<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-litestream">
 <title>Litestream</title>
 <para>
  <link xlink:href="https://litestream.io/">Litestream</link> is a standalone streaming
  replication tool for SQLite.
 </para>

 <section xml:id="module-services-litestream-configuration">
  <title>Configuration</title>

  <para>
   Litestream service is managed by a dedicated user named <literal>litestream</literal>
   which needs permission to the database file. Here's an example config which gives
   required permissions to access <link linkend="opt-services.grafana.database.path">
   grafana database</link>:
<programlisting>
{ pkgs, ... }:
{
  users.users.litestream.extraGroups = [ "grafana" ];

  systemd.services.grafana.serviceConfig.ExecStartPost = "+" + pkgs.writeShellScript "grant-grafana-permissions" ''
    timeout=10

    while [ ! -f /var/lib/grafana/data/grafana.db ];
    do
      if [ "$timeout" == 0 ]; then
        echo "ERROR: Timeout while waiting for /var/lib/grafana/data/grafana.db."
        exit 1
      fi

      sleep 1

      ((timeout--))
    done

    find /var/lib/grafana -type d -exec chmod -v 775 {} \;
    find /var/lib/grafana -type f -exec chmod -v 660 {} \;
  '';

  services.litestream = {
    enable = true;

    environmentFile = "/run/secrets/litestream";

    settings = {
      dbs = [
        {
          path = "/var/lib/grafana/data/grafana.db";
          replicas = [{
            url = "s3://mybkt.litestream.io/grafana";
          }];
        }
      ];
    };
  };
}
</programlisting>
  </para>
 </section>

</chapter>
