Logging

Toast uses structured logging with Pino.

The logger contract and default factory now live in @toast/core:

Logger interface → packages/core/src/logger.ts
createLogger() → packages/core/src/logger.factory.ts

The API composition root creates the logger at startup and passes it down through dependency injection.

Basic pattern

Application code should receive a Logger through dependencies rather than importing a singleton.

export function createSomethingService(deps: { logger: Logger }) {
  return {
    async doWork() {
      deps.logger.info({ resource: 'something' }, 'Starting work');
    },
  };
}

Use structured fields, not string interpolation:

logger.info({ userId, contentId, action: 'publish' }, 'Content published');

Logger setup

The composition root creates the logger from validated config:

import { createLogger } from '@toast/core';

const logger = createLogger(config.logger);

Standard fields

Include these when relevant:

Field	Meaning
`requestId`	request correlation
`siteId`	tenant scope
`userId`	authenticated actor
`err`	error object
`duration_ms`	timing information

Sensitive data

Never log:

passwords
tokens or API keys
full session credentials
full payment data

Prefer redacted or partial values if context is needed.

// Bad
logger.info({ password, token }, 'Login attempt');

// Better
logger.info({ emailDomain: email.split('@')[1] }, 'Login attempt');

Request logging

HTTP requests are logged by middleware. Route and service code should add extra logs only when they provide debugging value beyond the standard request record.

Environment behavior

Environment	Output
Development	pretty-printed logs
Production	JSON to stdout

Use LOG_LEVEL to control verbosity.