Add --headless mode (no stdin read, runs until SIGTERM/exit) + systemd/NixOS examples

2026-10-18 15:24:20 +00:00
parent c204e1ef0c
commit 01a821ab72
7 changed files with 144 additions and 9 deletions
@@ -0,0 +1,33 @@
+# 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;
+      };
+    };
+  };
+}
@@ -0,0 +1,23 @@
+# 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