Git object storage in Go (see http://git-scm.com/book/en/Git-Internals-Git-Objects#Object-Storage)

git-objects.go

package main

import (
	"bytes"
	"compress/zlib"
	"crypto/sha1"
	"fmt"
	"io/ioutil"
	"os"
	"path"
)

func logAndExit(err error) {
	fmt.Fprintln(os.Stderr, err)
	os.Exit(1)
}

func main() {
	content := "what is up, doc?"
	fmt.Println(content)

	header := fmt.Sprintf("blob %d\000", len(content))
	fmt.Printf("%q\n", header)

	store := header + content
	fmt.Printf("%q\n", store)

	h := sha1.New()
	fmt.Fprint(h, store)
	sha := fmt.Sprintf("%x", h.Sum(nil))
	fmt.Println(sha)

	var b bytes.Buffer
	w := zlib.NewWriter(&b)
	w.Write([]byte(store))
	w.Close()
	fmt.Printf("%q\n", b.Bytes())

	filepath := ".git/objects/" + sha[0:2] + "/" + sha[2:]

	err := os.MkdirAll(path.Dir(filepath), 0755)
	if err != nil {
		logAndExit(err)
	}

	err = ioutil.WriteFile(filepath, b.Bytes(), 0644)
	if err != nil {
		logAndExit(err)
	}
}