feat: track unique logins

lib/telemetry/index.ts

@@ -3,6 +3,7 @@ export { buildPayload, markProcessStart } from './payload';
 export {
   loadState, saveState, getInstanceId, effectiveConsent,
 } from './state';
+export { recordLogin, getLoginCounts } from './login-tracker';
 export type {
   TelemetryPayload, TelemetryStateFile, ConsentState,
   Platform, OsFamily, CountBucket, TelemetryFeatures,

lib/telemetry/login-tracker.ts

@@ -0,0 +1,125 @@
+import { readFile, writeFile, mkdir, rename } from 'node:fs/promises';
+import { existsSync } from 'node:fs';
+import path from 'node:path';
+import { createHmac } from 'node:crypto';
+import { logger } from '@/lib/logger';
+import { getInstanceId } from './state';
+
+// We never store usernames or server URLs in the clear. Each login is
+// recorded as HMAC-SHA256(username + '@' + serverUrl, instance_id), so the
+// file on disk cannot be cross-correlated with any other instance and is
+// not PII even if leaked.
+
+interface LoginRecord {
+  id: string;
+  lastLoginAt: string;
+}
+
+interface LoginsFile {
+  records: LoginRecord[];
+}
+
+const SEVEN_DAYS_MS = 7 * 24 * 60 * 60 * 1000;
+const RETENTION_MS = 90 * 24 * 60 * 60 * 1000;
+
+let cache: LoginsFile | null = null;
+
+function getDir(): string {
+  return process.env.TELEMETRY_DATA_DIR || path.join(process.cwd(), 'data', 'telemetry');
+}
+
+function loginsPath(): string {
+  return path.join(getDir(), 'logins.json');
+}
+
+async function ensureDir(): Promise<void> {
+  const dir = getDir();
+  if (!existsSync(dir)) await mkdir(dir, { recursive: true });
+}
+
+async function loadFile(): Promise<LoginsFile> {
+  if (cache) return cache;
+  try {
+    const raw = await readFile(loginsPath(), 'utf8');
+    const parsed = JSON.parse(raw) as Partial<LoginsFile>;
+    cache = Array.isArray(parsed?.records) ? { records: parsed.records as LoginRecord[] } : { records: [] };
+  } catch {
+    cache = { records: [] };
+  }
+  return cache;
+}
+
+async function saveFile(file: LoginsFile): Promise<void> {
+  await ensureDir();
+  cache = file;
+  const tmp = loginsPath() + '.tmp';
+  await writeFile(tmp, JSON.stringify(file), 'utf8');
+  await rename(tmp, loginsPath());
+}
+
+function normalizeServer(serverUrl: string): string {
+  return serverUrl.trim().replace(/\/+$/, '').toLowerCase();
+}
+
+async function hashIdentity(username: string, serverUrl: string): Promise<string> {
+  const instanceId = await getInstanceId();
+  const subject = `${username.trim().toLowerCase()}@${normalizeServer(serverUrl)}`;
+  return createHmac('sha256', instanceId).update(subject).digest('hex').slice(0, 32);
+}
+
+/**
+ * Record a successful login. Best-effort; never throws. Updates the
+ * existing record's timestamp if the same identity has logged in before,
+ * otherwise appends a new record. Records older than the retention window
+ * are pruned on every write.
+ */
+export async function recordLogin(username: string, serverUrl: string): Promise<void> {
+  if (!username || !serverUrl) return;
+  try {
+    const id = await hashIdentity(username, serverUrl);
+    const file = await loadFile();
+    const now = new Date().toISOString();
+    const cutoff = Date.now() - RETENTION_MS;
+    const next: LoginRecord[] = [];
+    let updated = false;
+    for (const rec of file.records) {
+      const ts = new Date(rec.lastLoginAt).getTime();
+      if (Number.isNaN(ts) || ts < cutoff) continue;
+      if (rec.id === id) {
+        next.push({ id, lastLoginAt: now });
+        updated = true;
+      } else {
+        next.push(rec);
+      }
+    }
+    if (!updated) next.push({ id, lastLoginAt: now });
+    await saveFile({ records: next });
+  } catch (err) {
+    logger.debug?.('telemetry: recordLogin failed', {
+      error: err instanceof Error ? err.message : String(err),
+    });
+  }
+}
+
+/**
+ * Total distinct accounts seen in the 90-day retention window, plus those
+ * with a login in the last 7 days.
+ */
+export async function getLoginCounts(): Promise<{ total: number; active7d: number }> {
+  try {
+    const file = await loadFile();
+    const cutoff = Date.now() - RETENTION_MS;
+    const sevenAgo = Date.now() - SEVEN_DAYS_MS;
+    let total = 0;
+    let active7d = 0;
+    for (const rec of file.records) {
+      const ts = new Date(rec.lastLoginAt).getTime();
+      if (Number.isNaN(ts) || ts < cutoff) continue;
+      total++;
+      if (ts >= sevenAgo) active7d++;
+    }
+    return { total, active7d };
+  } catch {
+    return { total: 0, active7d: 0 };
+  }
+}

lib/telemetry/payload.ts

@@ -1,8 +1,8 @@
 import { readFileSync } from 'node:fs';
 import path from 'node:path';
 import { configManager } from '@/lib/admin/config-manager';
-import { logger } from '@/lib/logger';
 import { getInstanceId } from './state';
+import { getLoginCounts } from './login-tracker';
 import type {
   TelemetryPayload,
   TelemetryFeatures,
@@ -75,30 +75,10 @@ async function readFeatures(): Promise<TelemetryFeatures> {
   };
 }
 
-async function countAccounts(): Promise<{ total: number; active7d: number }> {
-  // Best-effort. If Stalwart's admin endpoint isn't reachable from here we
-  // return 0 / 0 - the heartbeat still fires.
-  try {
-    const adminUrl = process.env.STALWART_MGMT_URL || process.env.STALWART_ADMIN_URL;
-    const adminUser = process.env.STALWART_ADMIN_USER;
-    const adminPass = process.env.STALWART_ADMIN_PASSWORD;
-    if (!adminUrl || !adminUser || !adminPass) return { total: 0, active7d: 0 };
-    const auth = Buffer.from(`${adminUser}:${adminPass}`).toString('base64');
-    const res = await fetch(`${adminUrl.replace(/\/$/, '')}/api/principal?type=individual`, {
-      headers: { authorization: `Basic ${auth}` },
-      signal: AbortSignal.timeout(2000),
-    });
-    if (!res.ok) return { total: 0, active7d: 0 };
-    const body = await res.json() as { data?: { total?: number } };
-    const total = Number(body?.data?.total ?? 0);
-    return { total, active7d: total };
-  } catch (err) {
-    logger.debug?.('telemetry: account count probe failed', {
-      error: err instanceof Error ? err.message : String(err),
-    });
-    return { total: 0, active7d: 0 };
-  }
-}
+// Account counts come from the local login tracker, which records a per-
+// instance HMAC of every successful login plus the timestamp. Total = unique
+// identities seen in the last 90 days; active7d = identities with a login in
+// the last 7 days.
 
 async function countExtensions(): Promise<{ extensions: number; themes: number }> {
   try {
@@ -117,7 +97,7 @@ export async function buildPayload(): Promise<TelemetryPayload> {
   const instance_id = await getInstanceId();
   const { version, build } = readPackage();
   const features = await readFeatures();
-  const accounts = await countAccounts();
+  const accounts = await getLoginCounts();
   const exts = await countExtensions();
   const uptime_days = Math.min(
     365,