Awesome

vfs for golang

vfs is library to support virtual filesystems. It provides basic abstractions of filesystems and implementations, like OS accessing the file system of the underlying OS and memfs a full filesystem in-memory.

Usage

$ go get github.com/blang/vfs

Note: Always vendor your dependencies or fix on a specific version tag.

import github.com/blang/vfs

// Create a vfs accessing the filesystem of the underlying OS
var osfs vfs.Filesystem = vfs.OS()
osfs.Mkdir("/tmp", 0777)

// Make the filesystem read-only:
osfs = vfs.ReadOnly(osfs) // Simply wrap filesystems to change its behaviour

// os.O_CREATE will fail and return vfs.ErrReadOnly
// os.O_RDWR is supported but Write(..) on the file is disabled
f, _ := osfs.OpenFile("/tmp/example.txt", os.O_RDWR, 0)

// Return vfs.ErrReadOnly
_, err := f.Write([]byte("Write on readonly fs?"))
if err != nil {
    fmt.Errorf("Filesystem is read only!\n")
}

// Create a fully writable filesystem in memory
mfs := memfs.Create()
mfs.Mkdir("/root", 0777)

// Create a vfs supporting mounts
// The root fs is accessing the filesystem of the underlying OS
fs := mountfs.Create(osfs)

// Mount a memfs inside /memfs
// /memfs may not exist
fs.Mount(mfs, "/memfs")

// This will create /testdir inside the memfs
fs.Mkdir("/memfs/testdir", 0777)

// This would create /tmp/testdir inside your OS fs
// But the rootfs `osfs` is read-only
fs.Mkdir("/tmp/testdir", 0777)

Check detailed examples below. Also check the GoDocs.

Why should I use this lib?

• Only Stdlib
• (Nearly) Fully tested (Coverage >90%)
• Easy to create your own filesystem
• Mock a full filesystem for testing (or use included memfs)
• Compose/Wrap Filesystems ReadOnly(OS()) and write simple Wrappers
• Many features, see GoDocs and examples below

Features and Examples

• OS Filesystem support
• ReadOnly Wrapper
• DummyFS for quick mocking
• MemFS - full in-memory filesystem
• MountFS - support mounts across filesystems

Current state: ALPHA

While the functionality is quite stable and heavily tested, interfaces are subject to change.

You need more/less abstraction? Let me know by creating a Issue, thank you.

Motivation

I simply couldn't find any lib supporting this wide range of variation and adaptability.

Contribution

Feel free to make a pull request. For bigger changes create a issue first to discuss about it.

License

See LICENSE file.