headless: register signal handlers synchronously, split tests, drop deployment examples and wording

examples/systemd/sausage.nix

@@ -1,33 +0,0 @@
-# NixOS module: runs a Sausage world as a service (see README, "As a service").
-# Create the world once: sudo -u sausage nix run git+https://gitea.surma.technology/surma/sausage -- init /var/lib/sausage/world
-{ config, lib, pkgs, ... }:
-let cfg = config.services.sausage; in
-{
-  options.services.sausage = {
-    enable = lib.mkEnableOption "the Sausage world";
-    world = lib.mkOption { type = lib.types.str; default = "/var/lib/sausage/world"; };
-    flake = lib.mkOption {
-      type = lib.types.str;
-      default = "git+https://gitea.surma.technology/surma/sausage";
-    };
-  };
-  config = lib.mkIf cfg.enable {
-    users.users.sausage = { isSystemUser = true; group = "sausage"; home = "/var/lib/sausage"; createHome = true; };
-    users.groups.sausage = { };
-    systemd.services.sausage = {
-      description = "Sausage world";
-      wantedBy = [ "multi-user.target" ];
-      after = [ "network-online.target" ];
-      wants = [ "network-online.target" ];
-      path = [ pkgs.nix pkgs.git ];
-      serviceConfig = {
-        User = "sausage";
-        WorkingDirectory = "/var/lib/sausage";
-        ExecStart = "${pkgs.nix}/bin/nix run ${cfg.flake}#loop -- --headless ${cfg.world}";
-        Restart = "on-failure";
-        RestartSec = 5;
-        TimeoutStopSec = 30;
-      };
-    };
-  };
-}

examples/systemd/sausage.service

@@ -1,23 +0,0 @@
-# Sausage as a systemd service. Create the world once as the service user:
-#   nix run git+https://gitea.surma.technology/surma/sausage -- init /var/lib/sausage/world
-# Then: install as /etc/systemd/system/sausage.service, `systemctl enable --now sausage`.
-# Adjust User and the path to `nix`.
-[Unit]
-Description=Sausage world
-After=network-online.target
-Wants=network-online.target
-
-[Service]
-User=sausage
-WorkingDirectory=/var/lib/sausage
-# The loop restarts the host (newest version) after a crash or a broker `exit`.
-# --headless: no console, stdin EOF does not stop the world.
-ExecStart=/run/current-system/sw/bin/nix run git+https://gitea.surma.technology/surma/sausage#loop -- --headless /var/lib/sausage/world
-Restart=on-failure
-RestartSec=5
-# SIGTERM stops the host cleanly (exit code 0).
-KillMode=control-group
-TimeoutStopSec=30
-
-[Install]
-WantedBy=multi-user.target