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Graceful Shutdown

Graceful shutdown is mandatory for all applications (development and production) so that pending logs are flushed and resources released when the process stops.

Why it matters​

Without handling SIGTERM/SIGINT and calling syntropyLog.shutdown():

  • Lost logs — Entries still in the pipeline may never be written.
  • Unclean exit — Transports may not flush or close.
  • Kubernetes/containers — The process can be killed before cleanup if shutdown is not handled.

Required pattern​

  1. Subscribe to ready and error before calling init().
  2. Call init(config) and wait for ready (or handle error).
  3. On process exit (SIGTERM, SIGINT, or application shutdown), call await syntropyLog.shutdown() and then exit.

Boilerplate​

import { syntropyLog } from 'syntropylog';

export async function initializeSyntropyLog(config) {
  return new Promise((resolve, reject) => {
    syntropyLog.on('ready', () => resolve());
    syntropyLog.on('error', (err) => reject(err));
    syntropyLog.init(config);
  });
}

export async function gracefulShutdown() {
  try {
    await syntropyLog.shutdown();
  } catch (err) {
    console.error('Shutdown error:', err);
  }
}

process.on('SIGINT', async () => {
  await gracefulShutdown();
  process.exit(0);
});
process.on('SIGTERM', async () => {
  await gracefulShutdown();
  process.exit(0);
});

What shutdown does​

  • Flushes transports — Pending log entries are written before the process exits.
  • Releases resources — Transports and internal state are cleaned up.
  • Ordered exit — Avoids losing logs or leaving connections open.

Usage​

Initialize at startup and let the signal handlers call gracefulShutdown() when the process receives SIGTERM or SIGINT (e.g. Ctrl+C or Kubernetes termination). No need to call gracefulShutdown() manually unless you have a custom exit path.

Testing​

# Development: press Ctrl+C and confirm you see shutdown messages and logs flushed
# Production: send SIGTERM
kill -TERM <pid>

See also​