Log Level Management — Dynamic Log Level Management in Production

// Dynamic log level manager
class LogLevelManager {
  constructor(logger) {
    this.logger = logger;
    this.levels = {
      error: 0,
      warn: 1,
      info: 2,
      debug: 3,
      trace: 4
    };
    this.overrides = new Map();

    // Restore from Redis on startup
    this.restoreOverrides();
  }

  setLevel(service, component, level) {
    if (!this.levels[level]) throw new Error(`Invalid level: ${level}`);
    const key = `${service}:${component}`;
    this.overrides.set(key, level);

    // Persist override
    redis.set(`loglevel:${key}`, level, 'EX', 86400);

    return { service, component, level, expiresIn: '24h' };
  }

  getEffectiveLevel(service, component) {
    const override = this.overrides.get(`${service}:${component}`);
    if (override) return override;

    const serviceOverride = this.overrides.get(`${service}:*`);
    if (serviceOverride) return serviceOverride;

    return this.logger.level;
  }

  shouldLog(level, service, component) {
    return this.levels[level] <= this.levels[this.getEffectiveLevel(service, component)];
  }

  async restoreOverrides() {
    const keys = await redis.keys('loglevel:*');
    for (const key of keys) {
      const [_, service, component] = key.split(':');
      const level = await redis.get(key);
      this.overrides.set(`${service}:${component}`, level);
    }
  }

  getActiveOverrides() {
    return Array.from(this.overrides.entries()).map(([key, level]) => {
      const [service, component] = key.split(':');
      return { service, component, level };
    });
  }
}

// API endpoint
app.post('/admin/log-level', async (req, res) => {
  const { service, component, level } = req.body;
  const result = logManager.setLevel(service, component, level);
  res.json(result);
});