moby/pkg/gitutils/gitutils.go
Tonis Tiigi 493a6c3d41 Allow checking out any ref in gitutils
Also changes so that shallow fetch is performed
even when a specific ref is specified.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
2017-05-04 14:14:50 -07:00

122 lines
3.2 KiB
Go

package gitutils
import (
"fmt"
"io/ioutil"
"net/http"
"net/url"
"os"
"os/exec"
"path/filepath"
"strings"
"github.com/docker/docker/pkg/symlink"
"github.com/docker/docker/pkg/urlutil"
"github.com/pkg/errors"
)
// Clone clones a repository into a newly created directory which
// will be under "docker-build-git"
func Clone(remoteURL string) (string, error) {
if !urlutil.IsGitTransport(remoteURL) {
remoteURL = "https://" + remoteURL
}
root, err := ioutil.TempDir("", "docker-build-git")
if err != nil {
return "", err
}
u, err := url.Parse(remoteURL)
if err != nil {
return "", err
}
if out, err := gitWithinDir(root, "init"); err != nil {
return "", errors.Wrapf(err, "failed to init repo at %s: %s", root, out)
}
ref, subdir := getRefAndSubdir(u.Fragment)
fetch := fetchArgs(u, ref)
u.Fragment = ""
// Add origin remote for compatibility with previous implementation that
// used "git clone" and also to make sure local refs are created for branches
if out, err := gitWithinDir(root, "remote", "add", "origin", u.String()); err != nil {
return "", errors.Wrapf(err, "failed add origin repo at %s: %s", u.String(), out)
}
if output, err := gitWithinDir(root, fetch...); err != nil {
return "", errors.Wrapf(err, "error fetching: %s", output)
}
return checkoutGit(root, ref, subdir)
}
func getRefAndSubdir(fragment string) (ref string, subdir string) {
refAndDir := strings.SplitN(fragment, ":", 2)
ref = "master"
if len(refAndDir[0]) != 0 {
ref = refAndDir[0]
}
if len(refAndDir) > 1 && len(refAndDir[1]) != 0 {
subdir = refAndDir[1]
}
return
}
func fetchArgs(remoteURL *url.URL, ref string) []string {
args := []string{"fetch", "--recurse-submodules=yes"}
shallow := true
if strings.HasPrefix(remoteURL.Scheme, "http") {
res, err := http.Head(fmt.Sprintf("%s/info/refs?service=git-upload-pack", remoteURL))
if err != nil || res.Header.Get("Content-Type") != "application/x-git-upload-pack-advertisement" {
shallow = false
}
}
if shallow {
args = append(args, "--depth", "1")
}
return append(args, "origin", ref)
}
func checkoutGit(root, ref, subdir string) (string, error) {
// Try checking out by ref name first. This will work on branches and sets
// .git/HEAD to the current branch name
if output, err := gitWithinDir(root, "checkout", ref); err != nil {
// If checking out by branch name fails check out the last fetched ref
if _, err2 := gitWithinDir(root, "checkout", "FETCH_HEAD"); err2 != nil {
return "", errors.Wrapf(err, "error checking out %s: %s", ref, output)
}
}
if subdir != "" {
newCtx, err := symlink.FollowSymlinkInScope(filepath.Join(root, subdir), root)
if err != nil {
return "", errors.Wrapf(err, "error setting git context, %q not within git root", subdir)
}
fi, err := os.Stat(newCtx)
if err != nil {
return "", err
}
if !fi.IsDir() {
return "", errors.Errorf("error setting git context, not a directory: %s", newCtx)
}
root = newCtx
}
return root, nil
}
func gitWithinDir(dir string, args ...string) ([]byte, error) {
a := []string{"--work-tree", dir, "--git-dir", filepath.Join(dir, ".git")}
return git(append(a, args...)...)
}
func git(args ...string) ([]byte, error) {
return exec.Command("git", args...).CombinedOutput()
}