feat: add update-available detection

lib/version-check/sender.ts

@@ -0,0 +1,100 @@
+import { logger } from '@/lib/logger';
+import { disabledByEnv, effectiveEndpoint, loadState, saveState } from './state';
+import { fetchStatus } from './fetcher';
+import type { UpdateStatus } from './types';
+
+const HOUR_MS = 60 * 60 * 1000;
+const JITTER_MS = 5 * 60 * 1000;       // ± 5 min, keeps containers from syncing
+const FIRST_DELAY_MS = 30 * 1000;       // first check ~30s after boot
+const FAILURE_BACKOFF_MS = 15 * 60 * 1000; // after a failed fetch, retry in 15 min
+
+let currentTimer: NodeJS.Timeout | null = null;
+
+function jitteredDelay(base: number): number {
+  const j = (Math.random() * 2 - 1) * JITTER_MS;
+  return Math.max(60_000, base + j);
+}
+
+function getCurrentVersion(): string {
+  return (process.env.NEXT_PUBLIC_APP_VERSION || '').trim();
+}
+
+export async function checkOnce(opts?: { reason?: string }): Promise<{
+  ok: boolean;
+  status?: UpdateStatus;
+  error?: string;
+}> {
+  if (disabledByEnv()) return { ok: false, error: 'disabled by env' };
+
+  const state = await loadState();
+  const endpoint = effectiveEndpoint(state);
+  if (!endpoint) return { ok: false, error: 'endpoint blank' };
+
+  const current = getCurrentVersion();
+  if (!current) return { ok: false, error: 'current version unset' };
+
+  const now = new Date().toISOString();
+  const result = await fetchStatus(endpoint, current);
+
+  const next = await loadState();
+  next.lastCheckedAt = now;
+  if (result.ok) {
+    next.lastSuccessAt = now;
+    next.status = result.status;
+  }
+  await saveState(next);
+
+  logger.info('version-check: ran', {
+    ok: result.ok,
+    severity: result.ok ? result.status.severity : null,
+    reason: opts?.reason ?? 'scheduled',
+  });
+
+  if (result.ok) return { ok: true, status: result.status };
+  return { ok: false, error: result.error };
+}
+
+async function scheduleNext(delayMs: number): Promise<void> {
+  if (currentTimer) clearTimeout(currentTimer);
+  const at = new Date(Date.now() + delayMs).toISOString();
+  const state = await loadState();
+  state.nextScheduledAt = at;
+  await saveState(state);
+  currentTimer = setTimeout(() => { void tick(); }, delayMs);
+  // Don't keep the process alive just for this.
+  currentTimer.unref?.();
+}
+
+async function tick(): Promise<void> {
+  const result = await checkOnce({ reason: 'scheduled' });
+  const delay = result.ok ? jitteredDelay(HOUR_MS) : FAILURE_BACKOFF_MS;
+  await scheduleNext(delay);
+}
+
+// Idempotent — safe to call from instrumentation hot-reload in dev.
+export async function startScheduler(): Promise<void> {
+  if (disabledByEnv()) {
+    logger.info('version-check: scheduler not started (disabled by env)');
+    return;
+  }
+  const state = await loadState();
+  if (!effectiveEndpoint(state)) {
+    logger.info('version-check: scheduler not started (no endpoint)');
+    return;
+  }
+  // If a previous schedule was still in the future, honor it (don't blast on
+  // every restart). Cap at one hour so a wildly-in-the-future timestamp can't
+  // permanently silence the check.
+  let delay = FIRST_DELAY_MS;
+  if (state.nextScheduledAt) {
+    const remaining = new Date(state.nextScheduledAt).getTime() - Date.now();
+    if (remaining > 0) delay = Math.min(remaining, HOUR_MS + JITTER_MS);
+  }
+  await scheduleNext(delay);
+  logger.info('version-check: scheduler started', { nextInMs: delay });
+}
+
+export async function stopScheduler(): Promise<void> {
+  if (currentTimer) clearTimeout(currentTimer);
+  currentTimer = null;
+}