perfect-logger

The Perfect-Logger library exported as Node.js modules. With Perfect-Logger you can improve your application's logs

License

Highlights

• Easy to use
• Configurable
• Write log events to file
• Automatic log switching to avoid huge log files
• Custom log codes with log levels
• Log event call back support
• Colored terminal output

Installation

Using npm:

npm i perfect-logger

In Node.JS

// Load the perfect-logger module
let logger = require('perfect-logger');

// Configure Settings
logger.initialize('FrontEndDriver', {
    logLevelFile: 0,                    // Log level for file
    logLevelConsole: 0,                 // Log level for STDOUT/STDERR
    logDirectory: 'logs/',              // Log directory
    customBannerHeaders: 'This is a custom banner'  // Custom Log Banner
});

// Use
logger.info("This is an information");
logger.warn("This is a warning");
logger.crit("This is a critical message");
logger.debug('Wassup', {eyes: 2, feet: 2, hands: 2, eyeColor: 'blue'});
logger.info('Wassup', {eyes: 2, feet: 2, hands: 2, eyeColor: 'blue'});
logger.warn('Wassup', {eyes: 2, feet: 2, hands: 2, eyeColor: 'blue'});
logger.crit('Wassup', {eyes: 2, feet: 2, hands: 2, eyeColor: 'blue'});

Sample Terminal Output

 2020/02/21 | 18:26:00 | INFO | This is an information 
 2020/02/21 | 18:26:00 | WARN | This is a warning 
 2020/02/21 | 18:26:00 | CRIT | This is a critical message 
 2020/02/21 | 18:26:00 | DEBUG | Wassup 
 2020/02/21 | 18:26:00 | INFO | Wassup 
 2020/02/21 | 18:26:00 | WARN | Wassup 
 2020/02/21 | 18:26:00 | CRIT | Wassup

Sample Log File

***************************************************************************************************
*** 
*** This is a custom banner
*** 
***************************************************************************************************
*** 
*** Module Name          : FrontEndDriver
*** Project Name         : perfect-logger
*** Version              : 1.6.1
*** Configured Timezone  : Asia/Colombo
*** 
***************************************************************************************************
*** 
*** Log Number           : #1
*** Process Start Time   : 2/21/2020, 6:28:33 PM
*** Log Start Time       : 2/21/2020, 6:28:33 PM
*** Log Level            : 0
*** Continuing From      : None
*** 
***************************************************************************************************
*** 
*** Hostname             : XS3
*** OS Release           : 4.15.0-50-generic
*** Platform             : linux
*** NodeJS Version       : 8.17.0
*** OpenSSL Version      : 1.0.2s
*** 
***************************************************************************************************
*** 
*** DEPENDENT NPM PACKAGE DETAILS
*** 
*** [email protected] /home/sulochana/Documents/perfect-logger
*** ├── [email protected]
*** ├── [email protected]
*** ├── [email protected]
*** ├── [email protected]
*** └── [email protected]
*** 
*** 
***************************************************************************************************
2020/02/21 | 18:28:35 | INFO | This is an information
2020/02/21 | 18:28:35 | WARN | This is a warning
2020/02/21 | 18:28:35 | CRIT | This is a critical message
2020/02/21 | 18:28:35 | DEBUG | Wassup
[61]~ {
[61]~     "eyes": 2,
[61]~     "feet": 2,
[61]~     "hands": 2,
[61]~     "eyeColor": "blue"
[61]~ }
2020/02/21 | 18:28:35 | INFO | Wassup
[BQ]~ {
[BQ]~     "eyes": 2,
[BQ]~     "feet": 2,
[BQ]~     "hands": 2,
[BQ]~     "eyeColor": "blue"
[BQ]~ }
2020/02/21 | 18:28:35 | WARN | Wassup
[A8]~ {
[A8]~     "eyes": 2,
[A8]~     "feet": 2,
[A8]~     "hands": 2,
[A8]~     "eyeColor": "blue"
[A8]~ }
2020/02/21 | 18:28:35 | CRIT | Wassup
[KQ]~ {
[KQ]~     "eyes": 2,
[KQ]~     "feet": 2,
[KQ]~     "hands": 2,
[KQ]~     "eyeColor": "blue"
[KQ]~ }

Configuration Options

Configuration options needs to passed during the initialization. All these options are optional. Example

logger.initialize('ApplicationName', {
    logLevelFile: 0,                    // Log level for file
    logLevelConsole: 0,                 // Log level for STDOUT/STDERR
    logDirectory: 'logs/',              // Log directory
    customBannerHeaders: 'This is a custom banner'  // Custom Log Banner
});

Log Level

Log levels margins are as follow. You may declare your own log codes within the range -1 <= logLevel <= 10

DISABLED: -1
DEBUG: 0
INFO: 4
WARNING: 8
CRITICAL: 10

Log File

The log file will be saved as <ApplicationName>.log in the current working directory. Any existing log file with the same name will be renamed to following format <ApplicationName>.<ProcessID>.<ProcessStartTime>.log. Therefore the log file of the currently running process is always <ApplicationName>.log. You can change the log directory using the following option

logDirectory: './ApplicationLogs'

Sets the log level for the file output. The default value is 0 (LOG_LEVEL_DEBUG). Setting log level to -1 or any negative number will disable the log file.

logLevelFile: 0

Setting a maximum log file size will allow you to switch to new log file when the file size limit is reached. This is usefull to split log files. You must provide the size limit in Bytes.

maximumLogFieSize: 102400000

You can add a custom banner to log file

customBannerHeaders: 'This is a custom banner'

Console Log

Set the log level for the console output. The default value is 4 (LOG_LEVEL_INFO). Setting log level to -1 or any negative number will disable the console output.

logLevelConsole: 0

Callback

You can set a callback function whenever a log event is fired. This callback function should accept on parameter.

function myCallbackFunction(obj) {
    console.log('CALLBACK OUTPUT:', obj);
}

logger.initialize('FrontEndDriver', {
    callbackLogEvent: myCallbackFunction
});

The object passed into the function will be in following example format

{
    alias: 'info',
    message: 'Sample log message',
    code: 'INFO',
    color: 'red',
    logLevel: 4,
    time: '20:05:49',
    date: '2020/02/21',
    object: {}
}

Set the log level for the callback. The default value is 0 (LOG_LEVEL_DEBUG). Setting log level to -1 or any negative number will disable the callback.

logLevelCallback: 0

Timezone

You can change the logging timezone with the following option. Default timezone is UTC You can find a list of TimeZones here : https://timezonedb.com/time-zones

timezone: 'Asia/Colombo'

Development Mode

You can enable development with the following option. This will maintain a single log file.

developmentMode: true

Help and Support

For any queries drop an email to [email protected]