github.com/liamg/memoryfs

memoryfs

An in-memory filesystem implementation of io/fs.FS.

memoryfs implements all of the currently defined io/fs interfaces:

• fs.FS
• fs.GlobFS
• fs.ReadDirFS
• fs.ReadFileFS
• fs.StatFS
• fs.SubFS

It also allows the creation of files and directories.

Example

package main

import (
    "fmt"
    "io/fs"

    "github.com/liamg/memoryfs"
)

func main() {

    memfs := memoryfs.New()

    if err := memfs.MkdirAll("my/dir", 0o700); err != nil {
        panic(err)
    }

    if err := memfs.WriteFile("my/dir/file.txt", []byte("hello world"), 0o600); err != nil {
        panic(err)
    }

    data, err := fs.ReadFile(memfs, "my/dir/file.txt")
    if err != nil {
        panic(err)
    }

    fmt.Println(string(data))
}

Lazy Loading

If you are mirroring a disk file-system in memory, it can become very inefficient when large files are in use. For this scenario, the WriteLazyFile method is recommended. It allows you to add a file whose content will be provided on-demand by calling the LazyOpener function.