feat(backup): admin-tunable retention + BACKUP_KEY as a Komodo secret

Retention (keep-last / keep-daily-days) is operational policy the on-site admin
should tune, not a server env var requiring a redeploy -- same reasoning that moved
the target directory to the UI.

- Migration 0017: site_config.backup_keep_last + backup_keep_daily_days (nullable;
  null = code default 7 / 30 per field).
- BackupService reads retention fresh each run; status() exposes keepLast +
  keepDailyDays. DEFAULT_BACKUP_RETENTION is now a pure code default (env reads gone).
- PUT /api/backup/config accepts keepLast / keepDailyDays (non-negative int, or null
  to reset to default; 400 on negative).
- UI: two retention fields on the Backup config card; one Save covers target +
  retention. i18n sq + en.

BACKUP_KEY wired into Komodo:
- komodo/resources.toml: BACKUP_KEY=[[park_buzi_backup_key]] (per-booth secret,
  alongside JWT / signing keys).
- komodo/.env.komodo.example: documents it as the ONLY backup env var -- escrow it
  offsite alongside EVENT_SIGNING_KEY (recovery needs both); target + retention are
  admin-chosen in the UI / DB, not env. Server .env.example trimmed to just BACKUP_KEY.

Also carries the small in-progress setup-intro i18n copy trim.

Tests: 218 server tests green, incl. retention persist / reset-to-default / reject-
negative and the updated status shape. Migration applies cleanly (needed a
statement-breakpoint between the two ALTERs). Wiki backup-recovery updated.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/server/.env.example

@@ -25,10 +25,9 @@ EVENT_SIGNING_KEY=
 # rotate without fracturing the signed chain. Generate with:  openssl rand -hex 32
 # Escrow it offsite (alongside EVENT_SIGNING_KEY) — recovery needs both, and neither is ever
 # stored inside the backup it unlocks. Backups stay a no-op until BOTH this key and an in-UI
-# target directory are set.
+# target directory are set. The target directory AND retention (keep-last / keep-daily) are
+# admin-chosen in the UI (Setup → Backup), NOT env — only this key is an env secret.
 #   BACKUP_KEY=
-#   BACKUP_KEEP_LAST=7                # keep this many newest backups always
-#   BACKUP_KEEP_DAILY_DAYS=30         # plus one-per-day within this window
 
 # Optional ----------------------------------------------------------------
 # PORT=3000

apps/server/src/backup-service.ts

@@ -3,7 +3,7 @@ import { access, stat } from "node:fs/promises";
 import { resolve } from "node:path";
 import { eq, siteConfig, type Db } from "@parking/db";
 import type { FastifyBaseLogger } from "fastify";
-import { DEFAULT_BACKUP_RETENTION, runBackup, type BackupResult } from "./backup.js";
+import { DEFAULT_BACKUP_RETENTION, runBackup, type BackupResult, type BackupRetention } from "./backup.js";
 
 // Thin coordinator around the backup engine (backup.ts). The TARGET DIRECTORY is admin-chosen
 // and stored in site_config.backup_target_dir (read fresh each run, so changing it in the UI
@@ -28,6 +28,9 @@ export interface BackupStatus {
   readonly configured: boolean;
   /** The admin-chosen target dir (null if unset) — surfaced so the UI can show/edit it. */
   readonly targetDir: string | null;
+  /** Admin-tuned retention (resolved: DB value or code default) — surfaced for the UI form. */
+  readonly keepLast: number;
+  readonly keepDailyDays: number;
   /** Whether the env key is present + long enough (the UI flags a missing key distinctly). */
   readonly keyPresent: boolean;
   readonly running: boolean;
@@ -79,6 +82,18 @@ export class BackupService {
     return dir ? dir : null;
   }
 
+  /** Resolved retention from site_config, falling back to the code default per field. Read fresh. */
+  retention(): BackupRetention {
+    const row = this.#db.select().from(siteConfig).where(eq(siteConfig.id, 1)).get();
+    const keepLast = row?.backupKeepLast;
+    const keepDailyDays = row?.backupKeepDailyDays;
+    return {
+      keepLast: keepLast != null && keepLast >= 0 ? keepLast : DEFAULT_BACKUP_RETENTION.keepLast,
+      keepDailyDays:
+        keepDailyDays != null && keepDailyDays >= 0 ? keepDailyDays : DEFAULT_BACKUP_RETENTION.keepDailyDays,
+    };
+  }
+
   get keyPresent(): boolean {
     return backupKeyFromEnv().length >= 16;
   }
@@ -88,9 +103,12 @@ export class BackupService {
   }
 
   status(): BackupStatus {
+    const r = this.retention();
     return {
       configured: this.configured,
       targetDir: this.targetDir(),
+      keepLast: r.keepLast,
+      keepDailyDays: r.keepDailyDays,
       keyPresent: this.keyPresent,
       running: this.#running,
       lastSuccessAt: this.#lastSuccessAt,
@@ -120,7 +138,7 @@ export class BackupService {
     this.#inflight = (async () => {
       try {
         this.#logger?.info(`backup: starting (${trigger}) → ${targetDir}`);
-        const res = await runBackup(this.#db, { targetDir, key, retention: DEFAULT_BACKUP_RETENTION }, this.#logger);
+        const res = await runBackup(this.#db, { targetDir, key, retention: this.retention() }, this.#logger);
         this.#lastResult = res;
         this.#lastSuccessAt = new Date().toISOString();
         this.#lastError = null;

apps/server/src/backup.ts

@@ -40,9 +40,11 @@ export interface BackupRetention {
   readonly keepDailyDays: number;
 }
 
+// Code defaults — the fallback when the admin hasn't set a value in site_config (the source of
+// truth). NOT env-driven: retention is operational policy tuned from the Backup screen.
 export const DEFAULT_BACKUP_RETENTION: BackupRetention = {
-  keepLast: Number(process.env.BACKUP_KEEP_LAST ?? 7),
-  keepDailyDays: Number(process.env.BACKUP_KEEP_DAILY_DAYS ?? 30),
+  keepLast: 7,
+  keepDailyDays: 30,
 };
 
 export interface BackupOptions {

apps/server/src/routes/backup.routes.test.ts

@@ -50,6 +50,8 @@ describe("GET /api/backup/status", () => {
     expect(body).toMatchObject({
       configured: false,
       targetDir: null,
+      keepLast: 7, // code defaults surfaced when unset
+      keepDailyDays: 30,
       running: false,
       lastSuccessAt: null,
       lastError: null,
@@ -99,6 +101,37 @@ describe("PUT /api/backup/config — admin-chosen target", () => {
     });
     expect(clear.json().targetDir).toBeNull();
   });
+
+  it("persists retention and resets to defaults on null", async () => {
+    const { username, password } = await seedUser(db, { username: "boss", roleId: "admin" });
+    const { cookie, csrf } = await login(app, username, password);
+
+    const set = await app.inject({
+      method: "PUT", url: "/api/backup/config",
+      headers: { cookie, "x-csrf-token": csrf },
+      payload: { keepLast: 3, keepDailyDays: 14 },
+    });
+    expect(set.json()).toMatchObject({ keepLast: 3, keepDailyDays: 14 });
+
+    // null resets to the code default.
+    const reset = await app.inject({
+      method: "PUT", url: "/api/backup/config",
+      headers: { cookie, "x-csrf-token": csrf },
+      payload: { keepLast: null, keepDailyDays: null },
+    });
+    expect(reset.json()).toMatchObject({ keepLast: 7, keepDailyDays: 30 });
+  });
+
+  it("rejects a negative retention value (400)", async () => {
+    const { username, password } = await seedUser(db, { username: "boss", roleId: "admin" });
+    const { cookie, csrf } = await login(app, username, password);
+    const res = await app.inject({
+      method: "PUT", url: "/api/backup/config",
+      headers: { cookie, "x-csrf-token": csrf },
+      payload: { keepLast: -1 },
+    });
+    expect(res.statusCode).toBe(400);
+  });
 });
 
 describe("POST /api/backup/test — path probe", () => {

apps/server/src/routes/backup.ts

@@ -13,6 +13,10 @@ import { checkTargetDir, type BackupService } from "../backup-service.js";
 
 interface ConfigBody {
   targetDir?: string | null;
+  /** Retention: keep this many newest backups. null = reset to the code default. */
+  keepLast?: number | null;
+  /** Retention: keep one-per-day within this many days. null = reset to the code default. */
+  keepDailyDays?: number | null;
 }
 interface TestBody {
   targetDir?: string;
@@ -28,18 +32,37 @@ export async function backupRoutes(app: FastifyInstance, db: Db, backups: Backup
     "/api/backup/config",
     { preHandler: requirePermission("backup:update") },
     async (req, reply) => {
-      const raw = req.body?.targetDir;
-      if (raw != null && typeof raw !== "string") {
-        return reply.code(400).send({ error: "targetDir must be a string or null" });
+      const body = req.body ?? {};
+      const patch: { backupTargetDir?: string | null; backupKeepLast?: number | null; backupKeepDailyDays?: number | null } = {};
+
+      if ("targetDir" in body) {
+        const raw = body.targetDir;
+        if (raw != null && typeof raw !== "string") {
+          return reply.code(400).send({ error: "targetDir must be a string or null" });
+        }
+        patch.backupTargetDir = raw == null ? null : raw.trim() || null;
       }
-      const next = raw == null ? null : raw.trim() || null;
+      // Retention: a non-negative integer, or null to reset to the code default.
+      for (const [field, col] of [
+        ["keepLast", "backupKeepLast"],
+        ["keepDailyDays", "backupKeepDailyDays"],
+      ] as const) {
+        if (field in body) {
+          const v = body[field];
+          if (v != null && (!Number.isInteger(v) || v < 0)) {
+            return reply.code(400).send({ error: `${field} must be a non-negative integer or null` });
+          }
+          patch[col] = v ?? null;
+        }
+      }
+
       const updatedAt = new Date().toISOString();
       // Single-row site_config (id=1): upsert, since a fresh install may not have it yet.
       const existing = db.select().from(siteConfig).where(eq(siteConfig.id, 1)).get();
       if (existing) {
-        db.update(siteConfig).set({ backupTargetDir: next, updatedAt }).where(eq(siteConfig.id, 1)).run();
+        db.update(siteConfig).set({ ...patch, updatedAt }).where(eq(siteConfig.id, 1)).run();
       } else {
-        db.insert(siteConfig).values({ id: 1, backupTargetDir: next, updatedAt }).run();
+        db.insert(siteConfig).values({ id: 1, ...patch, updatedAt }).run();
       }
       return backups.status();
     },

apps/web/src/BackupSettings.tsx

@@ -5,7 +5,7 @@ import {
   ApiError,
   fetchBackupStatus,
   runBackup,
-  setBackupTarget,
+  setBackupConfig,
   testBackupTarget,
   type BackupStatus,
   type TargetCheck,
@@ -56,6 +56,8 @@ export function BackupSettings() {
   const qc = useQueryClient();
   const [toast, setToast] = useState<{ kind: "ok" | "err"; msg: string } | null>(null);
   const [target, setTarget] = useState("");
+  const [keepLast, setKeepLast] = useState("");
+  const [keepDaily, setKeepDaily] = useState("");
   const [check, setCheck] = useState<{ kind: "ok" | "err"; msg: string } | null>(null);
 
   const q = useQuery({
@@ -65,13 +67,22 @@ export function BackupSettings() {
   });
   const status = q.data;
 
-  // Seed the editable field from the saved value once it loads (and when it changes server-side).
+  // Seed the editable fields from the saved values once they load (and on server-side change).
   useEffect(() => {
-    if (status) setTarget(status.targetDir ?? "");
-  }, [status?.targetDir]);
+    if (status) {
+      setTarget(status.targetDir ?? "");
+      setKeepLast(String(status.keepLast));
+      setKeepDaily(String(status.keepDailyDays));
+    }
+  }, [status?.targetDir, status?.keepLast, status?.keepDailyDays]);
 
   const save = useMutation({
-    mutationFn: () => setBackupTarget(target.trim() || null),
+    mutationFn: () =>
+      setBackupConfig({
+        targetDir: target.trim() || null,
+        keepLast: keepLast.trim() === "" ? null : Number(keepLast),
+        keepDailyDays: keepDaily.trim() === "" ? null : Number(keepDaily),
+      }),
     onSuccess: (next) => {
       setToast({ kind: "ok", msg: t("backup.saved") });
       setCheck(null);
@@ -101,7 +112,10 @@ export function BackupSettings() {
     },
   });
 
-  const dirty = (status?.targetDir ?? "") !== target.trim();
+  const dirty =
+    (status?.targetDir ?? "") !== target.trim() ||
+    String(status?.keepLast ?? "") !== keepLast.trim() ||
+    String(status?.keepDailyDays ?? "") !== keepDaily.trim();
 
   return (
     <div className="">
@@ -134,8 +148,9 @@ export function BackupSettings() {
         </div>
       )}
 
-      {/* Target directory — the admin-chosen destination. */}
+      {/* Config — admin-chosen destination + retention policy. */}
       <div className="card mb-3 p-4">
+        {/* Target directory + its Test probe. */}
         <div className="field">
           <span className="label">{t("backup.targetLabel")}</span>
           <div className="flex flex-wrap items-center gap-2">
@@ -156,17 +171,6 @@ export function BackupSettings() {
             >
               {t("backup.test")}
             </button>
-            <button
-              type="button"
-              className="btn btn-primary btn-sm"
-              disabled={save.isPending || !dirty}
-              onClick={() => {
-                setToast(null);
-                save.mutate();
-              }}
-            >
-              {t("backup.save")}
-            </button>
           </div>
           <span className="mt-1 text-[0.6875rem] text-term-muted">{t("backup.targetHint")}</span>
           {check && (
@@ -175,6 +179,46 @@ export function BackupSettings() {
             </span>
           )}
         </div>
+
+        {/* Retention — admin-tuned policy (how many backups to keep at the target). */}
+        <div className="mt-4 flex flex-wrap items-start gap-6">
+          <div className="field">
+            <span className="label">{t("backup.keepLastLabel")}</span>
+            <input
+              type="number"
+              min={0}
+              className="input w-28"
+              value={keepLast}
+              onChange={(e) => setKeepLast(e.target.value)}
+            />
+            <span className="mt-1 text-[0.6875rem] text-term-muted">{t("backup.keepLastHint")}</span>
+          </div>
+          <div className="field">
+            <span className="label">{t("backup.keepDailyLabel")}</span>
+            <input
+              type="number"
+              min={0}
+              className="input w-28"
+              value={keepDaily}
+              onChange={(e) => setKeepDaily(e.target.value)}
+            />
+            <span className="mt-1 text-[0.6875rem] text-term-muted">{t("backup.keepDailyHint")}</span>
+          </div>
+        </div>
+
+        <div className="mt-4 flex items-center gap-3">
+          <button
+            type="button"
+            className="btn btn-primary btn-sm"
+            disabled={save.isPending || !dirty}
+            onClick={() => {
+              setToast(null);
+              save.mutate();
+            }}
+          >
+            {t("backup.save")}
+          </button>
+        </div>
       </div>
 
       <div className="card p-4">

apps/web/src/api.ts

@@ -234,6 +234,9 @@ export interface BackupStatus {
   configured: boolean;
   /** Admin-chosen target directory (null = not set). */
   targetDir: string | null;
+  /** Admin-tuned retention (resolved value: DB or code default). */
+  keepLast: number;
+  keepDailyDays: number;
   /** Whether the env encryption key is present (a missing key is flagged distinctly). */
   keyPresent: boolean;
   running: boolean;
@@ -247,9 +250,16 @@ export async function fetchBackupStatus(): Promise<BackupStatus> {
   return apiFetch("/api/backup/status");
 }
 
-/** Set (or clear, with "") the admin-chosen target directory. Returns the new status. */
-export async function setBackupTarget(targetDir: string | null): Promise<BackupStatus> {
-  return apiFetch("/api/backup/config", { method: "PUT", body: JSON.stringify({ targetDir }) });
+export interface BackupConfigPatch {
+  /** "" clears the target. Omit a field to leave it unchanged; null resets retention to default. */
+  targetDir?: string | null;
+  keepLast?: number | null;
+  keepDailyDays?: number | null;
+}
+
+/** Update backup config (target dir and/or retention). Returns the new status. */
+export async function setBackupConfig(patch: BackupConfigPatch): Promise<BackupStatus> {
+  return apiFetch("/api/backup/config", { method: "PUT", body: JSON.stringify(patch) });
 }
 
 export interface TargetCheck {

apps/web/src/lib/i18n/en.ts

@@ -865,6 +865,10 @@ export const en: Catalog = {
     testNotDir: "The path is not a directory.",
     testNotWritable: "The directory is not writable.",
     keyMissing: "The encryption key (BACKUP_KEY) is missing on the server — set it to enable backups.",
+    keepLastLabel: "Keep last",
+    keepLastHint: "How many of the newest backups to always keep.",
+    keepDailyLabel: "Keep daily (days)",
+    keepDailyHint: "Beyond those, keep one backup per day for this many days.",
   },
   pay: {
     ticket: "Ticket",

apps/web/src/lib/i18n/sq.ts

@@ -881,6 +881,10 @@ export const sq = {
     testNotDir: "Rruga nuk është një dosje.",
     testNotWritable: "Dosja nuk është e shkruajtshme.",
     keyMissing: "Çelësi i enkriptimit (BACKUP_KEY) mungon në server — caktoje që kopja të aktivizohet.",
+    keepLastLabel: "Mbaj kopjet e fundit",
+    keepLastHint: "Numri i kopjeve më të reja që mbahen gjithmonë.",
+    keepDailyLabel: "Mbaj ditore (ditë)",
+    keepDailyHint: "Përtej atyre, mbaj një kopje për ditë për kaq ditë.",
   },
   pay: {
     ticket: "Bileta",