woodlot

An all-in-one JSON logging utility that supports ExpressJS HTTP logging, custom logging, provides multi-format output and an easy to use events API.

• Works as an HTTP logging middleware with ExpressJS
• Support for custom logging with different logging levels
• Provides log output in json format with request body/query params, headers and cookies
• Support for Apache common and combined log formats as output
• Multiple file stream support for log aggregation
• Simple to use events API
• Requires node >= 0.10

Installation

Using npm

npm install woodlot --save

Using yarn

yarn add woodlot

Usage

As an ExpressJS middleware

The woodlot middlewareLogger can be hooked into the existing ExpressJS middleware chain and can be used to log all HTTP requests.

Example -

var express = require('express');
var app = express();
var woodlot = require('woodlot').middlewareLogger;

app.use(woodlot({
    streams: ['./logs/app.log'],
    stdout: false,
    routes: {
        whitelist: ['/api', '/dashboard'],
        strictChecking: false
    },
    userAnalytics: {
        platform: true,
        country: true
    },
    format: {
        type: 'json',
        options: {
            cookies: true,
            headers: true,
            spacing: 4,
            separator: '\n'
        }
    }
}));

Options

streams {array} | required

This is a required option that specifies the file stream endpoints where the generated logs will be saved. You can specify multiple streams using this option.

stdout {boolean} | Default: true

It specifies whether the generated log entry should be logged to the standard output stream i.e. process.stdout or not.

routes {object}

This option is used with the woodlot middlewareLogger. It specifies all the routes (with checking mode) for which logging is to be enabled. By default, log entry is generated for all the routes.

whitelist {array}

This option is used with the routes option to specify the route whitelist.

strictChecking {boolean} | Default: false

This option is used with the routes option to specify the checking mode for the route whitelist.

routes: {
    whitelist: ['/api'],
    strictChecking: false
}

For the above example, setting it to false will enable logging for all routes that have api in them. Example - /api, /api/getUser, /api/getUser/all, /userapi etc.

Whereas, setting it to true will only enable logging for the /api route.

userAnalytics {object}

Use this option to add user details to your logs.

platform {boolean} | Default: false

Use this option with userAnalytics, to specify whether to include user platform info in the logs or not i.e. browser, browserVersion, os, and osVersion.

country {boolean} | Default: false

Use this option with userAnalytics, to specify whether to include user country info in the logs or not i.e. name and isoCode.

The userAnalytics option will add the following info to your logs -

"userAnalytics": {
    "browser": "Chrome",
    "browserVersion": "60.0.3112.90",
    "os": "Mac OS",
    "osVersion": "10.11.6",
    "country": {
        "name": "India",
        "isoCode": "IN"
    }
}

format {object}

This option sets the log output format and other settings related to that particular format.

type {string} | Default: 'json'

The default output format is json. The middlewareLogger supports two more formats - common and combined, which are Apache's access log formats.

The generated output log for each format is as follows -

json

{
    "responseTime": "4ms",
    "method": "GET",
    "url": "/api",
    "ip": "127.0.01",
    "body": {},
    "params": {},
    "query": {},
    "httpVersion": "1.1",
    "statusCode": 200,
    "timeStamp": "23/Apr/2017:20:46:01 +0000",
    "contentType": "text/html; charset=utf-8",
    "contentLength": "4",
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36",
    "referrer": null,
    "userAnalytics": {
        "browser": "Chrome",
        "browserVersion": "60.0.3112.90",
        "os": "Mac OS",
        "osVersion": "10.11.6",
        "country": {
            "name": "India",
            "isoCode": "IN"
        }
    },
    "headers": {
        "host": "localhost:8000",
        "connection": "keep-alive",
        "accept-encoding": "gzip, deflate, sdch, br",
        "accept-language": "en-US,en;q=0.8,la;q=0.6"
    },
    "cookies": {
        "userId": "zasd-167279192-asknbke-0684"
    }
}

json format supports logging of body params and cookies. If you wish to log them, please make sure to enable the bodyParser and cookieParser middlewares before woodlot.

common

127.0.01 - - [23/Apr/2017:20:47:28 +0000] "GET /api HTTP/1.1" 200 4

combined

127.0.01 - - [23/Apr/2017:20:48:10 +0000] "GET /api HTTP/1.1" 200 4 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36"

The timestamp generated in all logs is in ISO format.

options {object}

cookies {boolean} | Default: false

This option is to be used with the json format. It specifies whether you want to log request cookies or not.

Please make sure that the cookieParser middleware is enabled before woodlot, if this option is to be used.

headers {boolean} | Default: true

This option is to be used with the json format. It specifies whether you want to log request headers or not.

compact {boolean} | Default: false

This option is to be used with the json format. It specifies whether you want to log json as one line compact string.

NOTE spacing option will be ignored if this option is set to true.

spacing {string|number} | Default: \t

This option is to be used with the json format. It specifies the indentation for the generated log entry. You can specify a tab \t or numeric values 4, 8 for spaces.

separator {string} | Default: \n

This option can be used with any of the supported formats. It specfies the separator between two log entires. You can add a newline character \n, a whitespace or any other valid character.

Custom logging

The woodlot customLogger can be used to perform custom logging with different logging levels.

Example -

var express = require('express');
var app = express();
var woodlotCustomLogger = require('woodlot').customLogger;

var woodlot = new woodlotCustomLogger({
    streams: ['./logs/custom.log'],
    stdout: false,
    format: {
        type: 'json',
        options: {
            spacing: 4,
            separator: '\n'
        }
    }
});

app.get('/', function(req, res) {
    var id = 4533;
    woodlot.info('User id ' + id + ' accessed');
    return res.status(200).send({ userId: id });
});

Log levels

info

woodlot.info('Data sent successfully');

debug

woodlot.debug('Debugging main function');

warn

woodlot.warn('User Id is required');

err

woodlot.err('Server error occurred');

Options

streams {array} | required

See here.

stdout {boolean} | Default: true

See here.

format {object}

See here.

type {string} | Default: 'json'

The default output format is json. The customLogger supports one more format - text.

The generated output log for each format is as follows -

json

{
    "timeStamp": "23/Apr/2017:17:02:33 +0000",
    "message": "Data sent successfully",
    "level": "INFO"
}

text

INFO [23/Apr/2017:17:02:33 +0000]: "Data sent successfully"

options {object}

compact {boolean} | Default: false

This option is to be used with the json format. It specifies whether you want to log json as one line compact string.

NOTE spacing option will be ignored if this option is set to true.

spacing {string|number} | Default: \t

This option is to be used with the json format. It specifies the indentation for the generated log entry. You can specify a tab \t or numeric values 4, 8 for spaces.

separator {string} | Default: \n

This option can be used with any of the supported formats. It specfies the separator between two log entires. You can add a newline character \n, a whitespace or any other valid character.

Events

Woodlot emits events at various operations that can be used to track critical data.

Example -

var woodlotEvents = require('woodlot').events;

woodlotEvents.on('reqLog', function(log) {
     console.log('New log generated');
});

The returned log entry from each event will be of the same format as the one defined in the woodlot configuration.

middlewareLogger events

reqLog

This event is fired whenever a log entry is generated.

woodlotEvents.on('reqLog', function(log) {
    console.log('The following log entry was added - \n' + log);
});

:statusCode

This event is fired whenever a specific status code is returned from the request.

woodlotEvents.on('200', function(log) {
    console.log('Success!')
});

woodlotEvents.on('403', function(log) {
    console.log('Request forbidden!')
});

reqErr

This event is fired whenever an error is returned from the request.

All requests returning a status code of >=400 are considered to be errored. Please refer to the HTTP status codes guide for more info.

woodlotEvents.on('reqErr', function(log) {
    console.log('Errored!')
});

customLogger events

info

This event is fired whenever an info level log entry is generated.

woodlotEvents.on('info', function(log) {
    console.log('Info log - ' + log);
});

debug

This event is fired whenever a debug level log entry is generated.

woodlotEvents.on('debug', function(log) {
    console.log('Debug log - ' + log);
});

warn

This event is fired whenever a warn level log entry is generated.

woodlotEvents.on('warn', function(log) {
    console.log('Warn log - ' + log);
});

err

This event is fired whenever an err level log entry is generated.

woodlotEvents.on('err', function(log) {
    console.log('Error log - ' + log);
});

Contributors

Arun Michael Dsouza	Dhiraj Singh	Chen Li

Support

If you'd like to help support the development of the project, please consider backing me on Patreon -

License

MIT License

Copyright (c) 2017 AdPushup Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.