scripts/proxmox/configure-nix-cache-client.sh

@@ -6,27 +6,31 @@
 #
 # This is the non-NixOS equivalent of modules/nix-cache/client.nix +
 # modules/nix-cache/remote-builder-client.nix -- those two only apply to
-# hosts built from this flake. A plain Debian box with Nix installed
+# hosts built from this flake. A plain Debian box with Nix installed has no
-# (single- or multi-user install, nix-daemon running) has no NixOS module
+# NixOS module system to pick that config up, so this edits nix.conf by hand.
-# system to pick that config up, so this edits /etc/nix/nix.conf by hand
+#
-# instead. Run this ON the target Debian machine, as root.
+# Two modes depending on who runs it:
+#
+#   root (multi-user / daemon install):
+#     Writes /etc/nix/nix.conf, /etc/ssh/ssh_known_hosts, restarts nix-daemon.
+#     Requires /etc/nix/nix.conf to already exist (i.e. nix-daemon is set up).
+#     Run as: sudo ./configure-nix-cache-client.sh [options]
+#
+#   non-root (single-user install):
+#     Writes ~/.config/nix/nix.conf, ~/.ssh/known_hosts. No daemon to restart.
+#     Run as: ./configure-nix-cache-client.sh [options]
 #
 # The values below mirror variables.nix / modules/nix-cache/client.nix in
 # this repo -- update both if nix-cache is ever rebuilt with a new host
 # key or the cache signing key is rotated (see docs/nix-cache.md).
 #
-# REMOTE_BUILDER_KEY defaults to this machine's own default root SSH
+# REMOTE_BUILDER_KEY defaults to the running user's default SSH identity
-# identity (matches modules/nix-cache/remote-builder-client.nix's
+# (root: /root/.ssh/id_ed25519, other user: ~/.ssh/id_ed25519). That key
-# convention for real NixOS clients: authenticate as nixremote with the
+# must be listed in vars.remoteBuilderAuthorizedKeys in this repo and
-# host's own default key, added individually to
+# nix-cache rebuilt before remote building works.
-# vars.remoteBuilderAuthorizedKeys, rather than a separately-named or
-# shared keypair) -- generate one with
-# `ssh-keygen -t ed25519 -N '' -f /root/.ssh/id_ed25519` if this machine
-# doesn't have one yet, then add its .pub to vars.remoteBuilderAuthorizedKeys
-# and rebuild nix-cache.
 #
 # Usage:
-#   sudo ./configure-nix-cache-client.sh [--dry-run] [--no-remote-builder] [--no-restart]
+#   ./configure-nix-cache-client.sh [--dry-run] [--no-remote-builder] [--no-restart]
 #
 # Env overrides (defaults match variables.nix):
 #   NIX_CACHE_HOST, NIX_CACHE_HOST_KEY, REMOTE_BUILDER_USER, REMOTE_BUILDER_KEY
@@ -36,17 +40,28 @@ set -euo pipefail
 : "${NIX_CACHE_HOST:=nix-cache}"
 : "${NIX_CACHE_HOST_KEY:=ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPeWgMsdaiz4axT/deFc1+0B5bN+GX/NOeW9bbQ0c/IT lxc-nix-cache}"
 : "${REMOTE_BUILDER_USER:=nixremote}"
-: "${REMOTE_BUILDER_KEY:=/root/.ssh/id_ed25519}"
 
 CACHE_PUB_KEY="cache.local-1:usoWYanY3Kpq2+kDIS2nhWoLZiRxanmdysdzqCFBHW4="
 FALLBACK_URL="https://cache.nixos.org/"
 FALLBACK_PUB_KEY="cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
 
-NIX_CONF="/etc/nix/nix.conf"
-KNOWN_HOSTS="/etc/ssh/ssh_known_hosts"
 MARKER_BEGIN="# BEGIN nix-cache client config (configure-nix-cache-client.sh)"
 MARKER_END="# END nix-cache client config"
 
+# Mode: root uses system-wide paths and restarts the daemon; non-root uses
+# user-level paths and has no daemon to restart.
+if [[ "$EUID" -eq 0 ]]; then
+  install_mode="multi"
+  NIX_CONF="/etc/nix/nix.conf"
+  KNOWN_HOSTS="/etc/ssh/ssh_known_hosts"
+  : "${REMOTE_BUILDER_KEY:=/root/.ssh/id_ed25519}"
+else
+  install_mode="single"
+  NIX_CONF="${XDG_CONFIG_HOME:-$HOME/.config}/nix/nix.conf"
+  KNOWN_HOSTS="$HOME/.ssh/known_hosts"
+  : "${REMOTE_BUILDER_KEY:=$HOME/.ssh/id_ed25519}"
+fi
+
 dry_run=0
 with_remote_builder=1
 restart_daemon=1
@@ -57,7 +72,7 @@ for arg in "$@"; do
     --no-remote-builder) with_remote_builder=0 ;;
     --no-restart) restart_daemon=0 ;;
     -h|--help)
-      sed -n '2,20p' "$0"
+      sed -n '2,37p' "$0"
       exit 0
       ;;
     *)
@@ -67,21 +82,22 @@ for arg in "$@"; do
   esac
 done
 
-if [[ "$dry_run" -eq 0 && "$EUID" -ne 0 ]]; then
-  echo "ERROR: must run as root (writes $NIX_CONF and, unless --no-remote-builder, $KNOWN_HOSTS)." >&2
-  exit 1
-fi
-
 if ! command -v nix >/dev/null 2>&1; then
   echo "ERROR: no 'nix' binary on PATH -- install the Nix package manager first." >&2
   exit 1
 fi
 
-if [[ ! -f "$NIX_CONF" ]]; then
+if [[ "$install_mode" == "multi" && ! -f "$NIX_CONF" ]]; then
   echo "ERROR: $NIX_CONF not found -- expected an existing multi-user Nix install." >&2
   exit 1
 fi
 
+# Single-user: create the config file if it doesn't exist yet.
+if [[ "$install_mode" == "single" && "$dry_run" -eq 0 ]]; then
+  mkdir -p "$(dirname "$NIX_CONF")"
+  [[ -f "$NIX_CONF" ]] || touch "$NIX_CONF"
+fi
+
 builder_line=""
 if [[ "$with_remote_builder" -eq 1 ]]; then
   if [[ -f "$REMOTE_BUILDER_KEY" ]]; then
@@ -117,7 +133,7 @@ fi
 block="${block}
 $MARKER_END"
 
-echo "== nix.conf block to install =="
+echo "== nix.conf block to install ($NIX_CONF) =="
 echo "$block"
 echo "================================"
 
@@ -159,7 +175,8 @@ if [[ "$with_remote_builder" -eq 1 ]]; then
   fi
 fi
 
-if [[ "$dry_run" -eq 0 && "$restart_daemon" -eq 1 ]]; then
+# Only restart the daemon for multi-user installs -- single-user has no daemon.
+if [[ "$dry_run" -eq 0 && "$restart_daemon" -eq 1 && "$install_mode" == "multi" ]]; then
   if command -v systemctl >/dev/null 2>&1 && systemctl is-active --quiet nix-daemon 2>/dev/null; then
     systemctl restart nix-daemon
     echo "Restarted nix-daemon to pick up the new config."