LogLayer

loglayer is a unified logger that routes logs to various logging libraries, cloud providers, files, and OpenTelemetry while providing a fluent API for specifying log messages, metadata and errors.

• For full documentation, read the docs.
• Older 4.x documentation

// Example using the Pino logging library with LogLayer
// You can also start out with a console logger and swap to another later!
import { LogLayer } from 'loglayer';
import { pino } from 'pino';
import { PinoTransport } from '@loglayer/transport-pino';
import { redactionPlugin } from '@loglayer/plugin-redaction';

const log = new LogLayer({
  // Multiple loggers can also be used at the same time. 
  transport: new PinoTransport({
    logger: pino()
  }),
  // Plugins modify log data before it's shipped to your logging library.
  plugins: [
    redactionPlugin({
      paths: ['password'],
      censor: '[REDACTED]',
    }),
  ],
  // Put context data in a specific field (default is flattened)
  contextFieldName: 'context',
  // Put metadata in a specific field (default is flattened)
  metadataFieldName: 'metadata',
})

// persisted data that is always included in logs
log.withContext({
   path: "/",
   reqId: "1234"
})

log.withPrefix("[my-app]")
  .withError(new Error('test'))
  // data that is included for this log entry only
  .withMetadata({ some: 'data', password: 'my-pass' })
  // Non-object data only (numbers and strings only)
  // this can be omitted to just log an object / error
  // by using .errorOnly() / .metadataOnly() instead of withError() / withMetadata()
  .info('my message')

{
   "level": 30,
   "time": 1735857465669,
   "msg": "[my-app] my message",
   "context": {
      "path": "/",
      "reqId": "1234",
   },
   "metadata": {
      "password": "[REDACTED]",
      "some": "data",
   },
   "err":{
      "type": "Error",
      "message": "test",
      "stack": "Error: test\n ..."
   }
}

Development Setup

This is a monorepo using pnpm for package management and turbo for build orchestration. If you're looking to contribute or work with the source code, follow these steps:

1. Clone the repository
2. Install dependencies:

   pnpm install

3. Build all packages:

   turbo build

Running Tests

To run tests for all packages, use the following command:

turbo test

Viewing docs

The docs use vitepress. To view the docs locally, run:

turbo docs:dev

Project Structure

loglayer/
├── docs/                         # Documentation (vitepress)
├── packages/
│   ├── core/                     # Core packages
│   │   ├── loglayer/             # Main LogLayer implementation
│   │   ├── plugin/               # Plugin system core
│   │   ├── transport/            # Transport system core
│   │   ├── shared/               # Shared utilities and types
│   │   └── tsconfig/             # Shared TypeScript configurations
│   ├── transports/               # Official transport implementations
│   └── plugins/                  # Official plugins

Contributing

We welcome contributions! Please see our Contributing Guide for details.

Documentation

For detailed documentation, visit https://loglayer.dev