url>\<open>https://www.mercurial-scm.org/wiki/PublishingRepositories\<close> and the
example \<^url>\<open>https://isabelle.sketis.net/repos\<close>.\<close>
\<close>
subsection \<open>\<^verbatim>\<open>isabelle phabricator_setup_mail\<close>\<close>
text \<open>
The @{tool_def phabricator_setup_mail} tool provides mail configuration for
an existing Phabricator installation:
@{verbatim [display] \<open>Usage: isabelle phabricator_setup_mail [OPTIONS]
Options are:
-T USER send test mail to Phabricator user
-f FILE config file (default: "mailers.json" within
Phabricator root)
-n NAME Phabricator installation name (default: "vcs")
Provide mail configuration for existing Phabricator installation.\<close>}
Proper mail configuration is vital for Phabricator, but the details can be
tricky. A common approach is to re-use an existing SMTP mail service, as is
often included in regular web hosting packages. It is sufficient to create
one mail account for multiple Phabricator installations, but the
configuration needs to be set for each installation.
The first invocation of \<^verbatim>\<open>isabelle phabricator_setup_mail\<close> without options
creates a JSON template file. Its \<^verbatim>\<open>key\<close> entry should be changed to
something sensible to identify the configuration, e.g.\ the Internet Domain
Name of the mail address. The \<^verbatim>\<open>options\<close> specify the SMTP server address and
account information.
Another invocation of \<^verbatim>\<open>isabelle phabricator_setup_mail\<close> with updated JSON
file will change the underlying Phabricator installation. This can be done
repeatedly, until everything works as expected.
Option \<^verbatim>\<open>-T\<close> invokes a standard Phabricator test procedure for the mail
configuration. The argument needs to be a valid Phabricator user: the mail
address is derived from the user profile.
Option \<^verbatim>\<open>-f\<close> refers to an existing JSON configuration file, e.g.\ from a
previous successful Phabricator installation: sharing mailers setup with the
same mail address is fine for outgoing mails; incoming mails are optional
and not configured here.
\<close>
subsection \<open>\<^verbatim>\<open>isabelle phabricator_setup_ssh\<close>\<close>
text \<open>
The @{tool_def phabricator_setup_ssh} tool configures a special SSH service
for all Phabricator installations:
@{verbatim [display] \<open>Usage: isabelle phabricator_setup_ssh [OPTIONS]
Options are:
-p PORT sshd port for Phabricator servers (default: 2222)
-q PORT sshd port for the operating system (default: 22)
Configure ssh service for all Phabricator installations: a separate sshd
is run in addition to the one of the operating system, and ports need to
be distinct.
A particular Phabricator installation is addressed by using its
name as the ssh user; the actual Phabricator user is determined via
stored ssh keys.\<close>}
This is optional, but very useful. It allows to refer to hosted repositories
via ssh with the usual public-key authentication. It also allows to
communicate with a Phabricator server via the JSON API of
\<^emph>\<open>Conduit\<close>\<^footnote>\<open>\<^url>\<open>https://secure.phabricator.com/book/phabricator/article/conduit\<close>\<close>.
\<^medskip> The Phabricator SSH server distinguishes installations by their name,
e.g.\ \<^verbatim>\<open>vcs\<close> as SSH user name. The public key that is used for
authentication identifies the user within Phabricator: there is a web
interface to provide that as part of the user profile.
The operating system already has an SSH server (by default on port 22) that
remains important for remote administration of the machine.
\<^medskip>
Options \<^verbatim>\<open>-p\<close> and \<^verbatim>\<open>-q\<close> allow to change the port assignment for both
servers. A common scheme is \<^verbatim>\<open>-p 22 -q 222\<close> to leave the standard port to
Phabricator, to simplify the ssh URL that users will see for remote
repository clones.\<^footnote>\<open>For the rare case of hosting Subversion repositories,
port 22 is de-facto required. Otherwise Phabricator presents malformed
\<^verbatim>\<open>svn+ssh\<close> URLs with port specification.\<close>
Redirecting the operating system sshd to port 222 requires some care: it
requires to adjust the remote login procedure, e.g.\ in \<^verbatim>\<open>$HOME/.ssh/config\<close>
to add a \<^verbatim>\<open>Port\<close> specification for the server machine.
\<close>
end