Node js Logging

Question

Is there any library which will help me to handle logging in my Node Js application  All I want to do is  I want to write all logs into a File and also I need an options like rolling out the file after certain size or date      I have incorporated log4js im trying to keep all the configuration details in one file and use only the methods in other application files for ease of maintenance   But it doesnt work as expected  Here is what I m trying to do  var log4js   require  log4js     log4js clearAppenders   log4js loadAppender  file    log4js addAppender log4js appenders file  test log     test    var logger   log4js getLogger  test    logger setLevel  ERROR      var traceLogger   function  message            logger trace  message            var errorLogger   function  message            logger trace message            exports trace   traceLogger  exports error   errorLogger    I have included this file in other files and tried  log error   Hello Error Message      But it is not working  Is there anything wrong in this

User · Answer

You can also use npmlog by issacs  recommended in  https   npmjs org doc coding-style html   You can find this module here  https   github com isaacs npmlog

User · Answer

A  nodejslogger  module can be used for simple logging  It has three levels of logging  INFO  ERROR  DEBUG   var logger   require  nodejslogger   logger init   file   output-file    mode   DIE      D   Debug  I   Info  E   Error  logger debug  Debug logs   logger info  Info logs   logger error  Error logs     The module can be accessed at   https   www npmjs com package nodejslogger

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Winston is strong choice for most of the developers  I have been using winston for long  Recently I used winston with with papertrail which takes the application logging to next level  Here is a nice screenshot from their site   How its useful  you can manage logs from different systems at one place  this can be very useful when you have two backend communicating and can see logs from both at on place   Logs are live  you can see realtime logs of your production server   Powerful search and filter  you can create alerts to send you email if it encounters specific text in log    and you can find more http   help papertrailapp com kb how-it-works event-viewer  A simple configuration using winston winston-express and winston-papertrail node modules  import winston from  winston   import expressWinston from  express-winston         Requiring  winston-papertrail  will expose     winston transports Papertrail     require  winston-papertrail   Papertrail     create winston transport for Papertrail var winstonPapertrail   new winston transports Papertrail     host   logsX papertrailapp com     port  XXXXX     app use expressWinston logger     transports   winstonPapertrail     meta  true     optional  control whether you want to log the meta data about the request  default to true    msg   quot HTTP   req method     req url   quot      optional  customize the default logging message  E g   quot   res statusCode     req method     res responseTime  ms   req url   quot    expressFormat  true     Use the default Express morgan request formatting  Enabling this will override any msg if true  Will only output colors with colorize set to true   colorize  true     Color the text and status code  using the Express morgan color palette  text  gray  status  default green  3XX cyan  4XX yellow  5XX red     ignoreRoute  function  req  res    return false       optional  allows to skip some log messages based on request and or response

User · Answer

Winston is a pretty good logging library  You can write logs out to a file using it   Code would look something like   var winston   require  winston     var logger   new  winston Logger      transports        new  winston transports Console    json  false  timestamp  true         new winston transports File   filename    dirname     debug log   json  false           exceptionHandlers        new  winston transports Console    json  false  timestamp  true         new winston transports File   filename    dirname     exceptions log   json  false           exitOnError  false      module exports   logger    You can then use this like   var logger   require    log     logger info  log to file

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The  logger setLevel  ERROR     is causing the problem  I do not understand why  but when I set it to anything other than  ALL   nothing gets printed in the file  I poked around a little bit and modified your code  It is working fine for me  I created two files   logger js  var log4js   require  log4js    log4js clearAppenders   log4js loadAppender  file    log4js addAppender log4js appenders file  test log     test    var logger   log4js getLogger  test    logger setLevel  ERROR     var getLogger   function        return logger      exports logger   getLogger      logger test js  var logger   require    logger js    var log   logger logger   log error  ERROR message    log trace  TRACE message      When I run  node logger test js   I see only  ERROR message  in test log file  If I change the level to  TRACE  then both lines are printed on test log

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Scribe JS Lightweight Logger  I have looked through many loggers  and I wasn t able to find a lightweight solution - so I decided to make a simple solution that is posted on github    Saves the file which are organized by user  date  and level Gives you a pretty output  we all love that  Easy-to-use HTML interface   I hope this helps you out   Online Demo  http   bluejamesbond github io Scribe js   Secure Web Access to Logs    Prints Pretty Text to Console Too     Web Access    Github  https   github com bluejamesbond Scribe js

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Observe that errorLogger is a wrapper around logger trace  But the level of logger is ERROR so logger trace will not log its message to logger s appenders   The fix is to change logger trace to logger error in the body of errorLogger

User · Answer

Each answer is 5 6 years old  so bit outdated or depreciated  Let s talk in 2020  simple-node-logger is simple multi-level logger for console  file  and rolling file appenders  Features include   levels  trace  debug  info  warn  error and fatal levels  plus all and off   flexible appender formatters with default to HH mm ss SSS LEVEL message add appenders to send output to console  file  rolling file  etc  change log levels on the fly  domain and category columns  overridable format methods in base appender  stats that track counts of all log statements including warn  error  etc   You can easily use it in any nodejs web application        create a stdout console logger   const log   require  simple-node-logger   createSimpleLogger     or      create a stdout and file logger   const log   require  simple-node-logger   createSimpleLogger  project log     or      create a custom timestamp format for log statements   const SimpleNodeLogger   require  simple-node-logger      opts           logFilePath  mylogfile log         timestampFormat  YYYY-MM-DD HH mm ss SSS          log   SimpleNodeLogger createSimpleLogger  opts     or      create a file only file logger   const log   require  simple-node-logger   createSimpleFileLogger  project log     or      create a rolling file logger based on date time that fires process events   const opts           errorEventName  error          logDirectory   mylogfiles      NOTE  folder must exist and be writable            fileNamePattern  roll- lt DATE gt  log            dateFormat  YYYY MM DD         const log   require  simple-node-logger   createRollingFileLogger  opts     Messages can be logged by   log info  this is logged info message     log warn  this is logged warn message    etc    PLUS POINT  It can send logs to console or socket  You can also append to log levels  This is the most effective and easy way to handle logs functionality

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Log4js is one of the most popular logging library for nodejs application   It supports many cool features    Coloured console logging Replacement of node s console log functions  optional  File appender  with log rolling based on file size SMTP  GELF  hook io  Loggly appender Multiprocess appender  useful when you ve got worker processes  A logger for connect express servers Configurable log message layout patterns Different log levels for different log categories  make some parts  of your app log as DEBUG  others only ERRORS  etc     Example    Installation  npm install log4js Configuration    config log4js json      appenders                    type    console            layout                  type    pattern                pattern     m                      category    app                   category    test-file-appender            type    file            filename    log file log            maxLogSize   10240           backups   3           layout                  type    pattern                pattern     d dd MM hh mm   -5p  m                      replaceConsole   true    Usage     var log4js   require   log4js     log4js configure     config log4js json     var logger   log4js getLogger   test-file-appender        log4js getLogger  app   will return logger that prints log to the console logger debug  Hello log4js      store log in file

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