github.com/zostay/fssafe

This is a small go package that provides a tools for saving files atomically. It also provides tooling for testing loading and saving of files using the same interface.

Installation

There's nothing to install, but to add it to your project:

go get github.com/zostay/fssafe

Usage

Then to use it in your code:

package main

import (
	"fmt"
	"io"
	
	"github.com/zostay/fssafe"
)

func main() {
    loaderSaver := fssafe.NewFileSystemLoaderSaver("file.txt")

    // save a file, this will create a file named file.txt.new temporarily
    w, err := loaderSaver.Saver()
    if err != nil {
        panic(err)
    }

    fmt.Fprintln(w, "Hello, World!")
    w.Close()

    // If file.txt already exists, it will be renamed to file.txt.old.  The temporary
    // file.txt.new will be renamed to file.txt

    // load a file
    r, err := loaderSaver.Loader()
    if err != nil {
        panic(err)
    }

    data, err := io.ReadAll(r)
    if err != nil {
        panic(err)
    }

    fmt.Println(string(data))
    // Output: Hello, World!
}

Testing

Another loader/saver is provided that can be created using NewTestingLoaderSaver(). The saver just writes to a memory buffer and the loader reads from that memory buffer.

package main

import (
	"fmt"
	"io"
	
	"github.com/zostay/fssafe"
)

func main() {
    loaderSaver := fssafe.NewTestingLoaderSaver()

    // save to a memory buffer
    w, err := loaderSaver.Saver()
    if err != nil {
        panic(err)
    }

    fmt.Fprintln(w, "Hello, World!")
    w.Close()

    // load from the shared memory buffer
    r, err := loaderSaver.Loader()
    if err != nil {
        panic(err)
    }
    
    data, err := io.ReadAll(r)
    if err != nil {
        panic(err)
    }

    fmt.Println(string(data))
    // Output: Hello, World!
}

Copyright & License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.