Getting Started #

Kuzzle Logger is the logger of Kuzzle and of its applications. It is built on Pino: entries are JSON lines, written to one or more destinations (stdout, a file, Loki, Elasticsearch) configured with presets.

Which guide do I need? #

In a Kuzzle application #

Kuzzle already uses Kuzzle Logger: app.log is a Kuzzle Logger. Its destinations are set by the server.appLogs section of the Kuzzle configuration (.kuzzlerc), which takes the same options as the KuzzleLogger constructor.

For example, to write to stdout and to Loki:

{
  "server": {
    "appLogs": {
      "level": "info",
      "serviceName": "my-app",
      "transport": {
        "targets": [
          { "preset": "stdout" },
          {
            "preset": "loki",
            "presetOptions": { "host": "http://loki:3100" }
          }
        ]
      }
    }
  }
}

The same can be set with environment variables, e.g. kuzzle_server__appLogs__serviceName=my-app.

Then log with app.log:

app.log.info('Application started');
app.log.error({ err: error, assetId }, 'Failed to update the asset');

const mqttLogger = app.log.child('mqtt'); // namespace "kuzzle:app:mqtt"

In a Node service #

npm install kuzzle-logger

import { KuzzleLogger } from 'kuzzle-logger';

const logger = new KuzzleLogger({
  serviceName: 'my-service',
  transport: { preset: 'stdout' },
});

logger.info('Hello, world!');
logger.debug({ userId: '123', action: 'login' }, 'User login attempt');
logger.error(new Error('Something went wrong'), 'Error occurred');

Without transport, entries are written to stdout. The stdout preset pretty-prints them when NODE_ENV is development or not set: install pino-pretty for that, or set NODE_ENV=production to get JSON lines.

Entry points #