gitfs

this example is nice because it has a different committer vs author timestamp https://github.com/tianon/docker-bash/commit/eb7e541caccc813d297e77cf4068f89553256673 https://github.com/docker-library/official-images/blob/8718b8afb62ff1a001d99bb4f77d95fe352ba187/library/bash

repo, err := git.Clone(memory.NewStorage(), nil, &git.CloneOptions{
	URL:          "https://github.com/tianon/docker-bash.git",
	SingleBranch: true,
})
if err != nil {
	panic(err)
}

commit, err := gitfs.CommitHash(repo, "eb7e541caccc813d297e77cf4068f89553256673")
if err != nil {
	panic(err)
}

f, err := fs.Sub(commit, "5.2")
if err != nil {
	panic(err)
}

h := sha256.New()

if err := tarscrub.WriteTar(f, h); err != nil {
	panic(err)
}

fmt.Printf("%x\n", h.Sum(nil))

Output:
011c8eda9906b94916a14e7969cfcff3974f1fbf2ff7b8e5c1867ff491dc01d3

this example is nice because it has some intentionally dangling symlinks in it that trip things up if they aren't implemented correctly! (see also pkg/tarscrub/git_test.go)

repo, err := git.Clone(memory.NewStorage(), nil, &git.CloneOptions{
	URL:          "https://github.com/varnish/docker-varnish.git",
	SingleBranch: true,
})
if err != nil {
	panic(err)
}

commit, err := gitfs.CommitHash(repo, "0c295b528f28a98650fb2580eab6d34b30b165c4")
if err != nil {
	panic(err)
}

f, err := fs.Sub(commit, "stable/debian")
if err != nil {
	panic(err)
}

h := sha256.New()

if err := tarscrub.WriteTar(f, h); err != nil {
	panic(err)
}

fmt.Printf("%x\n", h.Sum(nil))

Output:
3aef5ac859b23d65dfe5e9f2a47750e9a32852222829cfba762a870c1473fad6