copy-on-write

A copy-on-write, union filesystem implementation for NodeJS

Modified/extended from the FS implementation in torrent-docker

WIP This module is still in-progress. There are many FUSE implementation details that still need to be added.

install

Installation might currently be a pain because this module depends on fuse-bindings and might not work by default on OSX. When it does work, install it with the standard:

npm install copy-on-write

usage

require('copy-on-write')('/path/to/mountpoint', {
  createFileStream: function (entry, offset) {
    // Return the byte stream for the given entry (a readable stat object)
  }
  createIndexStream: function (cb) {
    // Return a stream of stat objects in the filesystem
  }
}, function (err, filesytem) {
  // Do stuff with the filesystem
}

createFilesystem (mnt, opts, function (err, fs))

Creates a filesystem instance, mounted at mnt

opts:

1. createImageStream(entry, offset) - Create a readable stream for the entry.name file
2. createIndexStream()- Create a readable stream of stat objects for every file/dir in the FS
3. (optional) dir - directory to store indices/layers
4. (optional) db - LevelDB instance, default level(dir) by default
5. (optional) log - logger, noop by default

testing

Before running tests, make sure scripts/get-libfuse.sh is run (it will download/make the libfuse tests, which is a fairly extensive suite of FUSE tests).

npm run build:tests
npm test

makeTestFilesystem()

In test/util.js this function is provided to make it easier to mount and play with a test filesystem (that serves the content in test/test-fs). To use it:

makeTestFilesystem(<optional cow opts>, function (err, mountPoint, filesystem) {
  ...do stuff with filesystem
})

license

MIT