node-file-logger

v0.9.5

Published

3 years ago

A simple logger for logging exceptions and error details in log files.

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log logger file logger error logger exception handling logging file logging

Node File Logger

A simple logger for logging exceptions and error details in a log file.

  _   _           _        _____ _ _        _                                
 | \ | | ___   __| | ___  |  ___(_) | ___  | |    ___   __ _  __ _  ___ _ __ 
 |  \| |/ _ \ / _` |/ _ \ | |_  | | |/ _ \ | |   / _ \ / _` |/ _` |/ _ \ '__|
 | |\  | (_) | (_| |  __/ |  _| | | |  __/ | |__| (_) | (_| | (_| |  __/ |   
 |_| \_|\___/ \__,_|\___| |_|   |_|_|\___| |_____\___/ \__, |\__, |\___|_|   
                                                       |___/ |___/

Docs & Features

Dependencies

moment.js moment-timezone.js node-stringify.js

Suports all logging levels

DEBUG: The DEBUG Level designates fine-grained informational events that are most useful to debug an application.
TRACE: The TRACE Level designates finer-grained informational events than the DEBUG
INFO: The INFO level designates informational messages that highlight the progress of the application at coarse-grained level.
WARN: The WARN level designates potentially harmful situations.
ERROR: The ERROR level designates error events that might still allow the application to continue running.
FATAL: The FATAL level designates very severe error events that will presumably lead the application to abort.

Create date-wise log files

It has an option to create a new log file for the current date which will be named like YYYY-MM-DD-log.log

Extras

Allows logging the service name & method name
Allows logging a short error message and an entire error object (optional)
Error objects are stringified and then logged to the log file

Has a callback

It allows you to run a callback after the logging process.

Steps to use

Installation

npm install node-file-logger --save

Create instance of Node file logger

// Ceate an instance of node file logger
const log = require('node-file-logger');
log.SetUserOptions(options); // Options are optional

Using options

// It is recommended to set options in a separate module and include it in the code
// Everything in the example below are default values
const options = {
  timeZone: 'America/Los_Angeles',
  folderPath: './logs/',      
  dateBasedFileNaming: true,
  // Required only if dateBasedFileNaming is set to false
  fileName: 'All_Logs',   
  // Required only if dateBasedFileNaming is set to true
  fileNamePrefix: 'Logs_',
  fileNameSuffix: '',
  fileNameExtension: '.log',     
  
  dateFormat: 'YYYY-MM-DD',
  timeFormat: 'HH:mm:ss.SSS',
  logLevel: 'debug',
  onlyFileLogging: true
}

// Note: If you set dateBasedFileNaming to false, then a log file will be created at the folder path with the provided fileName.
// If set to true then a logfile will be created with the name <fileName> provided in the options

log.SetUserOptions(options);

Examples

Simple logging to a file with date-based log file naming

const options = {
  folderPath: './logs/',
  dateBasedFileNaming: true,
  fileNamePrefix: 'DailyLogs_',
  fileNameExtension: '.log',    
  dateFormat: 'YYYY_MM_D',
  timeFormat: 'h:mm:ss A',
}

const log = require('node-file-logger');
log.SetUserOptions(options);

// Log a simple error message
log.Info('Some informational log message');

// *****************************************************
// Ouput in Logfile: 
// File name : ./logs/Logs_2018_02_23.log
// 5:52:28 PM | Info | Some informational log message
// *****************************************************

// Log an error message with service and method names
log.Error('Something has failed!', 'Some service', 'Some method');

// *****************************************************
// Ouput in Logfile: 
// File name : ./logs/Logs_2018_02_23.log
// 5:52:28 PM | Error | Service: Some service | Method: Some method | Some error message
// *****************************************************

// Log an fatal error message with service and method names and error object
log.Fatal('Something has failed!', 'Some service', 'Some method', errorObj);

// *****************************************************
// Ouput in Logfile: 
// File name : ./logs/Logs_2018_02_23.log
// 5:52:28 PM | Fatal | Service: Some service | Method: Some method | Something is broken
{
  unhandledException: Something serious has happened
}
// *****************************************************

// Log an error message with callback
log.Info('Something has failed!', null, null, null, function() {
  // Do something
});

Simple logging to a file without date-based file naming

const options = {
  folderPath: './logs/',
  dateBasedFileNaming: false,
  fileName: 'All_Logs.log', 
  dateFormat: 'YYYY_MM_D',
  timeFormat: 'h:mm:ss A',
}

const log = require('node-file-logger');
log.SetUserOptions(options);

// Log a simple error message
log.Info('Some informational log message');


// *****************************************************
// Ouput in Logfile: 
// File name : ./logs/All_Logs.log
// 2018_02_23 5:52:28 PM | Info | Some informational log message
// *****************************************************

API Reference

Methods:

SetUserOptions()

Sets user options for node file logger

| Parameter | Description | Datatype | Optional | | --------- |-------------| ---------| -------- | | object | Configuration Object | object | no |

Details of the configuration object

| Parameter | Description | Datatype | Default Value | | --------- |-------------| ---------| -------- | | folderPath | Path of the folder where log file will be saved | string | ./logs/ | | dateBasedFileNaming | If set to true, date based file naming standard will be followed for log file | boolean |true | | fileName | Needed in case of single log file, where dateBasedFileNaming is set to false | string | All_Logs | | fileNamePrefix | Log file name prefix | string | Logs_ | | fileNameSuffix | Log file name suffix | string | '' | | fileNameExtension | Log file name extension | string | .log | | dateFormat | Date format for timestamp logging | string | YYYY-MM-DD | | timeFormat | Time format for timestamp logging | string | HH:mm:ss.SSS | | logLevel | Allowed values - debug, prod, prod-trace (Details below) | string | debug | | onlyFileLogging | If set to false then messages are logged to console as well | boolean | true |

Details of log levels

'prod' and 'prod-trace' levels are suitable for production releases

| Log level name | Description | | --------- |-------------| | debug | All log level messages are logged | | prod | Only 'warn', 'info', 'error' and 'fatal' messages are logged. 'debug' and 'trace' messages are not logged. | | prod-trace | Only 'debug' messages are not logged. All the others are logged. |

Debug()

Logs a debug message in the log file

| Parameter | Description | Datatype | Optional | | --------- |-------------| ---------| -------- | | errorMessage | Error message to be logged in the file | string | no | | serviceName | Service name from which info was logged | string | yes | | methodName | Method name from which info was logged | string | yes | | errorObj | Error object that needs to be logged | object | yes | | callback | Callback method that is called after error logging (may return an error) | function | yes |

Trace()

Logs a trace message in the log file

Info()

Logs a informational message in the log file

Warn()

Logs a warning message in the log file

Error()

Logs a error message in the log file

Fatal()

Logs a fatal error message in the log file

Log()

Used to log any kind of log message in the log file (Custom Log level)

| Parameter | Description | Datatype | Optional | | --------- |-------------| ---------| -------- | | logLevel | _Log level - 'debug', 'trace', 'info', 'warn', 'error', 'fatal', on any custom log level _ | string | no | | errorMessage | Error message to be logged in the file | string | no | | serviceName | Service name from which info was logged | string | yes | | methodName | Method name from which info was logged | string | yes | | errorObj | Error object that needs to be logged | object | yes | | callback | Callback method that is called after error logging (may return an error) | function | yes |

License

Apache 2.0