Crowlog - Async Context Plugin

This package is a plugin for the Crowlog logger. It allows to simply add context data to the logs using node async context. It's useful in http servers to add log context that follow the lifecycle of a request (like a request id or user id).

[!IMPORTANT] This plugin is only available environment that supports async_hooks like Node.js or cloudflare workers with compatibility flags.

Installation

// pnpm 
pnpm install @crowlog/logger @crowlog/async-context-plugin

// npm
npm install @crowlog/logger @crowlog/async-context-plugin

// yarn
yarn add @crowlog/logger @crowlog/async-context-plugin

Usage

Use the plugin by first creating a logger with the plugin:

import { createLogger } from '@crowlog/logger';
import { createAsyncContextPlugin, addLogContext, wrapWithLoggerContext } from '@crowlog/async-context-plugin';

const logger = createLogger({ namespace: 'my-app', plugins: [createAsyncContextPlugin()] });

// create a context, some initial context data can be added
wrapWithLoggerContext({ requestId: '123' }, () => {
  addLogContext({ userId: '123' });

  // logs within the context will have the requestId and userId
  logger.info('Hello world');
});

Examples

Hono JS

import { createMiddleware } from 'hono';
import { addLogContext, wrapWithLoggerContext } from '@crowlog/async-context-plugin';

const loggerMiddleware = createMiddleware(async (context, next) => {
  const requestId = getHeader({ context, name: 'x-request-id' }) ?? generateId();

  await wrapWithLoggerContext({ requestId }, next);
});

const authMiddleware = createMiddleware(async (context, next) => {
  const userId = /* get the user id from your auth layer */;

  addLogContext({ userId });

  await next();
});

import { Hono } from 'hono';
import { createLogger } from '@crowlog/logger';
import { createAsyncContextPlugin } from '@crowlog/async-context-plugin';

const app = new Hono();
const logger = createLogger({ namespace: 'my-app', plugins: [createAsyncContextPlugin()] });

app.use(loggerMiddleware);
app.use(authMiddleware);

app.get('/', (c) => {
  // logs will have the requestId and userId
  logger.info('Request received');

  return c.json({ message: 'Hello World' });
});

License

This project is licensed under the MIT License. See the LICENSE file for more information.

Credits

This project is crafted with ❤️ by Corentin Thomasset. If you find this project helpful, please consider supporting my work.