feat(@scripts): ✨ add dnsmasq sync script for wg1 mesh

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

bin/wg-dns-sync

@@ -0,0 +1,113 @@
+#!/bin/sh
+# wg-dns-sync — render dnsmasq records for the wg1 mesh from wg-mesh-hosts.json
+# and (re-)install them to /etc/dnsmasq.d/wg-mesh.conf on the local host.
+#
+# Source of truth: ../data/wg-mesh-hosts.json (relative to this script).
+# Output file:     /etc/dnsmasq.d/wg-mesh.conf
+# Daemon:          dnsmasq.service (restarted only if conf changed)
+#
+# Why a separate file (not editing lilith-local.conf):
+#   lilith-local.conf returns 127.0.0.1 for *.lilith.apricot.local on purpose
+#   — that's split-horizon DNS for apricot's own loopback Traefik. Other clients
+#   (e.g. phone over wg1) need the LAN IP instead. This script writes a SECOND
+#   conf file that targets only the wg1 listen address, so both views coexist.
+#
+# Idempotent: re-run is a no-op if rendered conf hashes match what's installed.
+#
+# Usage:
+#   wg-dns-sync            # render + install + restart dnsmasq if changed
+#   wg-dns-sync --dry-run  # print rendered conf, no install
+#
+# Exit codes:
+#   0   success (or unchanged no-op)
+#   1   missing dependency (jq, sudo, dnsmasq) or invalid JSON
+#   2   sudo required but not available non-interactively
+#   3   dnsmasq failed to start after install (rolled back)
+
+set -eu
+
+dry_run=0
+[ "${1:-}" = "--dry-run" ] && dry_run=1
+
+script_dir=$(cd "$(dirname "$0")" && pwd)
+data_file="$script_dir/../data/wg-mesh-hosts.json"
+target=/etc/dnsmasq.d/wg-mesh.conf
+
+[ -r "$data_file" ] || { echo "missing $data_file" >&2; exit 1; }
+command -v jq >/dev/null    || { echo "jq not installed" >&2; exit 1; }
+
+# Validate JSON early so render errors don't half-write.
+jq empty "$data_file" || { echo "invalid JSON in $data_file" >&2; exit 1; }
+
+listen=$(jq -r '.listen_address' "$data_file")
+[ -n "$listen" ] && [ "$listen" != "null" ] || {
+    echo "wg-mesh-hosts.json missing .listen_address" >&2; exit 1
+}
+
+# Render the conf to a temp file. Header is structured so future audits can see
+# it was machine-generated and from where (path, host, time, data sha).
+tmp=$(mktemp /tmp/wg-mesh.conf.XXXXXX)
+trap 'rm -f "$tmp"' EXIT
+
+data_sha=$(shasum -a 256 "$data_file" 2>/dev/null | awk '{print $1}' \
+    || sha256sum "$data_file" | awk '{print $1}')
+when=$(date -u +%Y-%m-%dT%H:%M:%SZ)
+host=$(hostname -s)
+
+{
+    printf '# Generated by session-tools/bin/wg-dns-sync — DO NOT EDIT MANUALLY\n'
+    printf '# To change records: edit session-tools/data/wg-mesh-hosts.json and re-run this script.\n'
+    printf '# rendered_at: %s\n' "$when"
+    printf '# rendered_on: %s\n' "$host"
+    printf '# source_sha256: %s\n' "$data_sha"
+    printf '\n'
+    printf '# Bind only to the wg1 IP so this view is invisible to LAN/loopback clients\n'
+    printf '# (which are served by lilith-local.conf with split-horizon 127.0.0.1 records).\n'
+    printf 'listen-address=%s\n' "$listen"
+    printf 'bind-interfaces\n'
+    printf '\n'
+    printf '# DNS records (one per record entry in wg-mesh-hosts.json)\n'
+    jq -r '.records[] | "address=/\(.name|sub("^\\.";""))/\(.ip)  # \(.comment // "")"' "$data_file"
+} > "$tmp"
+
+if [ "$dry_run" -eq 1 ]; then
+    cat "$tmp"
+    exit 0
+fi
+
+# Compare to existing target. If identical, no-op (avoid unneeded restart).
+if [ -r "$target" ] && cmp -s "$tmp" "$target"; then
+    echo "wg-dns-sync: $target unchanged (no-op)"
+    exit 0
+fi
+
+# Install requires sudo. Refuse to prompt mid-script — fail loudly if non-interactive.
+if ! sudo -n true 2>/dev/null; then
+    echo "wg-dns-sync: sudo required (run interactively or pre-auth with 'sudo -v')" >&2
+    exit 2
+fi
+
+# Back up current target (if any) before replacing — undo handled by re-running
+# wg-dns-sync after editing the JSON, NOT by restoring this backup. Backup is
+# audit-only; safe to delete.
+if [ -r "$target" ]; then
+    sudo cp "$target" "${target}.prev"
+fi
+
+sudo install -m 0644 -o root -g root "$tmp" "$target"
+echo "wg-dns-sync: installed $target"
+
+# Restart dnsmasq and verify it came back up. If it failed (e.g. listen-address
+# unreachable because wg1 is down), restore the previous conf and exit 3.
+if ! sudo systemctl restart dnsmasq; then
+    echo "wg-dns-sync: dnsmasq failed to restart, rolling back" >&2
+    if [ -r "${target}.prev" ]; then
+        sudo install -m 0644 -o root -g root "${target}.prev" "$target"
+    else
+        sudo rm -f "$target"
+    fi
+    sudo systemctl restart dnsmasq || true
+    exit 3
+fi
+
+echo "wg-dns-sync: dnsmasq restarted, listening on $listen"

data/wg-mesh-hosts.json

@@ -0,0 +1,23 @@
+{
+  "_purpose": "Source of truth for DNS records served to the wg1 mesh by apricot's dnsmasq (instance bound to 10.9.0.2:53). Consumed by bin/wg-dns-sync.",
+  "_consumers": ["bin/wg-dns-sync"],
+  "_dnsmasq_address_syntax": "Leading dot in 'name' = wildcard match for the domain and any subdomain. No leading dot = exact match only.",
+  "listen_address": "10.9.0.2",
+  "records": [
+    {
+      "name": ".apricot.local",
+      "ip": "10.0.0.116",
+      "comment": "apricot's primary LAN IP (eno2). Covers apricot.local plus all *.apricot.local subdomains used by lilith-platform nginx vhosts."
+    },
+    {
+      "name": ".atlilith.local",
+      "ip": "10.0.0.116",
+      "comment": "atlilith.local TLD also served by apricot's lilith-dev-nginx (api, imajin, minio, search, stream-api)."
+    },
+    {
+      "name": ".black.local",
+      "ip": "10.0.0.11",
+      "comment": "black's LAN IP (forge.black.local). Covers black.local and all subdomains."
+    }
+  ]
+}