Introduction

This lib produces what I would call a separate, one off, log files for some specific error or purpose. The idea is to output 'more' information to this file and prevent the normal log from becoming too noisy.

To prevent this new 'tangent' logging from becoming too noisy this lib debounces the number of writes it attempts during a period of time. There are a number of configuration properties, so take a look at the usage.

Installation

%> npm install tangent-file --save

Usage

A simple and typical usage is below. This uses the default values to setup the TangentFile and then calls .write(String) to push data into a file.

config = {}

t = new TangentFile(config)

/**
 *  This check and bit of code then might get hit often as a process or web
 *  server is running.  The tangent file will bounce the request to write
 *  and only write once during a given period.
 */
if err?
  t.write(...some json..., (err, isWritten) -> )

Configuration

The defaults:

defaults =
  outDirectory      : '~/tmp'
  startingNumber    : 1
  name              : 'tangent'
  number            : null
  maxFiles          : 10
  debounceDelay     : 1000      # 1 second
  filenameTemplate  : "{name}-{number}.log"

The TangentFile constructor can accept a configuration object and will recognize the following properties:

outDirectory

The directory where new tangent files will be written for this instance

startingNumber

The default template for the tangent file is something like '{name}-{number}.log' and startingNumber will be the value used as the first 'number'

name

This value will be interpolated into the file name. The default filename template is '{name}-{number}.log' and so given a name of 'activity-errors' and a number of 12 would produce a new long name 'activity-errors-12.log'.

number

This value will be interpolated into the file name. The default filename template is '{name}-{number}.log' and so given a name of 'tangent' and a number of 12 would produce a new long name 'tangent-12.log'.

maxFiles

When the number of logs exceeds this number the value interpolated into the log file name will roll and start again at the value held by startingNumber.

debounceDelay

A file is writen only if it's outside this delay. So given a delay of 10seconds then ten seconds after the last write will another write actually occur.

filenameTemplate

This value is a string which will be used to create new file names. It it uses a mini templating system that will substitute the keys surrounding by '{' and '}' with the values for those keys. Right now the map/object that is used is the consists only of the 'name' provided during instantiation and a number that increments internally. (May include more in the future).

License

See license file.

The use and distribution terms for this software are covered by the Eclipse Public License 1.0, which can be found in the file 'license' at the root of this distribution. By using this software in any fashion, you are agreeing to be bound by the terms of this license. You must not remove this notice, or any other, from this software.