{ config, pkgs, ... }:
{
  imports = [
    ./syncthing.nix
  ];

  # Update and start Jinja-Compose project
  # during boot and after every 30 minutes.
  # To view the log, run
  #   journalctl -b -u Jinja-Compose -f
  #
  systemd.timers."Jinja-Compose" = {
    wantedBy = [ "timers.target" ];
    partOf = [ "Jinja-Compose.service" ];
    timerConfig = {
      OnBootSec = "0m";
      OnUnitInactiveSec = "30m";

      AccuracySec = "1m";
      RandomizedDelaySec = "1m";
    };
  };
  # TODO: Add shutdown script (./docker-compose down).
  systemd.services."Jinja-Compose" = {
    description = "Update and start Jinja-Compose project";
    serviceConfig = {
      Type = "oneshot";
      PrivateTmp = true;
      User = "root";
    };
    path = with pkgs; [
      # The `docker-compose` helper script is written in `bash` (!)
      bash
      docker
    ];
    script = ''
      set -eu -o pipefail

      # We use one of the following
      #   some-command 2> >(sed 's/^/<3> /' >&2)
      #   some-command 2>&1 | sed 's/^/<3> /' 1>&2
      # to prefix each line of stdout and stderr from some-command with
      #   "<3> "
      # Source: https://superuser.com/a/882025/919675
      #
      # With this prefix, the stderr output is treated as error messages by systemd.
      # See https://www.freedesktop.org/software/systemd/man/latest/sd-daemon.html
      # They can be viewed with
      #   journalctl -b -u Jinja-Compose.service

      /jc-config/docker-compose pull         2>&1 | sed 's/^/<3> /'
      /jc-config/docker-compose up -d --wait 2>&1 | sed 's/^/<3> /'
    '';
  };
}