Better resource management in Go using "Bracket pattern".

main.go

package main

import (
	"io/fs"
	"os"
)

// Manual
func bracket[R any](acquire func() (R, error), release func(R) error, use func(R) error) error {
	r, err := acquire()
	if err != nil {
		return err
	}

	if err = use(r); err != nil {
		if cerr := release(r); cerr != nil {
			return cerr
		}
		return err
	}

	return release(r)
}

// Semi auto
type Closer interface {
	Close() error
}

func withResource[R Closer](acquire func() (R, error), use func(R) error) error {
	return bracket(
		acquire,
		func(r R) error { return r.Close() },
		use,
	)
}

// Full auto
func withFile(filepath string, flag int, mode fs.FileMode, use func(*os.File) error) error {
	return withResource(func() (*os.File, error) { return os.OpenFile(filepath, flag, mode) }, use)
}

func main() {
	withFile("file.txt", os.O_CREATE, fs.ModeAppend, func(f *os.File) error {
		_, err := f.Write([]byte("hey!"))
		return err
	})
}