<chapter xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="module-services-nextcloud">
 <title>Nextcloud</title>
 <para>
  <link xlink:href="https://nextcloud.com/">Nextcloud</link> is an open-source,
  self-hostable cloud platform. The server setup can be automated using
  <link linkend="opt-services.nextcloud.enable">services.nextcloud</link>. A
  desktop client is packaged at <literal>pkgs.nextcloud-client</literal>.
 </para>
 <para>
  The current default by NixOS is <package>nextcloud22</package> which is also the latest
  major version available.
 </para>
 <section xml:id="module-services-nextcloud-basic-usage">
  <title>Basic usage</title>

  <para>
   Nextcloud is a PHP-based application which requires an HTTP server
   (<literal><link linkend="opt-services.nextcloud.enable">services.nextcloud</link></literal>
   optionally supports
   <literal><link linkend="opt-services.nginx.enable">services.nginx</link></literal>)
   and a database (it's recommended to use
   <literal><link linkend="opt-services.postgresql.enable">services.postgresql</link></literal>).
  </para>

  <para>
   A very basic configuration may look like this:
<programlisting>{ pkgs, ... }:
{
  services.nextcloud = {
    <link linkend="opt-services.nextcloud.enable">enable</link> = true;
    <link linkend="opt-services.nextcloud.hostName">hostName</link> = "nextcloud.tld";
    config = {
      <link linkend="opt-services.nextcloud.config.dbtype">dbtype</link> = "pgsql";
      <link linkend="opt-services.nextcloud.config.dbuser">dbuser</link> = "nextcloud";
      <link linkend="opt-services.nextcloud.config.dbhost">dbhost</link> = "/run/postgresql"; # nextcloud will add /.s.PGSQL.5432 by itself
      <link linkend="opt-services.nextcloud.config.dbname">dbname</link> = "nextcloud";
      <link linkend="opt-services.nextcloud.config.adminpassFile">adminpassFile</link> = "/path/to/admin-pass-file";
      <link linkend="opt-services.nextcloud.config.adminuser">adminuser</link> = "root";
    };
  };

  services.postgresql = {
    <link linkend="opt-services.postgresql.enable">enable</link> = true;
    <link linkend="opt-services.postgresql.ensureDatabases">ensureDatabases</link> = [ "nextcloud" ];
    <link linkend="opt-services.postgresql.ensureUsers">ensureUsers</link> = [
     { name = "nextcloud";
       ensurePermissions."DATABASE nextcloud" = "ALL PRIVILEGES";
     }
    ];
  };

  # ensure that postgres is running *before* running the setup
  systemd.services."nextcloud-setup" = {
    requires = ["postgresql.service"];
    after = ["postgresql.service"];
  };

  <link linkend="opt-networking.firewall.allowedTCPPorts">networking.firewall.allowedTCPPorts</link> = [ 80 443 ];
}</programlisting>
  </para>

  <para>
   The <literal>hostName</literal> option is used internally to configure an HTTP
   server using <literal><link xlink:href="https://php-fpm.org/">PHP-FPM</link></literal>
   and <literal>nginx</literal>. The <literal>config</literal> attribute set is
   used by the imperative installer and all values are written to an additional file
   to ensure that changes can be applied by changing the module's options.
  </para>

  <para>
   In case the application serves multiple domains (those are checked with
   <literal><link xlink:href="http://php.net/manual/en/reserved.variables.server.php">$_SERVER['HTTP_HOST']</link></literal>)
   it's needed to add them to
   <literal><link linkend="opt-services.nextcloud.config.extraTrustedDomains">services.nextcloud.config.extraTrustedDomains</link></literal>.
  </para>

  <para>
   Auto updates for Nextcloud apps can be enabled using
   <literal><link linkend="opt-services.nextcloud.autoUpdateApps.enable">services.nextcloud.autoUpdateApps</link></literal>.
</para>

 </section>

 <section xml:id="module-services-nextcloud-pitfalls-during-upgrade">
  <title>Common problems</title>
  <itemizedlist>
   <listitem>
    <formalpara>
     <title>General notes</title>
     <para>
      Unfortunately Nextcloud appears to be very stateful when it comes to
      managing its own configuration. The config file lives in the home directory
      of the <literal>nextcloud</literal> user (by default
      <literal>/var/lib/nextcloud/config/config.php</literal>) and is also used to
      track several states of the application (e.g., whether installed or not).
     </para>
    </formalpara>
    <para>
     All configuration parameters are also stored in
     <filename>/var/lib/nextcloud/config/override.config.php</filename> which is generated by
     the module and linked from the store to ensure that all values from
     <filename>config.php</filename> can be modified by the module.
     However <filename>config.php</filename> manages the application's state and shouldn't be
     touched manually because of that.
    </para>
    <warning>
     <para>Don't delete <filename>config.php</filename>! This file
     tracks the application's state and a deletion can cause unwanted
     side-effects!</para>
    </warning>

    <warning>
     <para>Don't rerun <literal>nextcloud-occ
     maintenance:install</literal>! This command tries to install the application
     and can cause unwanted side-effects!</para>
    </warning>
   </listitem>
   <listitem>
    <formalpara>
     <title>Multiple version upgrades</title>
     <para>
      Nextcloud doesn't allow to move more than one major-version forward. E.g., if you're on
      <literal>v16</literal>, you cannot upgrade to <literal>v18</literal>, you need to upgrade to
      <literal>v17</literal> first. This is ensured automatically as long as the
      <link linkend="opt-system.stateVersion">stateVersion</link> is declared properly. In that case
      the oldest version available (one major behind the one from the previous NixOS
      release) will be selected by default and the module will generate a warning that reminds
      the user to upgrade to latest Nextcloud <emphasis>after</emphasis> that deploy.
     </para>
    </formalpara>
   </listitem>
   <listitem>
    <formalpara>
     <title><literal>Error: Command "upgrade" is not defined.</literal></title>
     <para>
      This error usually occurs if the initial installation
      (<command>nextcloud-occ maintenance:install</command>) has failed. After that, the application
      is not installed, but the upgrade is attempted to be executed. Further context can
      be found in <link xlink:href="https://github.com/NixOS/nixpkgs/issues/111175">NixOS/nixpkgs#111175</link>.
     </para>
    </formalpara>
    <para>
     First of all, it makes sense to find out what went wrong by looking at the logs
     of the installation via <command>journalctl -u nextcloud-setup</command> and try to fix
     the underlying issue.
    </para>
    <itemizedlist>
     <listitem>
      <para>
       If this occurs on an <emphasis>existing</emphasis> setup, this is most likely because
       the maintenance mode is active. It can be deactivated by running
       <command>nextcloud-occ maintenance:mode --off</command>. It's advisable though to
       check the logs first on why the maintenance mode was activated.
      </para>
     </listitem>
     <listitem>
      <warning><para>Only perform the following measures on
      <emphasis>freshly installed instances!</emphasis></para></warning>
      <para>
       A re-run of the installer can be forced by <emphasis>deleting</emphasis>
       <filename>/var/lib/nextcloud/config/config.php</filename>. This is the only time
       advisable because the fresh install doesn't have any state that can be lost.
       In case that doesn't help, an entire re-creation can be forced via
       <command>rm -rf ~nextcloud/</command>.
      </para>
     </listitem>
    </itemizedlist>
   </listitem>
  </itemizedlist>
 </section>

 <section xml:id="module-services-nextcloud-httpd">
  <title>Using an alternative webserver as reverse-proxy (e.g. <literal>httpd</literal>)</title>
  <para>
   By default, <package>nginx</package> is used as reverse-proxy for <package>nextcloud</package>.
   However, it's possible to use e.g. <package>httpd</package> by explicitly disabling
   <package>nginx</package> using <xref linkend="opt-services.nginx.enable" /> and fixing the
   settings <literal>listen.owner</literal> &amp; <literal>listen.group</literal> in the
   <link linkend="opt-services.phpfpm.pools">corresponding <literal>phpfpm</literal> pool</link>.
  </para>
  <para>
   An exemplary configuration may look like this:
<programlisting>{ config, lib, pkgs, ... }: {
  <link linkend="opt-services.nginx.enable">services.nginx.enable</link> = false;
  services.nextcloud = {
    <link linkend="opt-services.nextcloud.enable">enable</link> = true;
    <link linkend="opt-services.nextcloud.hostName">hostName</link> = "localhost";

    /* further, required options */
  };
  <link linkend="opt-services.phpfpm.pools._name_.settings">services.phpfpm.pools.nextcloud.settings</link> = {
    "listen.owner" = config.services.httpd.user;
    "listen.group" = config.services.httpd.group;
  };
  services.httpd = {
    <link linkend="opt-services.httpd.enable">enable</link> = true;
    <link linkend="opt-services.httpd.adminAddr">adminAddr</link> = "webmaster@localhost";
    <link linkend="opt-services.httpd.extraModules">extraModules</link> = [ "proxy_fcgi" ];
    virtualHosts."localhost" = {
      <link linkend="opt-services.httpd.virtualHosts._name_.documentRoot">documentRoot</link> = config.services.nextcloud.package;
      <link linkend="opt-services.httpd.virtualHosts._name_.extraConfig">extraConfig</link> = ''
        &lt;Directory "${config.services.nextcloud.package}"&gt;
          &lt;FilesMatch "\.php$"&gt;
            &lt;If "-f %{REQUEST_FILENAME}"&gt;
              SetHandler "proxy:unix:${config.services.phpfpm.pools.nextcloud.socket}|fcgi://localhost/"
            &lt;/If&gt;
          &lt;/FilesMatch&gt;
          &lt;IfModule mod_rewrite.c&gt;
            RewriteEngine On
            RewriteBase /
            RewriteRule ^index\.php$ - [L]
            RewriteCond %{REQUEST_FILENAME} !-f
            RewriteCond %{REQUEST_FILENAME} !-d
            RewriteRule . /index.php [L]
          &lt;/IfModule&gt;
          DirectoryIndex index.php
          Require all granted
          Options +FollowSymLinks
        &lt;/Directory&gt;
      '';
    };
  };
}</programlisting>
  </para>
 </section>

 <section xml:id="installing-apps-php-extensions-nextcloud">
  <title>Installing Apps and PHP extensions</title>

  <para>
   Nextcloud apps are installed statefully through the web interface.

   Some apps may require extra PHP extensions to be installed.
   This can be configured with the <xref linkend="opt-services.nextcloud.phpExtraExtensions" /> setting.
  </para>

  <para>
   Alternatively, extra apps can also be declared with the <xref linkend="opt-services.nextcloud.extraApps" /> setting.
   When using this setting, apps can no longer be managed statefully because this can lead to Nextcloud updating apps
   that are managed by Nix. If you want automatic updates it is recommended that you use web interface to install apps.
  </para>
 </section>

 <section xml:id="module-services-nextcloud-maintainer-info">
  <title>Maintainer information</title>

  <para>
   As stated in the previous paragraph, we must provide a clean upgrade-path for Nextcloud
   since it cannot move more than one major version forward on a single upgrade. This chapter
   adds some notes how Nextcloud updates should be rolled out in the future.
  </para>

  <para>
   While minor and patch-level updates are no problem and can be done directly in the
   package-expression (and should be backported to supported stable branches after that),
   major-releases should be added in a new attribute (e.g. Nextcloud <literal>v19.0.0</literal>
   should be available in <literal>nixpkgs</literal> as <literal>pkgs.nextcloud19</literal>).
   To provide simple upgrade paths it's generally useful to backport those as well to stable
   branches. As long as the package-default isn't altered, this won't break existing setups.
   After that, the versioning-warning in the <literal>nextcloud</literal>-module should be
   updated to make sure that the
   <link linkend="opt-services.nextcloud.package">package</link>-option selects the latest version
   on fresh setups.
  </para>

  <para>
   If major-releases will be abandoned by upstream, we should check first if those are needed
   in NixOS for a safe upgrade-path before removing those. In that case we shold keep those
   packages, but mark them as insecure in an expression like this (in
   <literal>&lt;nixpkgs/pkgs/servers/nextcloud/default.nix&gt;</literal>):
<programlisting>/* ... */
{
  nextcloud17 = generic {
    version = "17.0.x";
    sha256 = "0000000000000000000000000000000000000000000000000000";
    eol = true;
  };
}</programlisting>
  </para>

  <para>
   Ideally we should make sure that it's possible to jump two NixOS versions forward:
   i.e. the warnings and the logic in the module should guard a user to upgrade from a
   Nextcloud on e.g. 19.09 to a Nextcloud on 20.09.
  </para>
 </section>
</chapter>
