utils: move git functions to pkg/gitutils

Signed-off-by: Tibor Vass <tibor@docker.com>

gitutils/gitutils.go

@@ -0,0 +1,100 @@
+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"
+)
+
+// 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
+	}
+
+	fragment := u.Fragment
+	clone := cloneArgs(u, root)
+
+	if output, err := git(clone...); err != nil {
+		return "", fmt.Errorf("Error trying to use git: %s (%s)", err, output)
+	}
+
+	return checkoutGit(fragment, root)
+}
+
+func cloneArgs(remoteURL *url.URL, root string) []string {
+	args := []string{"clone", "--recursive"}
+	shallow := len(remoteURL.Fragment) == 0
+
+	if shallow && 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")
+	}
+
+	if remoteURL.Fragment != "" {
+		remoteURL.Fragment = ""
+	}
+
+	return append(args, remoteURL.String(), root)
+}
+
+func checkoutGit(fragment, root string) (string, error) {
+	refAndDir := strings.SplitN(fragment, ":", 2)
+
+	if len(refAndDir[0]) != 0 {
+		if output, err := gitWithinDir(root, "checkout", refAndDir[0]); err != nil {
+			return "", fmt.Errorf("Error trying to use git: %s (%s)", err, output)
+		}
+	}
+
+	if len(refAndDir) > 1 && len(refAndDir[1]) != 0 {
+		newCtx, err := symlink.FollowSymlinkInScope(filepath.Join(root, refAndDir[1]), root)
+		if err != nil {
+			return "", fmt.Errorf("Error setting git context, %q not within git root: %s", refAndDir[1], err)
+		}
+
+		fi, err := os.Stat(newCtx)
+		if err != nil {
+			return "", err
+		}
+		if !fi.IsDir() {
+			return "", fmt.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()
+}

gitutils/gitutils_test.go

@@ -0,0 +1,186 @@
+package gitutils
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+)
+
+func TestCloneArgsSmartHttp(t *testing.T) {
+	mux := http.NewServeMux()
+	server := httptest.NewServer(mux)
+	serverURL, _ := url.Parse(server.URL)
+
+	serverURL.Path = "/repo.git"
+	gitURL := serverURL.String()
+
+	mux.HandleFunc("/repo.git/info/refs", func(w http.ResponseWriter, r *http.Request) {
+		q := r.URL.Query().Get("service")
+		w.Header().Set("Content-Type", fmt.Sprintf("application/x-%s-advertisement", q))
+	})
+
+	args := cloneArgs(serverURL, "/tmp")
+	exp := []string{"clone", "--recursive", "--depth", "1", gitURL, "/tmp"}
+	if !reflect.DeepEqual(args, exp) {
+		t.Fatalf("Expected %v, got %v", exp, args)
+	}
+}
+
+func TestCloneArgsDumbHttp(t *testing.T) {
+	mux := http.NewServeMux()
+	server := httptest.NewServer(mux)
+	serverURL, _ := url.Parse(server.URL)
+
+	serverURL.Path = "/repo.git"
+	gitURL := serverURL.String()
+
+	mux.HandleFunc("/repo.git/info/refs", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/plain")
+	})
+
+	args := cloneArgs(serverURL, "/tmp")
+	exp := []string{"clone", "--recursive", gitURL, "/tmp"}
+	if !reflect.DeepEqual(args, exp) {
+		t.Fatalf("Expected %v, got %v", exp, args)
+	}
+}
+
+func TestCloneArgsGit(t *testing.T) {
+	u, _ := url.Parse("git://github.com/docker/docker")
+	args := cloneArgs(u, "/tmp")
+	exp := []string{"clone", "--recursive", "--depth", "1", "git://github.com/docker/docker", "/tmp"}
+	if !reflect.DeepEqual(args, exp) {
+		t.Fatalf("Expected %v, got %v", exp, args)
+	}
+}
+
+func TestCloneArgsStripFragment(t *testing.T) {
+	u, _ := url.Parse("git://github.com/docker/docker#test")
+	args := cloneArgs(u, "/tmp")
+	exp := []string{"clone", "--recursive", "git://github.com/docker/docker", "/tmp"}
+	if !reflect.DeepEqual(args, exp) {
+		t.Fatalf("Expected %v, got %v", exp, args)
+	}
+}
+
+func TestCheckoutGit(t *testing.T) {
+	root, err := ioutil.TempDir("", "docker-build-git-checkout")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(root)
+
+	gitDir := filepath.Join(root, "repo")
+	_, err = git("init", gitDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = gitWithinDir(gitDir, "config", "user.email", "test@docker.com"); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = gitWithinDir(gitDir, "config", "user.name", "Docker test"); err != nil {
+		t.Fatal(err)
+	}
+
+	if err = ioutil.WriteFile(filepath.Join(gitDir, "Dockerfile"), []byte("FROM scratch"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	subDir := filepath.Join(gitDir, "subdir")
+	if err = os.Mkdir(subDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	if err = ioutil.WriteFile(filepath.Join(subDir, "Dockerfile"), []byte("FROM scratch\nEXPOSE 5000"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	if err = os.Symlink("../subdir", filepath.Join(gitDir, "parentlink")); err != nil {
+		t.Fatal(err)
+	}
+
+	if err = os.Symlink("/subdir", filepath.Join(gitDir, "absolutelink")); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = gitWithinDir(gitDir, "add", "-A"); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = gitWithinDir(gitDir, "commit", "-am", "First commit"); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = gitWithinDir(gitDir, "checkout", "-b", "test"); err != nil {
+		t.Fatal(err)
+	}
+
+	if err = ioutil.WriteFile(filepath.Join(gitDir, "Dockerfile"), []byte("FROM scratch\nEXPOSE 3000"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	if err = ioutil.WriteFile(filepath.Join(subDir, "Dockerfile"), []byte("FROM busybox\nEXPOSE 5000"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = gitWithinDir(gitDir, "add", "-A"); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = gitWithinDir(gitDir, "commit", "-am", "Branch commit"); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err = gitWithinDir(gitDir, "checkout", "master"); err != nil {
+		t.Fatal(err)
+	}
+
+	cases := []struct {
+		frag string
+		exp  string
+		fail bool
+	}{
+		{"", "FROM scratch", false},
+		{"master", "FROM scratch", false},
+		{":subdir", "FROM scratch\nEXPOSE 5000", false},
+		{":nosubdir", "", true},   // missing directory error
+		{":Dockerfile", "", true}, // not a directory error
+		{"master:nosubdir", "", true},
+		{"master:subdir", "FROM scratch\nEXPOSE 5000", false},
+		{"master:parentlink", "FROM scratch\nEXPOSE 5000", false},
+		{"master:absolutelink", "FROM scratch\nEXPOSE 5000", false},
+		{"master:../subdir", "", true},
+		{"test", "FROM scratch\nEXPOSE 3000", false},
+		{"test:", "FROM scratch\nEXPOSE 3000", false},
+		{"test:subdir", "FROM busybox\nEXPOSE 5000", false},
+	}
+
+	for _, c := range cases {
+		r, err := checkoutGit(c.frag, gitDir)
+
+		fail := err != nil
+		if fail != c.fail {
+			t.Fatalf("Expected %v failure, error was %v\n", c.fail, err)
+		}
+		if c.fail {
+			continue
+		}
+
+		b, err := ioutil.ReadFile(filepath.Join(r, "Dockerfile"))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if string(b) != c.exp {
+			t.Fatalf("Expected %v, was %v\n", c.exp, string(b))
+		}
+	}
+}