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.