🌲 Cabin is the best logger for JavaScript
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README.md

cabin

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Cabin is a logging/analytics service and middleware for the Browser, Node.js, Lad, Koa, Express, and Passport.
Need an alternative to Sentry, Airbrake, Papertrail, or Bugsnag? We did too! • Built by @niftylettuce and contributors

Cabin is in alpha development, join us in Slack. Our web-based dashboard will be available soon!

❤️ Love this project? Support @niftylettuce's FOSS on Patreon or PayPal 🦄

Table of Contents

Install

npm:

npm install cabin

yarn:

yarn add cabin

Quick Start

Logging

const Cabin = require('cabin');
const cabin = new Cabin();
cabin.info('hello world');
cabin.error(new Error('oops!'));

Route Middleware

app.use(cabin.middleware);

Usage

Don't want to configure this yourself? You can simply use Lad which has this all built-in for you.

Logging

Cabin exposes all log levels from the built-in logger (Axe) or whichever custom logger you pass.

Each log level should be invoked with two arguments message and meta.

  • message (String or Error) - this should be either a String or an Error object
  • meta (Object) - this is optional, and inherits properties from config.meta

See either the Node or Browser instructions below for further usage (e.g. route middleware).

Node

The examples below show how to use Cabin in combination with Axe, Signale logging utility (for development), Pino logging utility (for production), and how to add an accurate X-Response-Time response time metric to your logs and response headers automatically.

Koa

Don't want to configure this yourself? We highly recommend to use Lad instead of configuring this yourself as it has all of this pre-configured for you with best-practices. However if you already have an existing Koa based project the example below will sufficiently serve as a guide for implementation.

  1. Install required and recommended dependencies:

    npm install koa cabin signale pino response-time koa-connect express-request-id
  2. Implement the example code below (also found here):

    const Koa = require('koa');
    const Cabin = require('cabin');
    const Router = require('koa-router');
    const koaConnect = require('koa-connect');
    const responseTime = require('response-time');
    const requestId = require('express-request-id');
    const { Signale } = require('signale');
    const pino = require('pino')({
      customLevels: {
        log: 30
      }
    });
    
    const env = process.env.NODE_ENV || 'development';
    
    const app = new Koa();
    const router = new Router();
    const cabin = new Cabin({
      // (optional: your free API key from https://cabinjs.com)
      // key: 'YOUR-CABIN-API-KEY',
      axe: {
        logger: env === 'production' ? pino : new Signale()
      }
    });
    
    // adds `X-Response-Time` header to responses
    app.use(koaConnect(responseTime));
    
    // adds or re-uses `X-Request-Id` header
    app.use(koaConnect(requestId()));
    
    // use the cabin middleware (adds request-based logging and helpers)
    app.use(cabin.middleware);
    
    // add your user/session management middleware here (e.g. passport)
    // ...
    
    // an example home page route
    router.get('/', ctx => {
      ctx.logger.info('someone visited the home page');
      ctx.body = 'hello world';
    });
    
    // this assumes that you are using passport which
    // exposes `ctx.logout` to log out the logged in user
    router.get('/logout', ctx => {
      ctx.logger.warn('Logged out');
      ctx.logout();
      ctx.redirect('/');
    });
    
    app.use(router.routes());
    app.use(router.allowedMethods());
    
    app.listen(3000, () => {
      cabin.info('app started');
    });
  3. See Koa convenience methods below for helper utilities you can use while writing code.

Express

  1. Install required and recommended dependencies:

    npm install koa cabin signale pino response-time express-request-id
  2. Implement the example code below (also found here):

    const express = require('express');
    const Cabin = require('cabin');
    const responseTime = require('response-time');
    const requestId = require('express-request-id');
    const { Signale } = require('signale');
    const pino = require('pino')({
      customLevels: {
        log: 30
      }
    });
    
    const env = process.env.NODE_ENV || 'development';
    
    const app = express();
    const cabin = new Cabin({
      // (optional: your free API key from https://cabinjs.com)
      // key: 'YOUR-CABIN-API-KEY',
      axe: {
        logger: env === 'production' ? pino : new Signale()
      }
    });
    
    // adds `X-Response-Time` header to responses
    app.use(responseTime());
    
    // adds or re-uses `X-Request-Id` header
    app.use(requestId());
    
    // use the cabin middleware (adds request-based logging and helpers)
    app.use(cabin.middleware);
    
    // add your user/session management middleware here (e.g. passport)
    // ...
    
    // an example home page route
    app.get('/', (req, res) => {
      req.logger.info('someone visited the home page');
      res.send('hello world');
    });
    
    // this assumes that you are using passport which
    // exposes `req.logout` to log out the logged in user
    app.get('/logout', (req, res) => {
      req.logger.warn('Logged out');
      req.logout();
      res.redirect('/');
    });
    
    app.listen(3000, () => {
      cabin.info('app started');
    });
  3. See Express convenience methods below for helper utilities you can use while writing code.

Convenience Methods

In order to easily interact and use the logger utility function exposed by app.use(cabin.middleware), we expose convenient helper methods in Express and Koa:

Express
  • req.log
  • req.logger
  • res.log
  • res.logger
Koa
  • ctx.log
  • ctx.logger
  • ctx.req.log
  • ctx.req.logger
  • ctx.res.log
  • ctx.res.logger
  • ctx.request.log
  • ctx.request.logger
  • ctx.response.log
  • ctx.response.logger

Browser

VanillaJS

This is the solution for you if you're just using <script> tags everywhere!

<script src="https://unpkg.com/cabin"></script>
<script type="text/javascript">
  (function() {
    var cabin = new Cabin({ key: 'YOUR-CABIN-API-KEY', capture: true });
    cabin.setUser({
      id: '1',
      email: 'niftylettuce@gmail.com',
      full_name: 'niftylettuce'
    });
    cabin.info('viewed docs');
  })();
</script>

Bundler

This assumes you are using browserify, webpack, rollup, or another bundler.

const Cabin = require('cabin');

const cabin = new Cabin({ key: 'YOUR-CABIN-API-KEY' });

cabin.setUser({
  id: '1',
  email: 'niftylettuce@gmail.com',
  full_name: 'niftylettuce'
});

cabin.info('viewed docs');

Automatic Request Logging

Server

For server-side logging of requests, the Cabin middleware cabin.middleware will automatically log requests for you upon completion. Just make sure you are using express-request-id middleware like in the examples above in order for the X-Request-Id header to be set (and re-used if already exists, e.g. generated from client side as in below). If you're using Koa make sure to wrap with koaConnect as shown in the examples above.

Browser

We strongly recommend that you implement one of the following code snippets with xhook (for either VanillaJS or Bundler approaches) so that all your XHR requests have a X-Request-Id automatically added (which in turn ensures both client and server have matching request ID's). Imagine how awesome your logs will be when you can see the full trace starting with the client!

Pug

You can do a similar approach with React, EJS, or another templating language.

script(src='https://unpkg.com/xhook')
script(src='https://unpkg.com/cabin')
//- TODO: note this won't work until issue #123 is resolved
//- <https://github.com/ericelliott/cuid/issues/123>
//- script(src='https://unpkg.com/cuid/dist/cuid.min.js')
script.
  (function() {
    var cabin = new Cabin({ key: 'YOUR-CABIN-API-KEY', capture: true });
    cabin.setUser({
      id: '1',
      email: 'niftylettuce@gmail.com',
      full_name: 'niftylettuce'
    });
    xhook.before(function(req) {
      // once the above issue is fixed we can uncomment this
      // if (!req.headers['X-Request-Id'])
      //   req.headers['X-Request-Id'] = cuid();
      cabin.info('xhr', cabin.parseRequest(req));
    });
  })();
Bundler

npm:

npm install cabin xhook cuid

yarn:

yarn add cabin xhook cuid
const Cabin = require('cabin');
const xhook = require('xhook');
const cuid = require('cuid');

const cabin = new Cabin({ key: 'YOUR-CABIN-API-KEY', capture: true });

cabin.setUser({
  id: '1',
  email: 'niftylettuce@gmail.com',
  full_name: 'niftylettuce'
});

xhook.before(req => {
  if (!req.headers['X-Request-Id'])
    req.headers['X-Request-Id'] = cuid();
  cabin.info('xhr', cabin.parseRequest(req));
});

Stack Traces and Error Handling

We leave it up to you to decide how you wish to handle stack traces and errors, but we've documented our approaches for Node and Browser environments below.

Node

If you're using Lad, then you don't need to worry about error handling, as it's built-in (complete with graceful reloading, even for database connections).

However you can otherwise use a tool such as uncaught to listen for errors, or bind purely to process events emitted as shown below:

const Cabin = require('cabin');

const cabin = new Cabin({ key: 'YOUR-CABIN-API-KEY' });

process.on('uncaughtException', err => {
  cabin.error(err);
  process.exit(1);
});

process.on('unhandledRejection', err => {
  cabin.error(err);
});

Browser

Since cross-browser support is very limited and unstandardized for errors and stack traces, we highly recommend to use either StackTrace or TraceKit as documented below.

StackTrace

We recommend to use StackTrace instead of TraceKit as it is a more modern alternative and provides much similarity between your Browser and your Node errors (stackframes are basically similar to representations in Gecko and V8, aka the ones you get with Node).

It does require you to have a polyfill if you're using it in the browser (only if you're supporting browsers that don't support standardized Promises/JSON). You'll basically need es6-promise and json3 polyfills for browsers you wish to support that don't have them. The example below shows you how to polyfill, don't worry! You can reference Caniuse data on Promises and JSON respectively if you need.

The example below demonstrates using StackTrace with uncaught to catch global errors below, but note that uncaught only supports IE11+, so if you need < IE11 support you probably should use TraceKit instead.

If you're curious why it won't work in IE11, please see this great documentation on JavaScript errors cross-browser here - in particular the section on "No Error object provided".

<script src="https://unpkg.com/stacktrace-js"></script>
<!-- Use this instead of the above if you need to polyfill for IE11 support -->
<!-- <script src="https://unpkg.com/stacktrace-js/dist/stacktrace-with-promises-and-json-polyfills.js"></script> -->

<script src="https://unpkg.com/uncaught"></script>
<script src="https://unpkg.com/cabin"></script>

<script type="text/javascript">
  (function() {
    var cabin = new Cabin({ key: 'YOUR-CABIN-API-KEY' });
    uncaught.start();
    uncaught.addListener(function(err) {
      // this will transform the error's `stack` property
      // to be consistently similar to Gecko and V8 stackframes
      StackTrace.fromError(err)
        .then(function(stackframes) {
          // StackTrace has a convenient `report` method however
          // we want to send along more information than just this
          // <https://github.com/stacktracejs/stacktrace.js#stacktracereportstackframes-url-message-requestoptions--promisestring>
          // StackTrace.report(stackframes, endpoint, err.message);
          // however we want to leave it up to the logger to
          // report and record the error
          err.stack = stackframes;
          cabin.error(err);
        })
        .catch(function(_err) {
          // log both original and new error
          cabin.error(err);
          cabin.error(_err);
        });
    });
  })();
</script>
TraceKit

This is a legacy stack trace package with support for very old browsers. You can view TraceKit's full documentation here.

It is widely used by logging services and seems to be the most popular tool. Note that in the example code below, you will notice a repetitive pattern you'll encounter of wrapping code with a try and catch block. Don't worry, because if you're using webpack or gulp, you can easily wrap your bundled files with try and catch blocks! See Automatic Try Catch Wrapping below.

<script src="https://unpkg.com/tracekit"></script>
<script src="https://unpkg.com/cabin"></script>

<script type="text/javascript">
  (function() {
    var cabin = new Cabin({ key: 'YOUR-CABIN-API-KEY' });

    // when `TraceKit.report` gets called
    // this subscribe function will be invoked
    TraceKit.report.subscribe(function(err) {
      cabin.error(err);
    });

    try {
      // put all your application code in a global try/catch block
      //
      // ...
      //
      // maybe you throw an error in here by accident? it'll get caught!
      // throw new Error('oops');
    } catch (err) {
      TraceKit.report(err);
    }
  })();
</script>
Automatic Try Catch Wrapping
Gulp
npm install -D gulp-wrap
const wrap = require('gulp-wrap');

gulp.src('./asset.js')
  .pipe(wrap(`
    try {
      <%= contents %>
    } catch (err) {
      TraceKit.report(err);
    }
  `))
  .pipe(gulp.dest('./dist'));
Webpack
npm install -D wrapper-webpack-plugin
const WrapperPlugin = require('wrapper-webpack-plugin');

module.exports = {
  // other webpack config here
  plugins: [
    new WrapperPlugin({
      test: /\.js$/, // only wrap output of bundle files with '.js' extension
      header: 'try {\n',
      footer: '\n} catch (err) {\n  TraceKit.report(err);\n}'
    })
  ]
};

Display Metadata and Stack Traces

Under the hood, Cabin uses Axe which provides us with several options, including one to show metadata (e.g. request headers, body, and user) and another to show stack traces for errors.

You can pass these options through the axe option (see Options below), or you could pass environment flags when you need to.

By default, Axe does not output any metadata and only outputs stack traces in non-production environments.

Metadata

To hide metadata, pass a falsey value for the process environment variable SHOW_META.

(e.g. SHOW_META=0 or SHOW_META=false before running your script, such as SHOW_META=false node app).

Similarly if you pass a truthy value of 1 or true it will show metadata (which is the default behavior).

Stack Traces

To hide stack traces, pass a falsey value for the process environment variable SHOW_STACK.

(e.g. SHOW_STACK=0 or SHOW_STACK=false before running your script, such as SHOW_STACK=false node app).

Similarly if you pass a truthy value of 1 or true it will show metadata (which is the default behavior).

Options

  • key (String) - defaults to an empty string, this is where you put your Cabin API key, which you can get for free at Cabin
  • axe (Object) - defaults to an empty Object {}, but you can pass options here for Axe
  • logger (Object) - if you have a custom logger you wish to use instead of Axe, but note that Axe accepts a logger option, so you should use that instead, see Axe docs for more info.
  • meta (Object) - defaults to an empty object - this will get passed as metadata (e.g. you could set a custom meta.user object here for every request).
  • userFields (Array) - defaults to [ 'id', 'email', 'full_name', 'ip_address'] - these are the default fields to store from a parsed user object from parse-request (see Metadata below).
  • fields (Array) - defaults to an empty Array [] - these are the default fields to store from a parsed user object, this is consumed by parse-err (see Metadata below).
  • message (String) - defaults to a generic log output (see src/index.js's message option) - this is used by cabin.middleware when requests finish, it will utilize logger to output an error, warn, or info level log based off the status code
  • templateSettings (Object) - defaults to variable interpolation with {{ var }} vs <%= var %> (see Lodash template docs)

Metadata

We use the packages parse-request and parse-err to populate a metadata object meta with properties request, user, and err.

The request and user objects contains parsed header, cookie, body, and user information (including IP) via parse-request. The err object contains parsed error fields including non-enumerable properties (which are normally not visible) on Error objects (this uses parse-err under the hood).

If a logged in user is detected (e.g. if you're using Passport), then a meta.user property is automatically created for you (depending on userFields option passed to Cabin, see Options above).

Related

  • koa-better-error-handler - A better error-handler for Lad and Koa. Makes ctx.throw awesome!
  • axe - Logging utility for Node and Browser environments. Chop up your logs!
  • lad - Scaffold a Koa webapp and API framework for Node.js
  • lass - Scaffold a modern boilerplate for Node.js
  • lipo - Free image manipulation API service built on top of Sharp

Contributors

Name Website
Nick Baugh http://niftylettuce.com/

Trademark Notice

Axe, Lad, Lass, Cabin, Lipo, and their respective logos are trademarks of Niftylettuce LLC. These trademarks may not be reproduced, distributed, transmitted, or otherwise used, except with the prior written permission of Niftylettuce LLC. If you are seeking permission to use these trademarks, then please contact us.

License

MIT © Nick Baugh

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