<chapter xmlns="http://docbook.org/ns/docbook"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    version="5.0"
    xml:id="module-taskserver">
 <title>Taskserver</title>
 <para>
  Taskserver is the server component of
  <link xlink:href="https://taskwarrior.org/">Taskwarrior</link>, a free and
  open source todo list application.
 </para>
 <para>
  <emphasis>Upstream documentation:</emphasis>
  <link xlink:href="https://taskwarrior.org/docs/#taskd"/>
 </para>
 <section xml:id="module-services-taskserver-configuration">
  <title>Configuration</title>

  <para>
   Taskserver does all of its authentication via TLS using client certificates,
   so you either need to roll your own CA or purchase a certificate from a
   known CA, which allows creation of client certificates. These certificates
   are usually advertised as <quote>server certificates</quote>.
  </para>

  <para>
   So in order to make it easier to handle your own CA, there is a helper tool
   called <command>nixos-taskserver</command> which manages the custom CA along
   with Taskserver organisations, users and groups.
  </para>

  <para>
   While the client certificates in Taskserver only authenticate whether a user
   is allowed to connect, every user has its own UUID which identifies it as an
   entity.
  </para>

  <para>
   With <command>nixos-taskserver</command> the client certificate is created
   along with the UUID of the user, so it handles all of the credentials needed
   in order to setup the Taskwarrior client to work with a Taskserver.
  </para>
 </section>
 <section xml:id="module-services-taskserver-nixos-taskserver-tool">
  <title>The nixos-taskserver tool</title>

  <para>
   Because Taskserver by default only provides scripts to setup users
   imperatively, the <command>nixos-taskserver</command> tool is used for
   addition and deletion of organisations along with users and groups defined
   by <xref linkend="opt-services.taskserver.organisations"/> and as well for
   imperative set up.
  </para>

  <para>
   The tool is designed to not interfere if the command is used to manually set
   up some organisations, users or groups.
  </para>

  <para>
   For example if you add a new organisation using <command>nixos-taskserver
   org add foo</command>, the organisation is not modified and deleted no
   matter what you define in
   <option>services.taskserver.organisations</option>, even if you're adding
   the same organisation in that option.
  </para>

  <para>
   The tool is modelled to imitate the official <command>taskd</command>
   command, documentation for each subcommand can be shown by using the
   <option>--help</option> switch.
  </para>
 </section>
 <section xml:id="module-services-taskserver-declarative-ca-management">
  <title>Declarative/automatic CA management</title>

  <para>
   Everything is done according to what you specify in the module options,
   however in order to set up a Taskwarrior client for synchronisation with a
   Taskserver instance, you have to transfer the keys and certificates to the
   client machine.
  </para>

  <para>
   This is done using <command>nixos-taskserver user export $orgname
   $username</command> which is printing a shell script fragment to stdout
   which can either be used verbatim or adjusted to import the user on the
   client machine.
  </para>

  <para>
   For example, let's say you have the following configuration:
<screen>
{
  <xref linkend="opt-services.taskserver.enable"/> = true;
  <xref linkend="opt-services.taskserver.fqdn"/> = "server";
  <xref linkend="opt-services.taskserver.listenHost"/> = "::";
  <link linkend="opt-services.taskserver.organisations._name_.users">services.taskserver.organisations.my-company.users</link> = [ "alice" ];
}
</screen>
   This creates an organisation called <literal>my-company</literal> with the
   user <literal>alice</literal>.
  </para>

  <para>
   Now in order to import the <literal>alice</literal> user to another machine
   <literal>alicebox</literal>, all we need to do is something like this:
<screen>
$ ssh server nixos-taskserver user export my-company alice | sh
</screen>
   Of course, if no SSH daemon is available on the server you can also copy
   &amp; paste it directly into a shell.
  </para>

  <para>
   After this step the user should be set up and you can start synchronising
   your tasks for the first time with <command>task sync init</command> on
   <literal>alicebox</literal>.
  </para>

  <para>
   Subsequent synchronisation requests merely require the command <command>task
   sync</command> after that stage.
  </para>
 </section>
 <section xml:id="module-services-taskserver-manual-ca-management">
  <title>Manual CA management</title>

  <para>
   If you set any options within
   <link linkend="opt-services.taskserver.pki.manual.ca.cert">service.taskserver.pki.manual</link>.*,
   <command>nixos-taskserver</command> won't issue certificates, but you can
   still use it for adding or removing user accounts.
  </para>
 </section>
</chapter>
