file-path-maker

file-path-maker is an npm module for organizing a steady flow of incoming files in a predictably growing tree of directories.

Description

Suppose an information system have to store about N files per day (hour, second etc.) in arbitrary directories under a common root. Once written, files are never modified, but their retention time is limited to T years (months etc.) after which all expired content must be deleted or compressed, moved to other media and so on.

The obvious solution for this is to have one directory per year, subdivided by month etc. Leaf directories correspond to the smallest time unit in use. They should contain the greatest number of files comfortable to work with at once. The exact choice depends on the flow rate, the retention time and the file system capabilities.

To implement such logic, file-path-maker provides the FilePathMaker class with the single API method called make that calculates paths like ${root}/${prefix}/${yyyy}/${mm}/${dd}/.../${file}.${ext} while creating necessary directories on the fly.

Installation

npm install file-path-maker

Usage

const {FilePathMaker} = require ('file-path-maker')

const fpm = new FilePathMaker ({
     root   :  '/var/filestore',
  // mode   :  0o777, 
  // format :  {year: 'numeric', month: '2-digit', day: '2-digit'},
})

const {
  rel,   //                `daily/${yyyy}/${mm}/${dd}/docs/file.ext`
  dir,   // `/var/filestore/daily/${yyyy}/${mm}/${dd}/docs`
  abs,   // `/var/filestore/daily/${yyyy}/${mm}/${dd}/docs/file.ext`
} = fpm.make ('docs/file.ext', 'daily')

Constructor Options

Name	Description
root	The absolute path of a directory containing all make results
mode	The newly created directories mode, see fs.mkdir
format	Intl.DateTimeFormat constructor options

The make method

parameters

Name	Description	Note
path	The path to append last	Mandatory
prefix	The string to place between the root and the date based part	Optional

result properties

Name	Description	Note
abs	The absolute generated path	path.sep as delimiter
rel	The generated path relative to root	'/' as delimiter
dir	The absolute directory name of the generated path	guaranteed to exist

Limitations

file-path-maker never checks for existing files nor path uniqueness. Subsequent make ('1.txt') calls may very well give identical results, so writing different content by those path will lead to data loss. It's up to the application to implement necessary checks, locking, using globally unique names and so on.

The make () method is synchronous and uses fs.mkdirSync internally. Potentially, this may lead to some performance issues.