tracer for node.js

A powerful and customizable logging library for node.js.

===========

Features

---

• print log messages with timestamp, file name, method name, line number, path or call stack
• be customized output format with micro-template and timestamp format
• support user-defined logging levels
• add easily any transport
• support filter functions, so print statements in full color and font (color console)

Install

---

npm install tracer --save

Usage

Add to your code:

Simple Console

var logger = require('tracer').console()

Color Console

var logger = require('tracer').colorConsole()

Set Output Level

var logger = require('tracer').colorConsole({ level: 'warn' })

Simple Example

Simple Console

var logger = require('tracer').console();

logger.log('hello');
logger.trace('hello', 'world');
logger.debug('hello %s',  'world', 123);
logger.info('hello %s %d',  'world', 123, {foo:'bar'});
logger.warn('hello %s %d %j', 'world', 123, {foo:'bar'});
logger.error('hello %s %d %j', 'world', 123, {foo:'bar'}, [1, 2, 3, 4], Object);

$ node example/console.js
2012-03-02T13:35:22.83Z <log> console.js:3 (Object.<anonymous>) hello
2012-03-02T13:35:22.85Z <trace> console.js:4 (Object.<anonymous>) hello world
2012-03-02T13:35:22.85Z <debug> console.js:5 (Object.<anonymous>) hello world 123
2012-03-02T13:35:22.85Z <info> console.js:6 (Object.<anonymous>) hello world 123 { foo: 'bar' }
2012-03-02T13:35:22.85Z <warn> console.js:7 (Object.<anonymous>) hello world 123 {"foo":"bar"}
2012-03-02T13:35:22.85Z <error> console.js:8 (Object.<anonymous>) hello world 123 {"foo":"bar"} [ 1, 2, 3, 4 ] function Object() { [native code] }

Color Console

var logger = require('tracer').colorConsole()

logger.log('hello')
logger.trace('hello', 'world')
logger.debug('hello %s', 'world', 123)
logger.info('hello %s %d', 'world', 123, { foo: 'bar' })
logger.warn('hello %s %d %j', 'world', 123, { foo: 'bar' })
logger.error(
  'hello %s %d %j',
  'world',
  123,
  { foo: 'bar' },
  [1, 2, 3, 4],
  Object
)

Daily Log

var logger = require('tracer').dailyfile({
  root: '.',
  maxLogFiles: 10,
  allLogsFileName: 'myAppName'
})

logger.log('hello')
logger.trace('hello', 'world')
logger.debug('hello %s', 'world', 123)
logger.info('hello %s %d', 'world', 123, { foo: 'bar' })
logger.warn('hello %s %d %j', 'world', 123, { foo: 'bar' })
logger.error(
  'hello %s %d %j',
  'world',
  123,
  { foo: 'bar' },
  [1, 2, 3, 4],
  Object
)

dailylog will output all types log to diff files every day like log4j and if we provide allLogsFileName then all logs will be move to that file too.

Advanced Example

some helper package is need, so install -dev for running examples

npm install -dev tracer

Take a look at the examples directory for different examples.

Set logging level

the level option support index (number) or method name.

var logger = require('tracer').console({ level: 'warn' })

equal

var logger = require('tracer').console({ level: 4 })

var logger = require('tracer').console({ level: 'warn' })
logger.log('hello')
logger.trace('hello', 'world')
logger.debug('hello %s', 'world', 123)
logger.info('hello %s %d', 'world', 123, { foo: 'bar' })
logger.warn('hello %s %d %j', 'world', 123, { foo: 'bar' })
logger.error(
  'hello %s %d %j',
  'world',
  123,
  { foo: 'bar' },
  [1, 2, 3, 4],
  Object
)

//$ node example/level.js
//2012-03-02T13:41:33.29Z <warn> level.js:6 (Object.<anonymous>) hello world 123 {"foo":"bar"}
//2012-03-02T13:41:33.30Z <error> level.js:7 (Object.<anonymous>) hello world 123 {"foo":"bar"} [ 1, 2, 3, 4 ] function Object() { [native code] }

//log,trace, debug and info level was not ouputed

Customize output format

format tag:

• timestamp: current time
• title: method name, default is 'log', 'trace', 'debug', 'info', 'warn', 'error','fatal'
• level: method level, default is 'log':0, 'trace':1, 'debug':2, 'info':3, 'warn':4, 'error':5, 'fatal':6
• message: printf message, support %s string, %d number, %j JSON and auto inspect
• file: file name
• line: line number
• pos: position
• path: file's path
• folder: file's parent folder
• method: method name of caller
• stack: call stack message

we use tinytim micro-template system to output log. see details tinytim. and, we use Date Format to format datetime.

var logger = require('tracer').console({
  format: '{{timestamp}} <{{title}}> {{message}} (in {{file}}:{{line}})',
  dateformat: 'HH:MM:ss.L'
})

Or, you can set special format for output method

var logger = require('tracer').colorConsole({
  format: [
    '{{timestamp}} <{{title}}> {{message}} (in {{file}}:{{line}})', //default format
    {
      error:
        '{{timestamp}} <{{title}}> {{message}} (in {{file}}:{{line}})\nCall Stack:\n{{stack}}' // error format
    }
  ],
  dateformat: 'HH:MM:ss.L',
  preprocess: function(data) {
    data.title = data.title.toUpperCase()
  }
})

the preprocess method is a choice for changing tag.

Customize output methods

var colors = require('colors')

var logger = require('tracer').colorConsole({
  level: 'log1',
  methods: ['log0', 'log1', 'log2', 'log3', 'log4', 'log5'],
  filters: [colors.underline, colors.yellow]
})
logger.log0('hello')
logger.log1('hello', 'world')
logger.log2('hello %s', 'world', 123)
logger.log4('hello %s %d', 'world', 123)
logger.log5('hello %s %d', 'world', 123)

Customize filters

each filtes function was called. the function is synchronous and must be like

function f1(str) {
  return str.toUpperCase()
}

About Colors.js

var colors = require('colors')
var logger = require('tracer').colorConsole({
  filters: [
    f1,
    colors.underline,
    colors.blue, //default filter
    //the last item can be custom filter. here is "warn" and "error" filter
    {
      warn: colors.yellow,
      error: [f1, colors.red, colors.bold]
    }
  ]
})

the filter support key-function pair, example: color_console.js

{
		filters : {
			//log : colors.black,
			trace : colors.magenta,
			debug : colors.blue,
			info : colors.green,
			warn : colors.yellow,
			error : [ colors.red, colors.bold ]
		}
}

and the filters is an array, the last item can be custom filter. see example:filter.js

Log File Transport

var fs = require('fs')

var logger = require('tracer').console({
  transport: function(data) {
    console.log(data.output)
    fs.appendFile('./file.log', data.rawoutput + '\n', err => {
      if (err) throw err
    })
  }
})

logger.log('hello')
logger.trace('hello', 'world')
logger.debug('hello %s', 'world', 123)
logger.info('hello %s %d', 'world', 123, { foo: 'bar' })
logger.warn('hello %s %d %j', 'world', 123, { foo: 'bar' })
logger.error(
  'hello %s %d %j',
  'world',
  123,
  { foo: 'bar' },
  [1, 2, 3, 4],
  Object
)

Stream Transport

var fs = require('fs')

var logger = require('tracer').console({
  transport: function(data) {
    console.log(data.output)
    var stream = fs
      .createWriteStream('./stream.log', {
        flags: 'a',
        encoding: 'utf8',
        mode: 0666
      })
      .write(data.rawoutput + '\n')
  }
})

logger.log('hello')
logger.trace('hello', 'world')
logger.debug('hello %s', 'world', 123)
logger.info('hello %s %d', 'world', 123, { foo: 'bar' })
logger.warn('hello %s %d %j', 'world', 123, { foo: 'bar' })
logger.error(
  'hello %s %d %j',
  'world',
  123,
  { foo: 'bar' },
  [1, 2, 3, 4],
  Object
)

MongoDB Transport

var mongo = require('mongoskin')
var db = mongo.db('127.0.0.1:27017/test?auto_reconnect')

var log_conf = {
  transport: function(data) {
    console.log(data.output)
    var loginfo = db.collection('loginfo')
    loginfo.insert(data, function(err, log) {
      if (err) {
        console.error(err)
      }
    })
  }
}

var logger = require('tracer').console(log_conf)

logger.log('hello')
logger.trace('hello', 'world')
logger.debug('hello %s', 'world', 123)
logger.info('hello %s %d', 'world', 123, { foo: 'bar' })
logger.warn('hello %s %d %j', 'world', 123, { foo: 'bar' })
logger.error(
  'hello %s %d %j',
  'world',
  123,
  { foo: 'bar' },
  [1, 2, 3, 4],
  Object
)

console.log('\n\n\npress ctrl-c to exit')

Defining Multiple Transport

var fs = require('fs');
var logger = require('tracer').console({
	transport: [
		function (data) {
			fs.appendFile('./file.log', data.rawoutput + '\n', (err) => {
				if (err) throw err;
			});
		},
		function(data) {
			console.log(data.output);
		}
	]
});
logger.log('hello');
logger.trace('hello', 'world');
logger.debug('hello %s', 'world', 123);
logger.info('hello %s %d', 'world', 123, {foo: 'bar'});
logger.warn('hello %s %d %j', 'world', 123, {foo: 'bar'});
logger.error('hello %s %d %j', 'world', 123, {foo: 'bar'}, [1, 2, 3, 4], Object);

Define your logging helper

the work is like color_console.js

var colors = require('colors')
module.exports = function(conf) {
  return require('./console')(
    {
      filters: {
        //log : colors.black,
        trace: colors.magenta,
        debug: colors.blue,
        info: colors.green,
        warn: colors.yellow,
        error: [colors.red, colors.bold]
      }
    },
    conf
  )
}

Customize output Object's properties