Log Errors

logs errors based on environment
- development gets full color-coded errors
- production error logs use syslog error headings so they will be picked up by logwatch et al
- production only logs serious errors (level 3 and below) to reduce noise
request attrs logged if passed request object
response returned if passed response object

Quickstart

var	logErrors 	= require('log-errors'),
	logProd 	= logErrors.production,
	logDev 		= logErrors.development;

try {
	throw new error("funky");
} catch (e) {
	logDev(e);
}

This will output in colored text:

Error name: Error

Error object:

{  	Error: 		funky,
   	message: 	'funky',
   	type: 		undefined,
   	stack:  	Getter/Setter,
   	arguments: 	undefined }

Stack trace:

'Error: funky
    at Object.<anonymous> (/home/andy/lib/modules/npm/log-errors/lib/development.js:16:12)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)'

Using in Express.js

It will also log request url + query info.

var	logErrors 	= require('log-errors'),
	logProd 	= logErrors.production,
	logDev 		= logErrors.development;


// add this at very bottom (below all route handlers)
// it is designed to catch the errors passed by next(err) calls

app.configure('production', function() {
	app.use(logProd);
});

app.configure('development', function() {
	app.use(logDev);
	// equates to:
	// app.use(function(err, req, res, next) {
		// logDev(err, req, res, next);
	// });
});

Example Output:

Error name: Error

Request:

url: someurl
query: ?some=random&query=params

Error object:

{  	Error: 		funky,
   	message: 	'funky',
   	type: 		undefined,
   	stack:  	Getter/Setter,
   	arguments: 	undefined }

Stack trace:

'Error: funky
    at Object.<anonymous> (/home/andy/lib/modules/npm/log-errors/lib/development.js:16:12)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)'

Docs

Info printed to STDOUT

error name: (err.name)
error message (err.message)
error logLevel (err.logLevel)
error responseCode (err.resCode)
request url (req.url)
request query (req.query)

HTTP Response

If passed a response object then the logger will return this with the response code specified in the error (err.resCode). It defaults to sending a 500 server error with the body {error: 'Error'}.

var logErrors   = require('log-errors'),
    logDev      = logErrors.development;

  // will call res.send(403, {"error":"random"})
  logDev({resCode:403, name:"random"}, req, res);

Log Levels

Must be one of the 8 unix log levels used in the Visionmedia Logging Module.
Defaults to 'info' level if not passed one of the 8 listed.

Base Log Class

Production and development loggers inherit from this.
If app is an eventEmitter then the 'seriousError' evt will be prodcast when using the productionLogger.

var LogClass = function (env, app) {
    this.env = env;
    this.app = app;
};

Development Logger

Always prints full error in colored text.

var logDev 	= require('log-errors').development;
logDev(new Error('development error msg'));

Production Logger

Will only print error info if error.LogLevel is 3 or below, ie ['error', 'critical', 'alert', 'emergency']

var logProd = require('log-errors').production,
    err     = newError('some message about the error');

err.logLevel = 'critical'
logProd(err);

'seriousError' Evt

If error.LogLevel is 3 or below and this.app is an eventEmitter then the 'seriousError' evt will be prodcast when using the productionLogger.
It will NOT be broadcast if the error.doNotKill is truthy

    if (!err.doNotKill) {
      appErrorHandler && this.app.emit('seriousError');
    }

Using in Conjunction with Custom Errors npm Module

If your errors inherit from the custom errors class then the extra error attrs (logLevel, name, message etc) are already added.
However, the logger should work fine with the built in base error class too.

var valErr 		= require('custom-errors').general.ValidationError,
	logErrors 	= require('log-errors'),
	logProd 	= logErrors.production,
	logDev 		= logErrors.development;

try {
	throw new valErr("funky");
} catch (e) {
	logDev(e);
}

Outputs:

Error name: Validation

Error object:

{ logLevel: 'warn',
  message: 'funky',
  name: 'Validation',
  resCode: 400,
  [stack]: [Getter/Setter] }

Stack trace:

'Validation: funky
    at Object.<anonymous> (/home/andy/lib/modules/npm/log-errors/lib/development.js:18:12)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)'

techjacker/log-errors