go-real-fs

A real filesystem that behaves normally and implements fs.FS and wraps os.DirFS.

Using fs.FS to represent filesystems has many advantages, but it can be clunky to work with for reasons outlined in this rejected proposal.

go-real-fs implements this behaviour like so:

package main

import (
    "github.com/sean9999/go-real-fs"
)

func main(){

    realFs := realfs.New()
    data, _ := realFs.ReadFile("/etc/passwd")
    fmt.Println("here is the contents of /etc/passwd")
    os.Stdout.Write(data)

}

go-real-fs simply rewrites paths from context-dependant to root-relative:

func (rfs realFS) correctPath(relativePath string) (string, error) {

	fullPath, err := filepath.Abs(relativePath)
	if err != nil {
		return "", err
	}
	return filepath.Rel("/", fullPath)

}

It's power comes from the fact that it satisfies interfaces from the fs package, allowing for modularity and testability. Let's say you wanted to create a storage-agnostic and testable key-value store:

type Database struct {
    filesystem realfs.WritableFs
}

func (d *Database) Get(name string) ([]byte, error) {
    return d.filesystem.OpenFile(name)
}

func (d *Databse) Set(name string, content []byte) error {
    return d.filesystem.WriteFile(name, content, 0640)
}

func (d *Database) Delete(name string) error {
    return d.filesystem.Remove(name)
}

To instantiate a real Databse you can do:

db := Database{realfs.NewWritable()} 

And to test is equally easy:

func TestDatabase(t *testing.T) {

    


}