Function shutdown

apps/api/src/utils/graceful-shutdown.ts:30–139

(
  fastify: FastifyInstance,
  signal: string,
  exitCode = 0
)

// Graceful shutdown handler
export async function shutdown(
  fastify: FastifyInstance,
  signal: string,
  exitCode = 0
) {
  if (isShuttingDown()) {
    logger.warn({ signal }, 'Shutdown already in progress, ignoring signal');
    return;
  }

  logger.info({ signal }, 'Starting graceful shutdown');

  setShuttingDown(true);

  // Hard deadline: if any close() below hangs (Kafka producer stuck,
  // Redis still connecting, BullMQ wait), force-exit before Docker's
  // stop_grace_period elapses. Without this the container can sit in
  // "Stopping" until SIGKILL (exit 137) and look like a real crash.
  const forceExitMs = Number(process.env.SHUTDOWN_FORCE_EXIT_MS || '15000');
  const forceExit = setTimeout(() => {
    logger.error(
      { signal, forceExitMs },
      'Graceful shutdown timed out — forcing exit',
    );
    process.exit(exitCode);
  }, forceExitMs);
  forceExit.unref();

  // Step 1: Wait for load balancer to stop sending traffic (matches preStop sleep)
  const gracePeriod = Number(process.env.SHUTDOWN_GRACE_PERIOD_MS || '5000');
  await new Promise((resolve) => setTimeout(resolve, gracePeriod));

  // Step 2: Close Fastify to drain in-flight requests
  try {
    await fastify.close();
    logger.info('Fastify server closed');
  } catch (error) {
    logger.error({ err: error }, 'Error closing Fastify server');
  }

  // Step 3: Destroy MCP sessions
  try {
    await mcpSessionManager.destroy();
    logger.info('MCP sessions closed');
  } catch (error) {
    logger.error({ err: error }, 'Error closing MCP sessions');
  }

  // Step 4: Close database connections
  try {
    await db.$disconnect();
    logger.info('Database connection closed');
  } catch (error) {
    logger.error({ err: error }, 'Error closing database connection');
  }

  // Step 5: Close ClickHouse connections
  try {